A Monograph of the Baltic Amber Bees and Evolution of the Apoidea (Hymenoptera)

A MONOGRAPH OF THE BALTIC AMBER BEES AND EVOLUTION OF THE APOIDEA (HYMENOPTERA)

MICHAEL S. ENGEL Research Scientist, Division of Invertebrate Zoology, Presently: Research Associate, Division of Invertebrate Zoology, American Museum of Natural History; Fellow, the Linnean Society of London; Assistant Curator, Division of Entomology, Natural History Museum and Biodiversity Research Center; Assistant Professor, Department of Ecology and Evolutionary Biology, 1460 Jayhawk Boulevard, Snow Hall, University of Kansas, Lawrence, Kansas 66045-7523

BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY Number 259, 192 pp., 123 ®gures, 7 color plates, 15 tables Issued April 16, 2001 Price: $17.00 a copy

Copyright ᭧ American Museum of Natural History 2001 ISSN 0003-0090 Photomicrograph of the holotype (IMGP-K72) of Glyptapis mirabilis Cockerell. CONTENTS Abstract ...... 5 Zusammenfassung ...... 6 Introduction ...... 7 Historical Review ...... 13 Age and Origin of Amber ...... 15 Materials and Methods ...... 17 Specimen Preparation and Study ...... 18 Format ...... 18 General Morphology ...... 19 Prosoma ...... 20 Mesosoma ...... 23 Metasoma ...... 32 Systematic Paleontology ...... 33 Superfamily Apoidea Latreille ...... 34 Division Apiformes ...... 35 Short-Tongued Versus Long-Tongued Bees ...... 35 Short-Tongued Bees ...... 36 Family Halictidae Thomson ...... 36 Subfamily Halictinae Thomson ...... 36 Tribe Halictini Thomson ...... 37 Genus Electrolictus, new genus ...... 38 Family Paleomelittidae, new family ...... 41 Genus Paleomelitta, new genus ...... 42 Family Melittidae Schenck ...... 44 Subfamily Macropidinae Robertson ...... 46 Tribe Eomacropidini, new tribe ...... 46 Genus Eomacropis, new genus ...... 46 Long-Tongued Bees ...... 49 Family Megachilidae Latreille ...... 49 Subfamily Lithurginae Newman ...... 50 Tribe Protolithurgini, new tribe ...... 51 Genus Protolithurgus, new genus ...... 51 Subfamily Megachilinae Latreille ...... 53 Tribe Osmiini Newman ...... 54 Genus Glyptapis Cockerell ...... 56 Genus Ctenoplectrella Cockerell ...... 68 Genus Glaesosmia, new genus ...... 75 Family Apidae Latreille ...... 76 Subfamily Xylocopinae Latreille ...... 77 Tribe Boreallodapini, new tribe ...... 77 Genus Boreallodape, new genus ...... 78 Subfamily Apinae Latreille ...... 86 Tribe Electrobombini, new tribe ...... 88 Genus Electrobombus, new genus ...... 88 Tribe Electrapini Engel ...... 90 Genus Electrapis Cockerell ...... 92 Genus Protobombus Cockerell ...... 99 Genus Thaumastobombus, new genus ...... 109 Tribe Melikertini, new tribe ...... 112 Genus Succinapis, new genus ...... 115 Genus Melikertes Engel ...... 123

3 4 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Genus Melissites, new genus ...... 129 Genus Roussyana Manning ...... 131 Tribe Meliponini Lepeletier de Saint Fargeau ...... 133 Genus Kelneriapis Sakagami ...... 134 Genus Liotrigonopsis, new genus ...... 135 Apoidea Incertae Sedis ...... 137 Genus and Species Indeterminate ...... 137 Missing Taxa of Uncertain Identity ...... 138 Cladistic Analyses ...... 139 Lithurginae ...... 139 Xylocopinae ...... 140 Corbiculate Apinae ...... 142 Discussion ...... 150 Origin of Bees ...... 150 The Eocene Bee Fauna ...... 159 Epilogue ...... 161 Acknowledgments ...... 161 References ...... 162 Appendix 1: Bees in Amber and Copal ...... 175 Appendix 2: Tribal Classi®cation and Geological Distribution of Bees ...... 177 Appendix 3: Catalog of Family- and Genus-Group Names for Fossil Bees ...... 180 Appendix 4: Full Titles of Journals Abbreviated in References ...... 182 Index of Taxonomic Names ...... 185 Color Plates ...... 186±192 2001 ENGEL: BALTIC AMBER BEES 5

ABSTRACT

The bees found as Baltic amber inclusions are revised and the history of studies on these fossils is brie¯y reviewed. In total this subtropical Eocene fauna contains 36 species and 18 genera, all extinct. These are classi®ed here into nine tribes, six subfamilies, and ®ve families of which six tribes and one family are unknown in the modern fauna. The following taxa are described as new to science: PALEOMELITTIDAE, new family; Boreallodapini, Electro- bombini, Eomacropidini, Melikertini, Protolithurgini, new tribes; Ctenoplectrellina, new subtribe; Boreallodape, Electrobombus, Electrolictus, Eomacropis, Glaesosmia, Liotrigon- opsis, Melissites, Paleomelitta, Protolithurgus, Succinapis, Thaumastobombus, new genera; Boreallodape baltica, B. mollyae, B. striebichi, Ctenoplectrella cockerelli, C. grimaldii, Elec- trapis krishnorum, Electrobombus samlandensis, Electrolictus antiquus, Eomacropis glaesaria, Glaesosmia genalis, Glyptapis densopunctata, G. disareolata, Liotrigonopsis rozeni, Melikertes clypeatus, Melissites trigona, Paleomelitta nigripennis, Protobombus basilaris, Protolithurgus ditomeus, Succinapis goeleti, S. micheneri, S. proboscidea, Thaumastobom- bus andreniformis, new species (seven new family-, 11 new genus-, and 22 new species- group taxa). The genus Electrapis is found to be paraphyletic and the subgenera Melikertes, Roussyana, and Protobombus are given generic status outside of Electrapis. The subtribe Electrapina is elevated to tribal rank among the corbiculate Apinae and the subfamily Glyp- tapinae of Cockerell is reduced to subtribal rank within Osmiini. The genera Chalcobombus and Sophrobombus are newly synonymized with Protobombus. Glyptapis reducta Cockerell is synonymized with G. fuscula Cockerell, Electrapis minuta Kelner-Pillault with Apis palmnickenensis Roussy, Ctenoplectrella splendens Kelner-Pillault and C. dentata Salt both with C. viridiceps Cockerell, Electrapis apoides Manning and Chalcobombus humilis Cockerell both with Protobombus indecisus Cockerell, and Electrapis bombusoides Kelner-Pillault with E. tornquisti Cockerell (new synonymies). The following new combinations are proposed: Electrapis martialis (Cockerell), Melikertes proavus (Menge), M. stilbonotus (Engel), Kelner- iapis eocenica (Kelner-Pillault), Protobombus fatalis (Cockerell), P. hirsutus (Cockerell), and Electrapis martialis (Cockerell) (new combinations). A lectotype is designated for Electrapis minuta Kelner-Pillault and neotypes designated for Apis meliponoides Buttel-Reepen, A. palmnickenensis Roussy, Chalcobombus humilis Cockerell, C. hirsutus Cockerell, C. martialis Cockerell, Ctenoplectrella dentata Salt, C. viridiceps Cockerell, Electrapis tornquisti Cock- erell, Glyptapis reticulata Cockerell, G. neglecta Salt, Protobombus indecisus Cockerell, P. tristellus Cockerell, and Sophrobombus fatalis Cockerell. The subfamily Xylocopinae is recorded for the ®rst time from amber, and the families Halictidae and Melittidae are con®rmed as occurring in Baltic amber. The oldest fossils of the Halictidae, Megachilidae (Lithurginae and Megachilinae), Melittidae, and Xylocopinae are reported and described herein. Keys are presented for the identi®cation of the Baltic amber bees. Three new recent taxa are also proposed: Penapini, Redivivini, and Meliturgulini (new tribes). Cladistic analyses of the Lithurginae, Xylocopinae, and corbiculate Apinae are presented. Preliminary investigation of lithurgine relationships demonstrates that the fossil, Protolithur- gus, is sister to extant genera of the subfamily and that Lithurgus s.s. is likely paraphyletic with respect to Lithurgopsis and Microthurge. Xylocopine relationships are generally in accord with those previously proposed: Xylocopini sister to all other tribes and Manueliini sister to the abruptly narrowed mandible tribes (i.e., Ceratinini, Allodapini, and Boreallodapini). Bo- reallodapini, despite some apparently apomorphic similarities with Ceratinini, is supported as sister to Allodapini. The paleontological evidence for corbiculate bee phylogeny reinforces traditional concepts over relationships of these tribes and contradicts recent molecular studies. Two extinct corbiculate tribes are based on specimens that exhibit worker morphologies indicative of advanced eusocial behavior and are related to the living, advanced eusocial tribes Apini and Meliponini, supporting a hypothesis of a single origin for this behavioral characteristic. The composition of the Eocene bee fauna of Europe is discussed. The fauna is predomi- nantly composed of long-tongued bees, but some short-tongued bees are represented in the families Halictidae, Paleomelittidae, and Melittidae. Bees in Baltic amber are generally allied with groups currently inhabiting sub-Saharan Africa and southeast Asia, a biogeographic pattern common to many Baltic amber groups. The phylogeny and origin of bees are discussed. The bees are a derived, monophyletic 6 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

group of the spheciform wasps and presumably arose sometime in the earliest mid-Cretaceous after the origin of angiosperms. Reports of bees from Jurassic strata or earlier are all refuted. All available evidence supports the idea that bees originated shortly after ¯owering plants and diversi®ed into higher lineages contemporaneously with the radiations of angiosperms. Major bee lineages (i.e., families) were thus presumably established by the Late Cretaceous. A catalog of bees presently known in amber and copal is appended as is a catalog of family- and genus-group names for fossil bees (both amber inclusions and compression fossils). A preliminary outline of the tribal classi®cation of Recent and fossil bees with their geological distribution is presented (with three new family-group taxa for living bees).

ZUSAMMENFASSUNG Die als Inklusen des Baltischen Bernsteins nachgewiesenen Bienen werden revidiert und ihre Erforschungsgeschichte kurz dargestellt. Insgesamt umfasst diese subtropische Fauna des EozaÈns 36 Arten und 18 Gattungen, die alle ausgestorben sind. Diese werden in neun Tribus, sechs Unterfamilien, und fuÈnf Familien klassi®ziert, von denen sechs Tribus und eine Familie in der heutigen Fauna unbekannt sind. Die folgenden Taxa sind neu fuÈr die Wissenschaft: PALEOMELITTIDAE, fam. nov.; Boreallodapini, Electrobombini, Eomacropidini, Me- likertini, Protolithurgini, tribus nov.; Ctenoplectrellina, subtribus nov.; Boreallodape, Elec- trobombus, Electrolictus, Eomacropis, Glaesosmia, Liotrigonopsis, Melissites, Paleomelitta, Protolithurgus, Succinapis, Thaumastobombus, gen. nov.; Boreallodape baltica, B. mollyae, B. striebichi, Ctenoplectrella cockerelli, C. grimaldii, Electrapis krishnorum, Electrobom- bus samlandensis, Electrolictus antiquus, Eomacropis glaesaria, Glaesosmia genalis, Glyp- tapis densopunctata, G. disareolata, Liotrigonopsis rozeni, Melikertes clypeatus, Melissites trigona, Paleomelitta nigripennis, Protobombus basilaris, Protolithurgus ditomeus, Succi- napis goeleti, S. micheneri, S. proboscidea, Thaumastobombus andreniformis, spec. nov. (sieben neue Familien-, 11 neue Gattungs-, und 22 neue Artengruppentaxa). Die Gattung Electrapis ist paraphyletisch, und die Untergattungen Melikertes, Roussyana, und Protobom- bus werden unabhaÈngig von Electrapis als Gattungen akzeptiert. Die Untertribus Electrapina erhaÈlt den Rang einer Tribus innerhalb der corbiculaten Apinae, und die Unterfamilie Glyp- tapinae von Cockerell wird als Untertribus innerhalb der Osmiini interpretiert. Die Gattungen Chalcobombus und Sophrobombus werden neu mit Protobombus synonymisiert. Folgende Arten werden miteinander synonymisiert: Glyptapis reducta Cockerell mit G. fuscula Cock- erell, Electrapis minuta Kelner-Pillault mit Apis palmnickenensis Roussy, Ctenoplectrella splendens Kelner-Pillault und C. dentata Salt beide mit C. viridiceps Cockerell, Electrapis apoides Manning und Chalcobombus humilis Cockerell beide mit Protobombus indecisus Cockerell, Electrapis bombusoides Kelner-Pillault mit E. tornquisti Cockerell (neue Synon- yme). Die folgenden Kombinationen werden neu eingefuÈhrt: Electrapis martialis (Cockerell), Melikertes proavus (Menge), M. stilbonotus (Engel), Kelneriapis eocenica (Kelner-Pillault), Protobombus fatalis (Cockerell), P. hirsutus (Cockerell), und Electrapis martialis (Cockerell) (neue Kombinationen). Ein Lectotypus wird fuÈr Electrapis minuta Kelner-Pillault festgelegt. FuÈr folgende Arten werden Neotypen designiert: Apis meliponoides Buttel-Reepen, A. palmnickenensis Roussy, Chalcobombus humilis Cockerell, C. hirsutus Cockerell, C. martialis Cockerell, Ctenoplectrella dentata Salt, C. viridiceps Cockerell, Electrapis tornquisti Cock- erell, Glyptapis reticulata Cockerell, G. neglecta Salt, Protobombus indecisus Cockerell, P. tristellus Cockerell, und Sophrobombus fatalis Cockerell. Die Unterfamilie Xylocopinae wird erstmals in Bernstein nachgewiesen, und das Vorkommen der Familien Halictidae und Mel- ittidae in Baltischem Bernstein wird bestaÈtigt. Die aÈltesten Fossilien der Halictidae, Megach- ilidae (Lithurginae und Megachilinae), Melittidae, und Xylocopinae werden nachgewiesen und beschrieben. BestimmungsschluÈssel fuÈr die Bienen des Baltischen Bernsteins werden erstellt. Drei rezenten Taxa sind neu: Penapini, Redivivini, und Meliturgulini (tribus nov.). Kladistische Analysen der Lithurginae, Xylocopinae, und der corbiculaten Apinae werden vorgestellt. VorlaÈu®ge Untersuchungen der verwandtschaftlichen Beziehungen der Lithurgi- nae zeigen, dass die fossile Protolithurgus Schwestergruppe der rezenten Gattungen der Li- thurginae ist. Auûerdem ist Lithurgus s.s. wahrscheinlich paraphyletisch in Bezug auf Li- thurgopsis und Microthurge. Die Verwandtschaftsbeziehungen der Xylocopinae stimmen grundsaÈtzlich mit den bisher angenommenen uÈberein: Die Xylocopini sind die Schwester- 2001 ENGEL: BALTIC AMBER BEES 7

gruppe aller uÈbrigen Tribus, waÈhrend die Manueliini die Schwestergruppe aller Tribus mit Arten mit abrupt verschmaÈlerten Mandibeln ist (z.B. Ceratinini, Allodapini, und Boreallo- dapini). Boreallodapini wird als Schwestergruppe der Allodapini begruÈndet, abgesehen von einigen anscheinend apomorphen AÈ hnlichkeiten mit den Ceratinini. Die palaÈontologischen Indizien stuÈtzen traditionelle Konzepte der phylogenetischen Beziehungen der corbiculaten Bienen und widersprechen neueren molekularen Untersuchungen. Die Arbeiter zweier fossiler, corbiculater Tribus zeigen morphologische Merkmale, die auf stark abgeleitetes euso- ziales Verhalten hindeuten: Diese Tribus sind offenbar mit den rezenten, hoch-eusozialen Tribus Apini und Meliponini verwandt, was die Hypothese der einmaligen Entstehung dieses Verhaltensmerkmals unterstuÈtzt. Die Zusammensetzung der eozaÈnen Bienenfauna wird diskutiert. Sie besteht vorwiegend aus langzuÈngigen Bienenarten, auch wenn einige kurzzuÈngige Arten der Familien Halictidae, Paleomelittidae, und Melittidae ebenfalls vertreten sind. Im Allgemeinen sind die Bienen des Baltischen Bernsteins mit rezenten Bienen des Afrikas suÈdlich der Sahara und SuÈdostasiens verwandt; ein bei Organismen des Baltischen Bernsteins haÈu®ges biogeographisches Muster. Die Phylogenie und der Ursprung der Bienen werden diskutiert. Die Bienen sind eine abgeleitete, monophyletische Gruppe der spheciformen Wespen und entstanden irgendwann in der fruÈhesten Mittelkreide nach der Entstehung der Angiospermen. Nachweise von Bienen aus dem Jura oder noch fruÈher werden widerlegt. Alle verfuÈgbaren Indizien stuÈtzen die An- nahme, dass die Bienen kurz nach den BluÈtenp¯anzen entstanden und in ihre grundsaÈtzliche Diversi®kation parallel zur Angiospermenradiation erfolgte. Die groûen Linien der Bienen (z.B. Familien) waren daher in der spaÈten Kreide bereits vorhanden. Ein Katalog der in Bernstein und Kopal nachgewiesenen Bienen und ein Katalog der Familien- und Gattungsgruppennamen fossiler Bienen (sowohl aus Bernstein wie aus Sedi- menten) wird vorgestellt. Eine vorlaÈu®ge Idee einer Klassi®kation der rezenten wie fossilen Bienen auf Tribus-Niveau mit ihrer geologischen Geschichte wird entwickelt (mit drei neuen Familiengruppennamen fuÈr rezente Bienen).

``Et latet, et lucet PhaeÈtontide condita gutta, ¯owers teeming with the gentle murmur of Ut videatur apis nectare clausa suo; benevolent pollen harvesters at their labors. Dignum tantorum pretium tulit illa laborum, Bees have instilled within us ideal notions of 1 Credible est ipsam sic voluisse mori.'' industriousness, loyalty, obedience, and sac- ÐM. V. Martialis, Epigrammata, ri®ce not through denigration but through al- ca. 89 anno domini most holy reverence to a greater good. Even the famous parable from the Bible (Proverbs MONOGRAPHIA APUM SUCCINI BALTICI 6) teaching us to ``go to the ant'' originally included reference to the labors of bees2. INTRODUCTION Such emotions and concepts connected to bees ¯ow through our common natural her- Bees occupy a unique role in the world of itage; even the great ``Mother Goddess'' un- arthropods. They are entwined into most as- covered at the root of most Western religions pects of human culture and mythology, not was symbolized by a bee. to mention our agriculture, economy, and More signi®cant, perhaps, than their per- general ecology. Mention of their name in- vasiveness in human society is that bees stantly recalls a suite of images and senses serve as the most signi®cant pollinators of tying together warm days, sunny skies, soft ¯owering plants, helping to sustain and un- breezes, and ®elds of fragrant and colorful derpin major ecological systems worldwide

1 Translation: ``Now dim, now bright, trapped in its 2 ``Go to the bee, and learn how diligent she is, and amber tear, / A bee seems sealed in its own nectar clear; what a noble work she produces, whose labors kings and / For a life of endless toil, most ®tting pay /ÐSurely a private men use for their use, she is desired and honored bee would wish to die this way!'' // Martial's PhaeÈthontis by all, and though weak in strength she values wisdom or ``amber tear'' is a reference to the myth of Phaeton, and prevails.'' Proverbs, Chapter 6, Septuagint version who died when he tried to drive the chariot of the sun (i.e., the oldest Greek version and perhaps the oldest across the sky. Phaeton's sisters wept and their tears extant version) of the Holy Bible (see also Engel, 2000a: turned to amber. Translation courtesy V. Krishna. 2). 8 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

(e.g., Moldenke, 1976; Arroyo et al., 1982; family. These deposits have been dated at ap- Bawa et al., 1985; Bawa, 1990; Petanidou proximately 34.1 Ma (Epis and Chapin, and Vokou, 1990; Buchmann and Nabhan, 1974), placing them near the Eocene-Oligo- 1996; Proctor et al., 1996). The bees are also cene boundary, and are conservatively treat- arguably one of the more diverse groups of ed as early Oligocene herein. Work on the pollinators, with a standing diversity of ca. bees of these deposits is ongoing. 20,000 species. A phylogenetic study of the DOMINICAN AMBER: Bees in Dominican fossil record is crucial to understanding how amber can be quite common; worker speci- this modern diversity came to be, as well as mens of Proplebeia dominicana (Wille and for identifying the periods of diversi®cation Chandler) number into the thousands and can and extinction, reconstructing historical zooÈ- be frequently purchased in gem and mineral geography, and uncovering the sequence and shops at no great expense. All other bee origin of synapomorphies (e.g., Patterson, groups from these deposits are known on the 1981; Grande, 1985; Eldredge and Novacek, basis of but a few individuals, often only 1985; Donoghue et al., 1989; Novacek and one. Through a series of recent papers this Wheeler, 1992; Grimaldi, 1992). The study fauna has been essentially revised. Table 1 of fossil bees, or paleomelittology3, is still in summarizes the Miocene bee fauna of His- its infancy and a complete synthesis of fossil paniola as it is presently understood. This pa- and living taxa has yet to be achieved. The leofauna is quite modern in character. Most present work is one of a series of attempts to species are representative of extant genera, unite paleomelittology with the systematics although several are today locally extinct of living bees into a meaningful whole. Fos- from the West Indies (e.g., Heterosarus, Neo- sils of bees are rare compared to some other corynura, Chilicola, Meliponini) or from insect groups; the few known specimens are Hispaniola (e.g., Euglossa, Eufriesea). Those typically discovered in isolation, and scat- few Dominican amber genera that are extinct tered in sites around the world. Three depos- are remarkably similar to living forms. All its, however, have produced sizeable bee pa- groups are easily placed in living subtribes, leofaunas. tribes, and other higher categories. FLORISSANT,COLORADO: Fossils from The age of the Dominican amber mines Florissant, Colorado, are compressions with has been of some controversy. Lambert et al. virtually no relief, and were formed in ®ne (1985) suggested a range of ages from Eo- volcanic ash over several millions of years cene to Miocene based on NMR analyses. of repeated eruptions. Preservation at Flor- Grimaldi (1995), however, argued that Do- issant can be quite ®ne, but those bees dis- minican amber had to be younger than the covered to date typically preserve only the Eocene and Oligocene dates, while Iturralde- wing venation or some structures of the legs, Vinent and MacPhee (1996, 1999) later pro- so meaningful comparisons with other de- vided a strong stratigraphic basis for an early posits or living taxa are not possible. Bees Miocene age. This geological evidence is have been described from the families Hal- also consistent with the inclusions in Domin- ictidae, Andrenidae, Melittidae, Megachili- ican amber that are modern not only in gen- dae, and Apidae (Cockerell, 1906, 1908a, eral appearance but also in cladistic position 1908b, 1908c, 1909d, 1909e, 1911a, 1911b, (e.g., bees discussed brie¯y above; for ¯ies 1913a, 1913b, 1914, 1917, 1923, 1925), al- see Grimaldi, 1995). though those of the Melittidae, Andrenidae, BALTIC AMBER: The middle Eocene am- and some Apidae are dubiously assigned to ber of northern Europe was previously believed to contain merely a handful of speci- 3 The word paleomelittology, admittedly of my own mens of rather rare and enigmatic bee species creation, is introduced here for the ®rst time. It is derived (e.g., Cockerell, 1908b, 1909b, 1909c; Zeu- from the Greek words ␲␣␭␣␫␱␨ (palaios, meaning ``an- ner and Manning, 1976). Although the few cient''), ␮⑀␭␫␶␶␣ (melitta, meaning ``bee''), and ␭␱␥␱␨ bees were recognized to be of phylogenetic (logos, suf®x denoting ``knowledge of''). It can be de- ®ned as: (noun) the science of fossil bees; a branch of import, the general paucity of material and knowledge that deals with bees of past geological peri- the loss of several type specimens deterred ods. meaningful work on the deposit. Through 2001 ENGEL: BALTIC AMBER BEES 9

TABLE 1 Bee Fauna of Miocene Dominican Amber (Updated from Engel, 1999d) 10 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 diligent efforts over the past three years I TABLE 2 have managed to increase the number of Hierarchical Supraspeci®c Classi®cation of known specimens by nearly sevenfold and, Baltic Amber Bees as will be shown in the following pages of (Number of named species in this monograph, the Baltic amber bee fauna each genus-group indicated) is in actuality the most diverse extinct bee fauna known (summarized in table 2). Al- though I have increased the number of known individuals and species signi®cantly, bees are still quite rare in Baltic amber, with only one specimen appearing among approximately every 5000 inclusions. Naturally, as work continues the number of specimens will grow steadily. I will be interested in examining new material as it becomes available for the production of supplements to this work. Since this monograph concerns itself expressly with the Baltic fauna, a discussion of the age of this amber is presented below (refer to Age and Origin of Amber). Various other Cenozoic sites have produced bees (e.g., Late Cretaceous amber from New Jersey, Oligocene-Miocene amber of Mexico, Miocene compression from Ja- pan, sundry Eocene through Miocene compression fossils in Europe and North Amer- ica), and although work is continuing on these and other deposits (e.g., Engel, 1998c, 2000b, unpubl. data), none have at present revealed the number of individuals or diversity of bees exhibited by the above three lo- cales. Moreover, most of these are compression fossils. If we seek to explore the implications of fossil taxa on our knowledge of bee evolution in general, then direct comparisons are required between often tiny or obscure morphological traits; such features are rarely preserved in even the ®nest of compression fossils. Amber, however, is unri- valed in the paleontological realm for its ability to preserve ®ne details (including internal tissues; e.g., Grimaldi et al., 1994) and so from at least those fossils of the Domin- ican Republic and the Baltic region we can begin to seek the necessary character information for comparison and eventual cladistic study. A further limitation arises, however; only one of the two major amber sites (i.e., Baltic amber; not surprisingly the older of the two deposits) has revealed taxa that are not essentially modern. As brie¯y mentioned above, the bees of the lower Miocene found as inclusions from the Dominican Republic 2001 ENGEL: BALTIC AMBER BEES 11 fall nicely into extant genera or into genera but the living fauna was considered on a closely allied to living groups. Thus, al- global scale. Moreover, many of the fossils though providing valuable information on lo- have been included in cladistic studies with cal West Indian paleomelittology, extinc- living groups so as to better de®ne their af- tions, and patterns of historical biogeogra- ®nities to known lineages and the validity of phy, Dominican taxa contribute little to our basing taxa on their peculiar character com- knowledge of bee phylogeny. In fact, a gen- binations. This has manifested itself most no- eral comparison (of all deposits) of bees from tably for the corbiculate Apinae. Numerous the Oligocene to the present day shows very fossils of this clade occur in Baltic amber, little difference in the fauna at the generic or and owing to the controversy concerning re- higher levels (refer to Discussion, below). lationships among Recent corbiculates (e.g., Early statements pertaining to Baltic am- Schultz et al., 1999), it has been particularly ber bees were tantalizing: ``With the general critical to document the morphology and cla- form of Apis [honey bees], it has venation distic implications of the extinct corbiculate nearer to that of Bombus [bumble bees]...'' taxa (Engel, 2000c). As a result of this body (Cockerell, 1909b: 8). Observations like of work, the classi®cation of Baltic amber these, combined with the much older age of bees has been radically altered (table 3). Baltic amber, make a study of those taxa all A recent classi®cation of the bees (Mich- the more enticing and critical. Now, with so ener, 2000a) recognized seven extant fami- many more Baltic specimens at hand, it is lies: Colletidae, Stenotritidae, Halictidae, possible to con®rm the observations of ear- Andrenidae, Melittidae, Megachilidae, and lier authors, to add numerous newly discov- Apidae. The classi®cation presented here ered lineages to the list of known taxa, to also recognizes seven families in total but carefully and systematically describe such differs in two major groupings from that pro- peculiar groups, to explore the phylogenetic posed by Michener (2000a). The family implications of these taxa, and to make more Stenotritidae is a clade of Colletidae and ren- general observations and hypotheses on the ders the latter paraphyletic; as mentioned origin, diversi®cation, and evolution of the elsewhere (e.g., Engel, 2000a: 5), I consider bees. As the following pages demonstrate, Stenotritus and Ctenocolletes to form a sub- the Baltic amber bee fauna is the best doc- family of Colletidae, although stenotritines umented paleofauna for bees, the most di- should perhaps be further demoted to tribal verse (in both numbers of species, genera, rank within Colletinae (or perhaps more ap- and other higher categories), and the most propriately, the latter group should be broken critical for phylogenetically important taxa. into several subfamilies). Furthermore, I The Baltic amber is the oldest deposit in the have recognized a new family from the fossil world with a bee fauna of any sizeable sig- record (described below) that is intermediate ni®cance. in character between the basic short-tongued This work is, in essence, a faunal revision, families and a clade consisting of Melittidae the area under consideration being the Baltic and the long-tongued bees. Lastly, with re- region of 45 million years ago. As with any gard to the familial classi®cation, I believe faunal revision there is concern over whether suf®cient evidence exists for Melittidae or not the author took a global view when monophyly so as to retain it as a single fam- delimiting groups and thereby avoided pro- ily, thereby avoiding the proliferation of posing synonyms for taxa well characterized ``melittoid'' families suggested by Alexander outside of the limited geographic scope of and Michener (1995: Melittidae s.s., Dasy- the work. I hope to eliminate this potential podaidae4, and Meganomiidae). Appendix 2 criticism at the start by stating that, although along with ®gures 122 and 123 summarize dealing with a bee fauna that has long since my suprageneric classi®cation of bees as it vanished from the Earth, I took an exhaustive geographic and temporal perspective when 4 The original spelling for this subfamily, Dasypodi- nae, has been emended in order to remove homonymy analyzing these fossils. Not only were fossils with the family-group name for armadillos (Mammalia: studied from all existing deposits containing Xenarthra: Dasypodidae) (Alexander et al., 1998; ICZN, bees (of all ages, Cretaceous to Pleistocene!), 1999a). 12 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

TABLE 3 Comparison of Present Classi®cation with Earlier Usage 2001 ENGEL: BALTIC AMBER BEES 13 presently stands; more detailed studies and diligent search it appears that only one of his further re®nements will be presented else- specimens has survived to the modern day, where. this being his Apis proava (treated below as Melikertes proavus). Owing to the misplace- HISTORICAL REVIEW ment of this species, even following the taxonomic conventions of his time, Menge's re- Baltic amber has had a long association maining species must be considered dubi- with humans, perhaps more so than any other ously assigned as to genus. Motschulsky amber deposit. The ®rst Baltic amber bees (1856), working at the same time, recorded were simply mentioned rather than described a specimen of `Àndrena'' and proposed the or studied in any detail. Authors of antiquity genus and species Bombusoides mengei; the regularly referred to amber and insect inclu- latter becoming the ®rst new genus-group sions and, owing to the already tight bond proposed for the fauna and the ®rst recog- between bees and man by the Hellenic and nition of an extinct supraspeci®c lineage Roman eras, it is little wonder that even fos- from the Baltic amber. Brischke (1886) later sil bees would appear in their literature (e.g., identi®ed what he considered to be Andrena, the poem at the opening of this monograph; Chalicodoma, Anthophora, Melipona, and the work of Ausonius). Bombus in Baltic amber, but none were given Burmeister (1831, 1832) seems to have names. Like much of Menge's material, the been the ®rst researcher to comment on the specimens examined by Burmeister, Bris- presence of bees in Baltic amber after the chke, and Motschulsky have been presum- standardization of binomial nomenclature by ably lost. All of these authors, except, of Linnaeus (1758). In his works he refers to a course, Motschulsky, placed the specimens ``Trigona'' similar to South American spe- before them into Recent genera and species cies. None of his material has survived to the groups. None of the identi®cations by these present day; however, individuals of the me- authors can be considered entirely accurate likertine bees have a general habitus strongly and should not be relied upon for determin- reminiscent of Trigona species and it is posing the presence of a particular living bee sible Burmeister had one of these bees before genus in Baltic amber nor for placing a mid- him. Hope (1836) also mentioned bees in his dle Eocene age on any of these same genera. private collection of Baltic amber insects as Buttel-Reepen (1906) was the ®rst re- well as in the collections of his correspon- searcher of the last century to systematically dents. Hope referred in his synopsis of amber study a Baltic amber bee as part of his larger insects to specimens of `Àndrena'', `Àpis'', monograph on the honey bees of the world. and ``Trigona'' (the latter two perhaps in- In his study, Buttel-Reepen described a Bal- cluded specimens of Electrapini and Meli- tic amber fossil as A. meliponoides and con- kertini, respectively, or were actually living sidered it as intermediate between the honey taxa preserved in copal5). bees (tribe Apini) and their sisters, the sting- Menge (1856) was the ®rst to describe less bees (tribe Meliponini); hence his choice some of the forms he had before him as new of a speci®c epithet. Apis meliponoides, de- species of extant genera, naming species of spite Buttel-Reepen's contention, does not ®t what he believed to be Apis and Bombus. In into this position (see below), although there addition, Menge referred to individuals of are indeed Baltic amber fossils that appear Anthophora, Dasypoda, and Osmia, although intermediate in some characters between Ap- he did not give them speci®c names. After a ini and Meliponini and strengthen their sister-group relationship supported by numer- 5 Examination of surviving material from Hope's collection in the University Museum, University of Oxford, ous authors (e.g., Engel, 1998d; Noll, 1998; has revealed only specimens of extant Hypotrigona and Schultz et al., 1999, and references therein). one Heriades in African copal (mistakenly identi®ed as Cockerell was the next individual to un- succinite). It is possible that all of Hope's original ma- dertake a study of the Baltic amber bees and terial was actually copal, although that material he reports on from his contemporaries' collections certainly in far greater depth than Buttel-Reepen, who included true Baltic amber. I am grateful to C. O'Toole was primarily interested in Apis. In a series for a loan of this interesting material. of papers published in 1908 and 1909, Cock- 14 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 erell described the majority of the Baltic am- gen as indicated in Kelner-Pillault's paper; ber bees known until the completion of the the type was actually in Berlin]. All of this present study. Cockerell was intimately fa- information has been corrected below. miliar with the world bee fauna and was the The last major work on the Baltic amber ®rst to recognize the signi®cance of the Bal- fauna was as part of a larger attempt to tic amber bees, attempting, in a very rudi- monograph all fossil bees (Zeuner and Man- mentary way, to explore the implications of ning, 1976). This work was compiled from these taxa on apid evolution (e.g., Cockerell, accumulated notes more than a decade after 1908b) (®g. 120). the deaths of the authors and as such unfor- Subsequent to Cockerell only a few work- tunately suffers from a number of errors. ers have attempted to study the Baltic amber Most of their monograph does not present bees, none in great detail. Only two small original information and often the sections papers appeared between the work of Cock- for a given taxon are merely taken from the erell and a small outburst of activity in the original descriptions. This is particularly true 1970s. Salt (1931) proposed new species of for the Baltic amber bees. In several instanc- Glyptapis and Ctenoplectrella as well as a es it is all too apparent that neither had ever species he believed to be an Andrena (see seen specimens of particular taxa (e.g., see Apoidea Incertae Sedis, below), while Man- sections on Ctenoplectrella and Glyptapis, ning (1960) described a new species of what below). Moreover, in their work some taxa he believed to be Electrapis along with a have been incorrectly diagnosed owing to a new subgenus. Outside of these two works, failure to examine types (e.g., A. henshawi; systematic study of bee inclusions from the see Engel, 1998c), and the authorship attri- Baltic stagnated for about one-half of a cen- buted to numerous groups is wrong. Re- tury. It was not until the papers of Kelner- searchers should be mindful of these dif®- Pillault, late curator of Hymenoptera at the culties and proceed with caution when at- Museum National d'Histoire Naturelle, that tempting to use their monograph. Had both scienti®c study of this fauna resumed, al- Zeuner and Manning lived longer, the study though for only a very short while. Kelner- doubtless would have been a more accurate Pillault engaged herself in ®ve short studies and bene®cial work. of bees from these deposits. Although her Since the 1970s almost nothing has ap- work was adequate, she did not attempt to question previous studies nor to compare her peared on the Baltic amber bee fauna. Of the material to prior descriptions, thereby forcing minor references to Baltic amber bees in re- her specimens into new taxa within groups cent literature only two papers deserve men- as de®ned by earlier authors. Curiously, Kel- tion. Both Gerlach (1989) and Engel (1998a) ner-Pillault published erroneous information presented short notes on small collections of for the type depositories of species she de- specimens. Gerlach (1989) reported three scribed (e.g., Kelner-Pillault, 1970a, 1970b). specimens misidenti®ed as Dasypoda, Me- In her papers she regularly refers her material gachile, and Apis (identi®cations corrected to the Institut und Museum fuÈr Geologie und herein as Glyptapis, Ctenoplectrella?, and PalaÈontologie in GoÈttingen, when nearly all Electrapis, respectively), while Engel of her material is in the Institut fuÈr PalaÈon- (1998a) described a new species and subge- tologie, Museum fuÈr Naturkunde, in Berlin. nus in Electrapis and commented on the clas- It cannot be that the specimens were simply si®cation of the genus as it was understood sent to the wrong institution after publica- at that time (that classi®cation is radically al- tion, since each is accompanied by older la- tered herein). Although reference to the enig- bels that catalog them as belonging to Berlin matic nature of Baltic amber bees has often (and these are often quoted by Kelner-Pillault been made (e.g., Winston and Michener, in her papers). This unfortunate confusion is 1977; Michener, 1990; Engel, 1998a), as well the reason it has been dif®cult for other as the desperate need for a critical revision workers to locate and study her material and reexamination of the fauna (e.g., Lutz, [e.g., Michener (1990) records that he was 1993), the ®eld has remained essentially un- unable to locate Trigona eocenica in GoÈttin- touched. 2001 ENGEL: BALTIC AMBER BEES 15

The present work is an attempt to mono- others. Tragically, Albertus UniversitaÈt suf- graph this unique fauna of bees, to explore fered, alongside millions of people and other its implications for understanding higher-lev- cultural institutions, during the second World el af®nities of apoid taxa, and to consider War, and the collection was mostly de- general evolutionary patterns of the bees in- stroyed, although some surviving specimens clusive of their early origins. This is the ®rst were scattered for safekeeping. Today, the comprehensive treatment of a fossil bee fau- largest surviving portion from KoÈnigsberg's na and is part of a series of papers by the collection is located in the Institut und Mu- present author to monograph the fossil bees seum fuÈr Geologie und PalaÈontologie in GoÈt- of the world, ultimately aimed at unifying tingen, although it is still only a fraction of paleomelittology with our neontological the original collection's size. knowledge of bees. Future revisions of this Baltic amber occurs in the blau Erde monograph will undoubtedly be needed as (``blue Earth''), which, as mentioned above, new or more perfectly preserved specimens occurs throughout northern Europe approxi- are discovered. For the present, however, I mately 45 m below the surface and runs ca. hope that this work will provide a foundation 5 m below sea level. Thus, exposed deposits for paleoentomological studies of bees. A can erode out and wash amber up on shores catalog and bibliography of the fossil bee not only of the Baltic countries but as far species of the world (both amber inclusions away as the eastern coasts of England. The and compression fossils) is currently in prep- formation continues under the Baltic sea aration (Engel, in prep.), while a catalog of ¯oor. Stratigraphic studies of the blau Erde family- and genus-group names for fossil indicate it to be middle Eocene in age (Kos- bees is appended at the end of this work (ap- mowska-Ceranowicz, 1987; Kosmowska- pendix 3). Ceranowicz and MuÈller, 1985). The stratigraphic dates correlate perfectly with recent AGE AND ORIGIN OF AMBER K-Ar radiometric studies (Ritzkowski, 1997), all of which indicate that Baltic amber is Although pockets of Baltic amber can be 44.1Ϯ1.1 Ma, placing it in the middle of the found throughout northern Europe (e.g., Lutetian stage of the Eocene Epoch. The Bit- Denmark, Sweden, Germany, Poland, and terfeld amber (or Saxonian amber) from Ger- Lithuania, among other countries), the great- many is actually contemporaneous with Bal- est concentration, and where most material tic amber and similar in both chemical com- originates, occurs on the Samland Peninsula position and inclusions of the fauna and ¯ora (historically part of Prussia but today occu- (e.g., Schumann and Wendt, 1989; RoÈsch- pied by Russia). The city of KoÈnigsberg (to- mann and Mohrig, 1995). This Eocene amber day Kaliningrad), situated near the base of occurs in Miocene strata and has therefore the Samland Peninsula, once held the most been considered to be much younger than signi®cant and largest collection of Baltic true Baltic amber; however, it has been dem- amber inclusions owing to the proximity of onstrated that Bitterfeld amber has been re- the richest deposits. The Albertus UniversitaÈt deposited at least twice during its geological in KoÈnigsberg was estimated to hold some history (Weitschat, 1997). Bitterfeld amber 100,000 inclusions at one time. This material is, in essence, Baltic amber that has been was actively studied for a number of years, eroded and redeposited in Miocene forma- particularly by the KoÈniglichen Physikalisch- tions. A few of the inclusions studied herein OÈ konomischen Gesellschaft (Royal Physical are in Bitterfeld amber and are identical to Economy Society), which began publishing taxa from true Baltic amber (see below). special works on Baltic amber in 1860 and Pieces of Baltic amber can be readily iden- continued until 1938. Signi®cant works on ti®ed by a number of diagnostic features. The insect inclusions were produced for ants succinic acid content of most Baltic amber is (Wheeler, 1914), apterygotes (Olfers, 1907; relatively high (ca. 8%); this is the reason it Silvestri, 1912), and, of course, the studies is commonly referred to as succinite. Some by Cockerell (1909b, 1909c) on bees, among more rare deposits, however, either lack suc- 16 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 cinic acid (e.g., glessite, gedanite), or possess port. Among the thousands of inclusions in it in only trace amounts (e.g., beckerite). The Baltic amber are numerous cones and nee- chemical composition of Baltic amber, how- dles of pines (e.g., Weitschat and Wichard, ever, is relatively uniform and diagnostic by 1998) as well as wood fragments with mi- comparison with all other amber deposits. crostructural characters indicative of Pina- Analysis using pyrolysis gas chromatography ceae (Pielinska, 1997; Turkin, 1997). There of Baltic amber produces a diagnostic set of are no araucariaceous inclusions in Baltic peaks (Shedrinsky et al., 1991) and, similar- amber, and all studies of the botanical inclu- ly, infrared spectroscopy analysis produces a sions, particularly those of wood fragments, characteristic absorption spectrum with the have not identi®ed any features distinctive to unique ``Baltic shoulder'' between 1250± Araucariaceae (Agathis, in particular). Enig- 1175 cmϪ1 (Beck et al., 1964, 1965; Beck, matically, most pines today do not produce 1986). Pyrolysis GC analysis of Bitterfeld succinic acid and Baltic amber does not con- amber is identical to that of true Baltic amber tain the abietic acid that today distinguishes (Shedrinsky et al., 1991). Additionally, Bal- pine resin; neither does it contain agathic tic amber frequently includes numerous stel- acid. Recently, however, it has been discov- late trichomes (plant hairs), and inclusions ered that both extant and extinct species of are sometimes covered, either partially or en- the pine genus Pseudolarix produce succinic tirely, in Schimmel (a whitish froth of micro- acid and its resin is chemically very similar scopic bubbles resembling mold: e.g., pl. 7a). to succinite (Anderson and LePage, 1995). Although it has been understood since an- The present day distribution of this genus is tiquity that amber (from northern Europe in in Asia but included at least the Arctic during particular) is the petri®ed resin of ancient the Eocene. It may be highly signi®cant that trees, the botanical origin of Baltic amber is many Baltic amber inclusions have phylo- still debated (although a ®nal solution is per- genetic af®nities with taxa today living in haps on the horizon). Both Pliny the Elder Asia (e.g., see summaries in Larsson, 1978). (in his Natural History) and Tacitus (in his Baltic amber was likely produced by taxa re- Germania), writing around the same time lated to Pseudolarix or even by an extinct during the 1st century, record the ancients' species of this genus. understanding of the resinous origin of am- The Baltic amber forest was, obviously, ber. Tacitus noted that, ``The Germans gather not similar to those forests presently occur- amber but they have not investigated the natural cause or process. . . It is sap [Tacitus's ring in northern Europe. During the middle term] from trees, which can be inferred from Eocene northern Europe was a single land- the fact that you can see creeping things and mass. The remainder of the continent was winged insects which were trapped when the composed of series of large central and substance gradually hardened'', while Pliny southern islands or archipelagos in an ex- further elaborated on the processes producing panded warm sea. This sea led northward amber when he wrote ``Amber is formed of into the Turgai Straits and Obik Sea that at resin seeping from the interior of pine the time separated Europe from northern trees. . . The exudation was hardened by Asia. Africa and India were still well sepa- cold or heat or by the sea. . . That amber rated from Europe and Asia, so most biotic originated as sap is proved by the visible exchange was between the latter two regions, presence of gnats, ants, and lizards trapped although some connections were perhaps inside as it hardened''. Most authors, like possible with North America earlier in the Pliny, have attributed these resins to a mem- Paleocene and earliest Eocene (e.g., McKen- ber of the pine family (Pinaceae) and to the na, 1975). Global climates in the Paleocene extinct species Pinites succinifer GoÈppert and Eocene were signi®cantly warmer than (1836). Although arguments have been made in later Tertiary epochs. The climate in Eu- for Araucariaceae (e.g., Langenheim, 1969; rope in the Eocene was subtropical or tropi- Poinar and Haverkamp, 1985), the pinaceous cal, probably very similar to present day pine hypothesis retains signi®cantly stronger sup- forests in the South Atlantic Coastal Plain of 2001 ENGEL: BALTIC AMBER BEES 17 the United States (i.e., North Carolina to MATERIALS AND METHODS Florida). During an era when human understanding Many institutions throughout the world wrestled vigorously with the idea of biotic maintaining amber collections were contact- and global changes, Rev. Hope (1836) had a ed or visited regarding the presence of un- studied amber bees among their holdings and profound insight into the biogeographical as- the possible location of lost types. Of the mu- sociation of Baltic amber insects and the cli- seums and individuals either contacted or mate of the amber forest. Toward the conclu- visited I was only able to locate material in sion of his paper summarizing, at the generic the following: AMNH, American Museum level, those taxa known to him in succinite of Natural History, Division of Invertebrate he stated: Zoology, New York, New York, David A. Grimaldi; BMNH, The Natural History Mu- From the above discrepancies I abstain at present from entering more largely into the geographical in- seum (British Museum), Department of Pa- vestigation of amber-insects, and reserve it for some laeontology, London, United Kingdom, An- future paper; but from what has already been ad- drew J. Ross; BSPG, Bayerische Staatssa- duced, may we not conclude that the climate and tem- mmlung fuÈr PalaÈontologie und Historische perature of Europe have undergone considerable Geologie, Munich, Germany, Helmut Mayr; change? The above examples of tropical insects suf- ®ciently testify that the amber-tree did not vegetate GPUH, Geologisch-PalaÈontologisches Insti- under a climate such as Prussia now enjoys, but in a tut und Museum, UniversitaÈt Hamburg, warm region. I trust the above notices will afford a Hamburg, Germany, Wolfgang Weitschat; suf®cient stimulus to induce others to take in hand a IMGP, Institut und Museum fuÈr Geologie subject replete with interest; a subject embracing in und PalaÈontologie, GoÈttingen, Germany, its scope not only the changes of temperature and Hans Jahnke; PMUZ, PalaÈontologisches climate which our globe has undergone, but also the consideration of the geographical distribution of in- Museum, UniversitaÈt ZuÈrich, ZuÈrich, Swit- sects and plants, by which alone we can arrive at any zerland; SAMH, Swedish Amber Museum, satisfactory conclusion respecting them. (Hope, 1836: HoÈllviken, Sweden, Leif Brost; ZMHB, Mu- 137). seum fuÈr Naturkunde, Institut fuÈr PalaÈonto- It is not of minor signi®cance that Hope logie, Humboldt-UniversitaÈt, Berlin, Germa- was able to make such broad-reaching con- ny, Erika Pietrzeniuk; ZMPA, Muzeum Zie- clusions concerning global change and zoo- mi Pan, Polska Akademica Nauk, Warsaw, Poland, Barbara Kosmowska-Ceranowicz; geography from even the most cursory study ZMUC, Zoological Museum, University of of Baltic amber inclusions. Copenhagen, Copenhagen, Denmark, Rudolf The transition between the Eocene and Ol- Meier. A single type specimen is deposited igocene Epochs is a well-documented epi- in Paris. Unfortunately, this material was not sode of extinction (e.g., Prothero, 1994). At made available to me for study. The speci- this time global temperatures dropped precip- men is discussed below and the type depos- itously and the geography of the world was itory abbreviated as follows: MNHN, La- signi®cantly altered, particularly for Europe. boratoire d'Entomologie, Museum National As temperatures cooled dramatically toward d'Histoire Naturelle, Paris, France, Andre the end of this epoch the tropical ¯ora and Nel. fauna were gradually extinguished. Likewise, In addition, specimens from the following ocean levels and seaways were altered, personal collections were examined (material bringing the European and Asian continents couriered through W. Weitschat, Geologisch- together and signi®cantly shrinking the PalaÈontologisches Institut und Museum, southern European ocean to create the Med- Hamburg): CCGG, Collection of Carsten iterranean Sea we are more familiar with to- GroÈhn, Glinde, Germany; CDTG, Collection day. Thus, those areas that were once tropical of Dirk Teuber, GuÈtersloh, Germany; CFEG, islands or subtropical mainland forests be- Collection of Friedhelm Eichmann, Hanno- came part of a colder, more temperate, con- ver, Germany; CGHG, Collection of GuÈn- tinual landmass and the ``amber forest'' dis- ther Herrling, Bramsche-Engter, Germany; appeared. CFKG, Collection of F. Kernegger, Ham- 18 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 burg, Germany; CHFG, Collection of C. and In presenting taxonomic summaries for H. Hoffeins, Hamburg, Germany; CHMG, family-group names only those names appli- Collection of Hans Mendl, Kempten, Ger- cable to groups under consideration are pre- many; CJDL, Collection of Jonas Damzen, sented. For example, under the subfamily Vilnius, Lithuania; CJVG, Collection of JuÈr- Megachilinae the nominate tribe is not con- gen Velten, Idstein, Germany; CMGG, Col- sidered in the present monograph owing to lection of Matthias Glink, Buxtehude, Ger- the absence of this group from the Baltic am- many; CMSE, Collection of Michael S. En- ber fauna. The taxonomic history under Me- gel, Lawrence, Kansas, United States; gachilinae therefore presents only the deri- CSUL, Collection of Saulius Urbonas and vation of the family-group name based on Juozas Veilandas, Klaipeda, Lithuania. Al- Megachile and not all of the other names for though his material did not contain any bees valid tribes (e.g., Anthidiini, Dioxyini). Nor (instead, spheciform and chalcidoid wasps), are synonyms of the nominate tribe included I am grateful to Horst Wegner (Hannover, (in this particular example, synonyms of Me- Germany) for allowing me to examine spec- gachilini, like Coelioxynae), since such syn- imens from his collections. To each of these onyms are probably not equivalent with the collectors I am greatly indebted, particularly group at a higher rank (e.g., in this work the for their willingness to donate name-bearing family-group name based on Coelioxys types to museums (and therefore listed as be- should not be listed as synonymous with Me- longing to particular museums herein). gachilinae, since the former is not equivalent to a group inclusive of Anthidiini or other SPECIMEN PREPARATION AND STUDY tribes of the subfamily but only with the Me- gachilini). The taxonomic history is present- When possible, specimens were vacuum- ed only at its lowest rank within the family- embedded in epoxy following the procedure group so as to avoid extensive repetition of Nascimbene and Silverstein (2000). Wa- (e.g., the taxonomic history of the family- ter-fed trimming and polishing was then un- group name based on Halictus is presented dertaken on most specimens so as to make under tribe Halictini and not also under Hal- clear ``windows'' for the observation of par- ictinae and Halictidae). For extant bees com- ticular structures and photography. Amber plete details on family-group names and their pieces were then examined using a Zeiss Ste- synonyms are presented by Michener (1986) reomicroscope SV-8 and measurements made with additions and corrections by Michener using an ocular micrometer. Scanning elec- (1997) and Engel (1999e). A catalog of fam- tron microscopy was done on uncoated spec- ily- and genus-group names for fossil bees is imens using a Hitachi S4700 Field Emission presented in appendix 3, while a separate Scanning Electron Microscope for partial in- species catalog is in preparation (Engel, in clusions of Boreallodape striebichi pre- prep.). served at the amber surface (see below). I I have used the term nomen translatum for prepared a photographic slide of each spec- family-group names that have been changed imen [a few of which are presented here as in hierarchical rank (e.g., tribe elevated to either color plates or black-and-white images subfamily) and required an alteration of suf- (e.g., the frontispiece)], thereby creating a ®x. The term status novus is reserved for photographic library of bees in Baltic amber. changes in rank whereby the name retains its suf®x from the former rank without alter- FORMAT ation (e.g., subspecies elevated to species, In preparing this work the recently intro- subgenus elevated to genus). As stipulated by duced fourth edition of the International the Principle of Coordination (ICZN, 1999b: Code of Zoological Nomenclature has been Art. 36), names altered in either manner re- followed (ICZN, 1999b). Standard formats tain their original authorship and date re- are used for taxonomic histories. References gardless of rank. in each line refer only to taxonomic works In the Material sections I have presented and thus if a species was simply cited or list- detailed label information from each speci- ed by an author such a reference is excluded. men as well as a summary of the total num- 2001 ENGEL: BALTIC AMBER BEES 19 ber of specimens (immediately following the future study (satisfying ICZN, 1999b: Art. heading Material for each species). In these 75.3.7). The more dif®cult criterion to meet summaries a double slash (//) separates text is Article 75.3.4, which requires reasons for from individual labels. The material sections ``. . . believing the name-bearing type spec- are broken into paragraphs, with each para- imen(s). . . to be lost or destroyed, and the graph representing a single amber piece ex- steps that had been taken to trace it or them''. cept when the holotype and paratypes occur All of the species for which neotypes were in the same piece; otherwise multiple indi- required were originally located in the Al- viduals in a single amber block are treated bertus UniversitaÈt in KoÈnigsberg. During within the same paragraph. Each paragraph World War II the collections of this univer- is headed by a boldface indication as to sity were destroyed by ®re. I contacted nu- whether this material is a type or not. When merous institutions in search of described or two or more taxa are synonymized there are undescribed material. The bulk of KoÈnigs- two paragraphs with the boldface heading berg's surviving material found its way into ``holotype'', ``lectotype'', or ``neotype'', but the collection of the Institut und Museum fuÈr each is followed in parentheses by an indi- Geologie und PalaÈontologie, GoÈttingen. I cation as to which synonymous name it be- personally visited this institution during the longs. When the holotype for one species is summer of 1999 (as well as several other Eu- the same specimen designated as the neotype ropean collections) and inspected the entire for another, these begin separate paragraphs amber collection. From this material I was but are cross-referenced to avoid repeating only able to locate three original specimens label data. (with Cockerell's own handwritten labels). I As a result of attempting to forge a new was therefore left with the conclusion that path, I have had to make dif®cult decisions the remaining taxa, which could also not be regarding previously described taxa for traced in any other museum, must have been which specimens have since become lost or lost or destroyed during the tumultuous years destroyed, mostly through the ravages of of the last world war. For these reasons I be- world war. I therefore found it necessary to lieve to have adequately satis®ed all of the designate neotypes and in so doing to care- ICZN (1999b) requirements, inclusive of Ar- fully attempt to associate newer material with ticle 75.3.4, for the designation of neotypes. often inadequate and incomplete original de- Metrics are provided in the descriptions scriptions. This has been done expressly for for the name-bearing type specimen. All the purpose of stabilizing the nomenclature measurements should be considered approx- of fossil bees (in accordance with ICZN, imate, since it was not always possible to 1999b: Art. 75.3.1) and thereby allowing and achieve the optimal angle for making a given encouraging meaningful comparison of these measure. In the description of higher-rank taxa with Recent bees. For all of the taxa groups, italicized characters indicate features below I have provided necessary information that could not be con®rmed for the fossils for both the recognition of the specimens described within that particular group. The chosen as neotypes, my reasons for believing following descriptive abbreviations are used: them to be conspeci®c with the original ma- F, ¯agellomere; OD, ocellar diameter (always terial, and diagnoses of all of these species based on the diameter of the median ocellus); (meeting the requirements of ICZN, 1999b: S, metasomal sternum; T, metasomal tergum. Art. 75.3.2, 75.3.3, and 75.3.5). Article Descriptions are of females (of the worker 75.3.6 (ICZN, 1999b) states that the neotype caste where applicable in the corbiculate Ap- must come ``. . . as nearly as practicable inae) except for Ctenoplectrella viridiceps from the original type locality.''; since all of where a description of the male is included; the original fossils, as well as my own, orig- otherwise males are unknown. inate from middle Eocene strata of the Baltic region, I believe this criterion to have been GENERAL MORPHOLOGY suf®ciently met. All neotypes are either in the AMNH, ZMHB, GPUH, or BMNH as Numerous accounts discuss the general ex- indicated below, making them accessible for ternal morphology of bees (e.g., Michener, 20 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

1944, 1965, 2000a; Snodgrass, 1956; Ca- area (®g. 1) and is slightly set below the margo et al., 1967; Urban, 1967; Eickwort, plane of the basal area when viewed in pro- 1969; Pesenko, 1983; Engel, 2000a) and the ®le; the basal area is the portion that articu- ensuing section is not meant to entirely sup- lates with the head capsule. When the distal plant those. Instead, I have attempted to sum- process is present it is variously modi®ed marize standard terms for the external mor- with either lateral teeth or serrations, a dorsal phology of bees, to relate each characteristic ridge or keel, or tubercles of differing mor- to gross variations found among the Baltic phologies. Similarly, the basal area can bear amber fauna, and to provide new terms for tubercles and/or ridges, and is found in a va- features not previously considered. This sec- riety of gross morphological shapes, none of tion is also intended to provide a working which depend on the presence or absence of terminology for researchers and amateurs the distal process. The labrum broadly artic- collecting, organizing, and studying Baltic ulates at the apical margin of the clypeus amber inclusions. It is hoped that this over- (®gs. 1, 3), the lowermost, immovable scler- view of bee morphology will make the sub- ite of the head capsule. The basal attachment sequent systematic section and its included of the clypeus to the remainder of the head descriptions and dichotomous keys more is delimited by the epistomal sulcus (®g. 1) useful. (sometimes called the epistomal suture), Morphological terminology generally fol- which laterally forms an angle of various de- lows that proposed by Michener (1944, grees of arc; typically the angle is measured 2000a) with additions for mandibular struc- between the two portions of the sulcus open- ture by Michener and Fraser (1978), coxal ing toward the compound eye. Similarly the structure by Michener (1981a), and glossal dorsalmost, transverse portion of the episto- morphology by Michener and Brooks (1984). mal sulcus ranges from convex (i.e., bending From these accounts, however, I differ in upward and extending the clypeus dorsally), some terminologies for wing veins, mouth- straight, to concave (i.e., bending downward part structures, and leg structures most no- and shortening the clypeus). Almost univer- tably in terms used for types of pollen-car- sally (except in some living genera, such as rying apparati (see speci®c instances below). Nomioides), the anterior tentorial pits are set The following sections provide greater detail into the epistomal sulcus, frequently along its into the precise morphology of bees in gen- lateral parts. Extending dorsally from the ep- eral and the Baltic amber bees in particular, istomal sulcus to the antennal sockets are the de®ning terms frequently used throughout subantennal sutures (®g. 1). Typically there the text. is a single subantennal suture reaching each antennal socket, although in some groups PROSOMA (e.g., Andrenidae) there are two subantennal sutures reaching each antennal socket and The head, or prosoma, is the ®rst body de®ning between them a small subantennal tagma and is hypognathous. The compound area. Frequently, the subantennal suture eyes (®gs. 1, 4) are situated laterally on the meets the antennal socket along its lower head and are composed of numerous minute margin, although in the Lithurginae and Me- facets representing the individual lenses of gachilinae the single subantennal suture runs the ommatidia. At the top of the face, ar- to the outer, lateral margin (i.e., that side ranged in the pattern of an inverted triangle, nearest the compound eye) of the antennal are three simple eyes termed ocelli (®g. 1). socket. The antennal sockets (or alveoli) (®g. At the extreme lower apex of the head is the 1) are the points at which the antennae artic- labrum (®gs. 1, 3), a freely movable sclerite ulate and, together with the subantennal su- that at its base broadly articulates with the tures, serve to demarcate a poorly de®ned re- remainder of the prosoma. The labrum is gion of the head referred to as the supracly- sometimes composed of two sections: the peal area (®gs. 1, 3). The face above the distal process and the basal area. The distal level of the antennal sockets to the level of process (®g. 1) is a medioapical extension the ocelli and between is the frons (®g. 1). that extends apicad from the transverse basal The ill-de®ned region of the face running 2001 ENGEL: BALTIC AMBER BEES 21

Fig. 1. Diagrammatic representation of a bee's head (ϭ prosoma) with major morphological structures labeled. Left image is a frontal view of the head with the antennae and mandibles removed; right image is a ventral view of the head. along the inner margin of the compound eye ciput bears a large opening, the foramen and outside of the frons is the paraocular magnum, where the prosoma and mesosoma area, which is sometimes equipped with a connect. To the sides of the vertex the lateral carina running dorsoventrally along the com- portion of the head behind the eyes and ocelli pound eye (i.e., the paraocular carina: ®g. and anterior to the preoccipital ridge is the 1). In some bee lineages (e.g., Andrenidae) gena (®g. 3), which ventrally gives way to the paraocular area near the upper, inner mar- the postgena (®g. 1) on the ventral surface gin of the compound eye bears a shallow in- of the head. The postgena borders a longi- tegumental impression or facial fovea (®g. tudinal concavity composed of the hyposto- 1), sometimes covered with dense, micro- ma on the undersurface of the head and is scopic setae. At the lower extremity of the referred to as either the hypostomal fossa or compound eye is the malar area (®g. 1), a the proboscidial fossa, since the proboscis small region of integument separating the (i.e., the labium and maxilla) rests within this lower border of the compound eye from the region when in repose. The ridge separating mandibular articulation (see below). In some the hypostoma from the postgena is the hy- bee taxa there is an interocellar furrow postomal ridge (®g. 1) and, like the preoc- formed of an impressed line running between cipital ridge, can be rounded, carinate, or and just posterior to the lateral ocelli (Engel, even lamellate and frequently projects slight- 1998b, 2000a). On the top of the head and ly beyond the occiput posteriorly. Anteriorly immediately behind the ocelli is the vertex the hypostomal ridge curves laterally (®g. 1) (®gs. 1, 4), which runs to the posterior mar- and runs behind the mandibular articulation. gin of the head where the head once again Articulating with the head are a number of angles or curves ventrally to its posterior sur- appendages representing ancestral remnants face, or occiput (®g. 1). The ridge separating of a once segmented, limbed tagma of a de- the vertex from the occiput is the preoccip- bated total number of somites. The append- ital ridge (®g. 3) and surrounds the concave, ages discussed here are not presented in or- posterior surface of the head (i.e., the occi- der from anterior to posterior of their pre- put), which itself ®nally gives rise centrally sumed relative position on ancestral seg- to the postocciput that is surrounded by dis- ments. At the lower, apicolateral extremity of tinct postoccipital sulcus (or suture). The the head are the mandibles (®gs. 1, 3). The preoccipital ridge can be either rounded, an- mandibles of bees are variably structured and gled, carinate, or even lamellate. The postoc- typically sexually dimorphic. Numerous an- 22 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 atomical details concerning mandibular paired maxillae and the central labium. The structure were covered by Michener and Fra- bases of the maxillae are the site of attach- ser (1978) and it is not necessary to repeat ment and articulation of the labiomaxillary that material here. Instead, I shall focus on complex to the head capsule. The basalmost only those gross structural features that have segment of the maxilla is the cardo (®g. 2), been observed in the fossils discussed herein an elongate sclerite that attaches to the head and require some explanation of their asso- capsule. At the apex of the cardo is the stipes ciated terms. The mandibles, as in all pter- (®g. 2), the next prepalpal segment of the ygote and some apterygote insects, are di- maxilla, as well as the submentum (or lo- condylic, having two points of articulation rum), the basalmost sclerite of the labium and therefore moving in a single plane. The (see below). The ventral (lateral surface in articulation is formed of an anterior mandib- ®g. 2) margins of the stipes is sometimes ular acetabulum and a posterior condyle each concave with a distinct comb of stiff setae corresponding to an anterior condyle and set within the concavity and termed the stip- posterior acetablum on the head capsule, re- ital comb (e.g., present in many Apidae). At spectively. The apical margin of the mandi- the apex of the stipes is the frequently six- ble is frequently beset with a series of inci- segmented maxillary palpus (®g. 2). Two sions de®ning apical teeth. Along the upper sclerites form the postpalpal portion of the margin the subapical tooth (®gs. 1, 3) and a maxilla and are the elongate galea and the groove (termed the acetabular groove) run- small lacinia (®g. 2). Like the stipes, the ga- ning from the mandibular acetabulum de- lea is frequently beset (in the short-tongued marcate a region referred to as the mandib- bee families) with a comb of stiff setae on ular pollex, while the remaining area of the its inner surface, which when present is re- mandible is the rutellum. The mandibular ferred to as the galeal comb. As mentioned pollex is in some groups (e.g., the corbiculate above the basalmost sclerite of the labium is Apinae) greatly expanded to form a single, the submentum (®g. 2), which is often termed elongate cutting margin, or is divided into the lorum to indicate its dubious homology additional teeth. On the outer margin of the (Snodgrass, 1935) with the true submentum rutellum are a series of ridges that delimit an of other insects. As discussed elsewhere (En- associated number of interspaces. Along the gel, 1999b), I prefer the term submentum as lower margin of the mandile runs the con- employed by Michener (1944) in place of lo- dylar ridge (below it is the condylar groove) rum. The submentum is shaped like an in- and between this ridge and the acetabular verted ``V'' in many bees (except in groups groove is the outer surface of the mandible such as some Colletidae it is more of a broad with its outer grooves, the number and pres- inverted triangle, or in Halictidae, rectangu- ence of which can vary among bee lineages lar or membranous) with the apices of the (e.g., completely absent in some corbiculate submental arms meeting the cardines of the Apinae, such as the honey bees). maxillae. Along the inner, subapical surface The appendages of the next two head seg- of the submental arm is sometimes a small ments are intimately tied together and form spine referred to as the submental spine (®g. the primary mouthparts of the bee. Frequent- 2), most notably found in the corbiculate Ap- ly referred to as the proboscis or the labio- inae. Medially the submentum attaches to the maxillary complex, these structures represent mentum, a structure, sometimes absent or the maxillae, from the segment immediately membranous, that at its opposite end meets behind that of the mandibles, and the labium, the base of the prementum, an elongate scler- from immediately behind the maxillary seg- ite (®g. 2). The apex of the prementum is ment, united basally by membranous connec- trilobed with the lateral processes supporting tions which are typically strengthened ante- the frequently four-segmented labial palpi riorly by thin, sclerotic conjuctival thicken- and a more broad, medioapical (or subligu- ings. The overall structure of the labiomax- lar) process that varies in length (being ei- illary complex as viewed from the front of a ther shorter or longer than the lateral pro- bee where the proboscis is fully extended cesses) (®g. 2). Postpalpally on the labium (e.g., ®g. 2) can be thought of as the lateral, are the lateral paraglossae and the medial 2001 ENGEL: BALTIC AMBER BEES 23 glossa (®g. 2). As is discussed brie¯y below and metathoracic segments bear the wing ar- (under Systematic Paleontology) the mouth- ticulations and are sometimes together re- parts of bees can be grossly classi®ed into ferred to as the pterothorax. The major seg- two structural categories: short-tongued and mental structures are pre®xed by ``pro'', long-tongued. Most notably, in short-tongued ``meso'', or ``meta'' as a reference to which bees the ®rst two segments of the labial pal- thoracic segment they relate (e.g., mesocoxa, pus are cylindrical and usually more or less metatibial spurs). equal in length to the distal two segments, The pronotum, or dorsal surface of the ®rst while in long-tongued bees the basal two thoracic segment is expanded laterally to segments are greatly elongate and ¯attened. form lateral surfaces and processes (the po- In short-tongued bees the glossa is frequently stcoxal processes) that extend along the sides short (and, in the Colletidae, broadened or and behind the procoxae to form a complete usually bilobed at its apex as in the spheci- or nearly complete ring tightly adjoining the form wasps), while it is pointed and almost anterior margin of the mesothorax (®gs. 3, universally elongate in the long-tongued 4). Dorsally the pronotum extends somewhat bees. The premental fragmentum is a de- laterally and is posteriorly broadly U-shaped; tached basal portion of the prementum. This the shape of the dorsolateral angle (®g. 4), structure is involved in the articulation of the where the pronotum bends posteriorly, is a prementum with the mentum in melittid and useful taxonomic character. Along the pos- other bees. In long-tongued bees the apex of terior border of the pronotal lateral surface the glossa bears a minute additional structure and extending toward and just below the lev- termed the ¯abellum (®g. 2). Numerous other el of the mesothoracic wing base is a distinct characters of the labiomaxillary complex pronotal lobe (®g. 3) that covers the ®rst tho- could be discussed at some length, but since racic spiracle. The presence of this lobe is a they are hidden in most bee fossils, I will not synapomorphic trait of the superfamily Apo- treat them further here (but see Michener, idea. As a result of this overall pronotal mor- 1944, 2000a; Snodgrass, 1956; Eickwort, phology the propleura face ventrally and lie 1969). anterior to the procoxae (®g. 3). The pros- Lastly, the antennae are somewhat genic- ternum is mostly obscured from view be- ulate, bending at the pedicel, and, as men- tween the propleura but can be viewed inter- tioned above, articulate with the face above nally. The anterior, triangle-shaped apex of the level of the clypeus (®gs. 3, 4). The an- the prosternum has been termed by Snod- tennae are composed of three units: a basal- grass (1956) the basisternum, while the most scape that articulates via a basal bulb broad, posteriorly-projecting portion is the with the antennal socket; a short, intermedi- furcasternum. The overall shape of the pros- ary pedicel; and the typically ®liform ¯agel- ternum varies among higher bee lineages lum (rarely serrate in some odd, living gen- (e.g., tribes). The lateral processes and apical era), which is itself divided into a series of extension of the basisternum are of varying individual, cylindrical ¯agellomeres (®gs. 3, lengths and the furcasternum is similarly var- 4), sometimes called ¯agellar segments. In iable, sometimes with a more or less devel- bees the number of ¯agellomeres is dimor- oped longitudinal, medial groove. Most no- phic: females almost always having 10 and table is the variation in construction exhib- males 11. The relative lengths of the basal ited among the corbiculate Apinae (e.g., ¯agellomeres can be useful characters for Prentice, 1991) where, in the Apini and Me- separating groups of bees. liponini, there is a strong constriction immediately posterior to the basisternum (i.e., MESOSOMA between the basisternum and furcasternum). The mesonotum, or dorsal surface of the The mesosoma is a combination of the true mesothoracic segment, is divided into two thoracic tagma with the ®rst abdominal seg- primary units: the mesoscutum (or scutum) ment (ϭ propodeum). It is thus composed of and the mesoscutellum (or scutellum). The four primary segments: prothorax, mesotho- mesoscutum is the larger, anterior sclerite the rax, metathorax, and propodeum. The meso- mesonotum (®gs. 3, 4). It is laterally bor- 24 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 2. Diagrammatic representation of a long-tongued bee's labiomaxillary complex with major structures labeled. dered by small movable sclerites termed te- cutum. The notauli are short, submedial lines gulae that cover the mesothoracic wing bases that run from the anterior border to about (®gs. 3, 4). Borne upon the mesoscutum are one-third of the mesoscutal length in their a series of longitudinal, impressed lines. The most extreme case (®g. 4). The parapsidal median line (®g. 4), as the name implies, lines are also parallel to the median line, al- runs medially from the anterior border fre- though closer to the lateral, mesoscutal bor- quently to about the midpoint of the mesos- ders (®g. 4). Posterior to the mesoscutum is 2001 ENGEL: BALTIC AMBER BEES 25 Fig. 3. Diagrammatic representation of a left lateral view of a bee with major morphological features labeled. NOTE: The ®gure combines characters not found in combination in any known bee (living or fossil); graduli not illustrated for all terga or sterna. 26 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 the scutellum, the second sclerite of the me- ject over its surface to varying degrees. Lat- sonotum (®gs. 3, 4). The scutellum is fre- erally the metepisternum (®g. 3) runs from quently dorsally gently convex, while later- the metathoracic wing base (®g. 4) to the ally it is concave and forms regions referred metacoxa and typically narrows ventrally. As to as axillae (®gs. 3, 4). The axillae are im- mentioned previously, the hindmost portion mediately posterior to the mesothoracic wing of the mesosoma is the propodeum (®gs. 3, bases. The mesepisternum (®gs. 3, 4) is the 4), which is ancestrally the ®rst segment of large, lateral portion of the mesothoracic seg- the abdomen. The propodeum is frequently ment. A series of ridges and grooves run angled basally to form a dorsal-facing basal across this surface and these structures are area and a posterior surface (®gs. 3, 4). Typ- important characters for the recognition of ically, the sculpturing of the integument on suprageneric groups within bees. Running the basal area of the propodeum is diagnostic from just below the mesothoracic wing base for species or groups of species. Similarly, toward the ventral margin is the preeÈpister- the angle between the basal area and the pos- nal groove, which serves to de®ne the posterior surface can be useful for the de®nition terior border of a region termed the preeÈpis- of generic groups among bees. The propo- ternal area or preeÈpisternum (®g. 3). If the deal triangle (ϭ metapostnotum of Brothers, mesepisternum is strongly bent, then the 1976) is a distinctive region of integument preepisternal area sometimes includes an an- including the basal area or most of it and terior-facing surface. The preepisternal extending posteroventrally toward the pro- groove does not de®ne the ridge separating podeal pit (®g. 4) on the posterior surface. this anterior-facing surface from the lateral The mesosomal appendages are all born surface of the mesepisternum; this ridge is on the true thorax. The legs are composed of termed the omaular ridge and can be round- the typical series of segments (from base to ed, carinate, lamellate, or rarely entirely ab- apex): coxa, trochanter, femur, tibia, tarsus, sent. Running between the preepisternal and pretarsus; the tarsus is further subdivid- groove and the posterior border of the me- ed into the basitarsus (basalmost subsegment sepisternum is a short, longitudinal, im- or tarsomere), mediotarsus (subsegments two pressed line that crosses a pit at about its through four), and distitarsus (distalmost midpoint. This pit is termed the scrobe or subsegment) (®g. 3). The procoxae, like the episternal scrobe, while the impressed line is propleura, are situated next to one another on termed the scrobal groove (®g. 3). Above the the anteroventral surface of the mesosoma. scrobal groove is a usually convex region of The meso- and metacoxae are typically more frequently distinctive sculpturing referred to well separated from one another, situated on as the hypoepimeral area (®g. 3). The sub- the ventral surface of the posterior half of the pleural signum is a small, impunctate, fre- mesosoma and closer to one another than ei- quently raised spot at the separation of the ther is to the procoxae. In most short-tongued pleural and ventral portions of the mespis- bees families (i.e., Colletidae, Halictidae, ternum. The precoxal triangle is a distinctive Andrenidae) the mesocoxa is hemicryptic, area of sculpturing on the mesepisternum that is to say its dorsal articulation is partially bordering the mesocoxa in glyptapine bees hidden inside of the mesosoma. All other bee (®g. 3). The precoxal triangle is delimited by families (i.e., Paleomelittidae, Melittidae, a carina on all sides (posteriorly this carina Megachilidae, and Apidae) have a fully ex- is the precoxal carina). The integumental posed mesocoxa. The metacoxa is fully ex- sculpturing within the precoxal triangle or posed and ventral to the metepisternum and the structure of its separation from the re- anterior portion of the propodeum. The pro- mainder of the mesepisternum is quite useful trochanters are slightly laterally compressed for separating species of the genus Glyptapis. segments that articulate in a longitudinal The metathoracic segment is greatly short- plane (rather than vertical plane of move- ened longitudinally by comparison to the me- ment as in the meso- and metatrochanters). sothorax. Dorsally it is represented by the The femora and tibiae are elongate, tubular metanotum (®gs. 3, 4) immediately posterior segments, typically widest at their midpoint. to the scutellum, which may sometimes pro- On the ventral, mediobasal surface of the 2001 ENGEL: BALTIC AMBER BEES 27

Fig. 4. Diagrammatic representation of a bee's prosomal and mesosomal dorsum with major anatomical structures labeled. mesofemora is a dense, longitudinal series of queen caste of some eusocial species. The leg short setae that form the mesofemoral comb. segments bearing the scopal setae are useful Similarly, on the inner, medioapical surface characters for the separation of higher line- of the mesotibia is a dense, longitudinal se- ages among bees (e.g., in the extreme case ries of setae termed the mesotibial comb. The the complete absence of scopal setae on the metathoracic legs are typically modi®ed for legs helps to characterize numerous parasitic the transport of pollen (although this is by no taxa as well as groups such as the megach- means universal for bees; e.g., in Megachil- ilids, where the scopal setae are born on the idae pollen is carried on the metasoma). The metasomal sterna). Thus, among bees there scopa is developed to varying degrees and are metasomal scopae, femoral scopae, tibial consists of elongate, frequently plumose se- scopae, &c. Perhaps the most distinctive pol- tae on a variety of metathoracic leg segments len-carrying apparatus is the corbicula or of females except in parasitic species and the ``pollen basket'' (®g. 5). The corbicula is 28 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 formed by an expansion of the metatibia to- into part of an antenna cleaner or strigilis ward its apex; it is somewhat ¯attened and (®g. 3). The thickened, spur ``backbone'' of the outer surface concave to varying degrees. the strigilis is the malus, while along its inner The concave region on the outer surface basal margin is a broad lamella termed the (varying in length, although typically com- velum (®g. 3). The overall shape of the ve- prising only the apical half of the metatibia) lum does not vary greatly (typically it is is bordered anteriorly and posteriorly by roughly rectangular, but sometimes the outer elongate scopal setae. Michener (1999) has, margin of the lamella is slightly concave), as have some other authors (e.g., Thorp, although some corbiculate Apinae (e.g., 1979), used the term corbicula more inclu- Bombini, Electrobombini) there is a second sively for any glabrous, frequently concave anterior velum formed from a thickening surface bordered by fringes of elongate sco- along the anterior border of the malus and pal setae and used for the transport of pollen. approximately orthogonal to the true velum; Thus some structures found in other bee the anterior velum is not always developed groups (e.g., andrenines, halictines) may into a lamella like the true velum. The distal have what these authors refer to as ``femoral portion of the malus that extends beyond the corbiculae'' or ``propodeal corbiculae''. In velum is either serrate, ciliate, or pectinate attempting to denote the uniqueness of the with a series of long teeth gradually decreas- actual structure found only in the corbiculate ing in size apically. The mesotibial spur, Apinae, i.e., those taxa not only exhibiting while varying to some degree in length, is the corbicula as de®ned by Michener (1999) almost universally serrate or minutely ciliate. but also the associated modi®cations of the Among some living bee lineages there are metatibia, I prefer to restrict the term corbic- other minor modi®cations of its apex, e.g., ula to this structure. Those other pollen-car- within Ericrocidini. The presence/absence or rying apparati termed corbiculae by Miche- shape of the metatibial spurs varies dramat- ner (op. cit.), are here referred to as either ically among bee groups. In some lineages corbiculate scopae or more appropriately as (e.g., the Meliponini and Apini) the spurs are ®scinae (sing. ®scina: L. meaning ``¯ower or entirely absent, while in several other groups bread basket''). Thus corbiculae s.s. are ho- a single metatibial spur is present (e.g., Elec- mologous structures found in a single clade trapini, Melikertini). The spurs are typically of apine bees. Both scopae and ®scinae are of one of the three morphologies: serrate, cil- more general terms for other pollen-carrying iate, or pectinate; when two metatibial spurs structures and are not necessarily homolo- are present the inner and outer spurs are not gous across taxa. Thus, it may prove at a necessarily of the same morphological type. later time to be useful to indicate such ho- Along the inner, apical margin of the meta- mologies by their own terms owing to the tibia of corbiculate apines is a tight series of diversity of ®scinae among bees (e.g., the short, stiff setae known as the rastellum (®g. term ``canistra'' for a ``propodeal fascina''). 5). In the Meliponini the outer surface of the The inner surface of the metatibia of many corbicula near the posteroapical corner there bees and wasps is covered by a dense ®eld is a penicillum (®g. 5), or dense patch of of minute, blunt setae termed keirotrichiae. modi®ed setae. As mentioned above, the tarsi The region occupied by the keirotrichiae is are composed of ®ve subsegments, the ®rst termed the keirotrichiate ®eld (®g. 5) and its of which is always greatly elongate by com- separation from the remainder of the meta- parison to the distal four, and is referred to tibial inner surface is a useful systematic as the basitarsus. On the inner, basal surface character among Meliponini and Electrapini. of the probasitarsus is a deep concavity cor- Articulated on the inner apex of the tibiae are responding in relative position to the velum spurs, the number and general structure of of the strigilis and serves as part of the an- which vary on legs of differing segments; tenna cleaning apparatus. This concavity is there is a single protibial spur and a single the strigilar concavity (®g. 3) and is fre- mesotibial spur, while the inner apex of the quently equipped with a linear series of ®ne metatibia ordinarily has two metatibial spurs setae to form a strigilar comb. The probasi- (®gs. 3, 5). The protibial spur is modi®ed tarsus sometimes also bears a tight, longitu- 2001 ENGEL: BALTIC AMBER BEES 29 dinal series of setae referred to as a probas- metathoracic segments and are joined to the itarsal comb; non-homologous combs occur mesosoma via a series of complex, minute in a variety of positions and serve differing axillary sclerites. For further details on the functions (e.g., Augochlorini, Tapinotaspidi- morphology of the axillary sclerites in bees ni). The mesobasitarsus is little different refer to Michener (1944) and Snodgrass from the probasitarsus except that it lacks the (1956). The wings are formed of a membrane stigilar concavity. The metabasitarsus is braced by longitudinal, sclerotic veins (ab- broader than the metamediotarsus and meta- breviated by capital letters) that are them- distitarsus, although the degree of its length- selves, when not fused, connected at various to-breadth ratio ranges dramatically across points by transverse crossveins (abbreviated bee lineages. In some tribes of the corbicu- by lowercase letters). At the wing base the late Apinae (i.e., Euglossini, Bombini, Elec- longitudinal veins in the forewing are (from trobombini, Electrapini, Melikertini, Apini) anterior to posterior: ®g. 6) the costa (C), the the base of the metabasitarsus is modi®ed fused subcosta and radius (ScϩR), the media into an auricle or pollen press (®g. 5). The fused with the cubitus (MϩCu), and the ®rst auricle is formed of a slightly concave sur- anal (A); the radius further out in the wing face bordered by a carina or lip that is par- splits to form a posterior branch termed the ticularly broadly developed along the outer radial sector (Rs). At roughly one-third of margin. The microsculpturing of this concav- the total forewing length from the base, the ity is typically equipped with rows of micro- media and cubitus separate and follow sep- scopic, broadly ¯attened, pointed spicules di- arate courses, the former eventually fuses for rected toward the outer margin. The auricle, a short distance with the radial sector before which is used to compress and move pollen separating once again shortly thereafter (®g. into the corbicula for transport, is sometimes 6); the ®rst abscissa of M (the free portion bordered along its outer margin by a series of this vein immediately after its separation of more or less stiff setae here referred to as from Cu) is termed the basal vein. In the the auricular basket. The posterior apical or hind wing the longitudinal veins are ScϩR outer apical corner of the metabasitarsus is (the costa is lost in the hind wing, leaving an sometimes extended apically into a distal unbraced, membranous leading edge), process beyond the articulation of the meta- MϩCu, and A. Along the leading edge of the basitarsus to the metamediotarsus. This distal forewing there is an enlarged, sclerotized re- process sometimes bears a penicillus (not to gion (that weighs the leading edge of the be confused with the penicillum on the me- wing) termed the pterostigma and formed of tatibia of Meliponini) or brush of dense, an expansion in R. Immediately basal to the modi®ed setae. The distatarsus is frequently pterostigma is a region formed of an expan- slightly more elongate than the subsegments sion of ScϩR termed the prestigma. The bas- of the mediotarsus. The pretarsi bear the almost edge of the prestigma is de®ned by paired claws, which themselves sometimes the point at which the ®rst abscissa of Rs bear an inner notch of varying depths to form originates from ScϩR. The leading edge of an inner tooth (®g. 3). Toothed claws occur the hind wing is equipped with a series of in most bees, although some lineages (e.g., minute hooks termed hamuli (®g. 7), which Megachilini) have simple claws. Between the link the two sets of wings in ¯ight. The num- claws is a membranous lobe or arolium (®g. ber and pattern of arrangement of the hamuli 3), the presence or absence of which is an is variable across bee taxa and is a useful important character for distinguishing taxa in taxonomic character. Crossveins are denoted a variety of lineages. A number of other as- by two letters indicating which longitudinal sociated structures are present in the protar- veins they connect; anterior vein ®rst, pos- sus [these are covered in greater depth by terior second (i.e., rs-m runs between Rs and Michener (1944)]; none of these structures M). Sections of the longitudinal veins run- were observed for the Baltic amber bees ning between two crossveins are termed ab- (owing to their minute size and optical lim- scissae and are numbered from base to apex; itations). similarly, when more than one crossvein oc- The wings are borne on the meso- and cur between a pair of longitudinal veins they 30 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 5. Diagrammatic, corbiculate metatibiae with structures labeled. Left metatibia depicts an outer surface; right metatibia depicts an inner surface. NOTE: The ®gured metatibiae are not meant to represent outer and inner surfaces of the same leg or a single species. are numbered consecutively from base to the order so as to indicate the homologies of apex and this number precedes the crossvein these veins not only among superfamilies of abbreviation (e.g., 2m-cu). At speci®c loca- Hymenoptera but, as best as can be done, tions certain veins are crossed by minute across insect orders. A few of these differ- clearings of sclerotization termed alar fenes- ences are as follows: 1. the anal vein is often trae that indicate ¯exion lines where the referred to as the vannal vein (abbreviated as wing will bend or fold during the motion of ``V'') in other works on bees; 2. those veins ¯ight. Some of these lines are indicated in delimiting the apical edge of each submar- wing illustrations by dotted lines crossing the ginal cell and often referred to as the trans- submarginal cells and their associated veins. verse cubitals (despite having no association Fusion and confusion would be an appropri- with the cubitus!), or more appropriately the ate descriptor for the pattern of veins in the submarginal veins (referred to as transverse Hymenoptera forewing and its changes submarginals in Michener, 2000a), are con- through the evolutionary history of the order. sidered to be herein, from basal to apical, the It would be excessive to discuss at length second abscissa of Rs, 1rs-m, and 2rs-m every point at which two veins merge, sep- (when only two submarginal cells are present arate, remerge, and eventually terminate. these veins are second abscissa of Rs and Thus, for the sake of brevity, I refrain from 2rs-m; see below), respectively; in other ac- such a discussion here and refer the reader counts where the vernacular terms are not to ®gure 6 where all of the veins are labeled. employed the indication that the latter two It must be noted that some of the vein terms crossveins arise from Rs is dropped and they used here differ from other works on bees. I are termed 1r-m and 2r-m; 3. in a similar have attempted to standardize the wing vein fashion the small crossvein running between terms of the Apoidea with general work on the pterostigma (R) and the posterior border 2001 ENGEL: BALTIC AMBER BEES 31 of the marginal cell (formed of Rs) just be- the wing. These incisions and furrows de- yond the ®rst submarginal cell is actually the marcate speci®c regions of the insect wing r-rs crossvein but is frequently and enigmat- that appear as lobes along the posterior edge ically referred to as simply ``r'', presumably of the wings. The basalmost lobe is the jugal owing to the fact that this crossvein runs be- lobe (®g. 7), which de®nes the anterior bor- tween two portions of the radial system; 4. der of that region of the wing termed the ju- in the hind wing the crossvein r-m is changed gum. The absence, presence, and size of the to rs-m to regain, once again, more infor- jugal lobe in the hind wing is a useful char- mation pertaining to which section of the ra- acter for recognizing groups of bees. This dial system this vein connects to the medial structure, however, can be easily misinter- system. Thus, although these are minor al- preted even in living bees since the jugal terations to the terminology of bee wing lobe frequently folds under the remainder of veins, they more accurately re¯ect the iden- the hind wing and therefore appears absent. tity of the veins as they are presently under- In fossil bees this is even more problematic stood and refer to homologies outside of the since the amber often makes it dif®cult to Apoidea. The membranous regions of the discern the margins of such a folded lobe wing running between the veins are termed when attempting to look through the mem- cells when bounded on all sides by veins. brane of the wing; this is further complicated The cells of the forewing and hind wing are by the fact that amber sometimes has a indicated in ®gure 7. I will mention only two ``clearing'' effect on wing veins and mem- sets of cells that play a particularly important brane, making them appear more faint. The role in the following descriptions and keys. next more apical lobe is the vannal lobe (®g. The marginal cell is the large membranous 7) and is de®ned by a fold running near to region apicad the pterostigma and bordered the anal vein; the region between the jugal by R anteriorly and r-rs and Rs posteriorly. fold and the vannal fold is the vannus. The This cell is variously modi®ed, particularly vannus is the posterior part of a region typ- at its apex, which can be set along the lead- ically termed the clavus among other groups ing edge of the wing, bent away from the of Hymenoptera and other insects; the asso- leading edge of the wing to different degrees, ciated structures are referred to in those in- become broadly truncated (e.g., Perditini, stances as the claval lobe and claval furrow some Electrapini), sometimes equipped with a minute abscissa of Rs beyond the cell (the (the latter of which typically runs just pos- cell is referred to as appendiculate when this terior to Cu). Thus, in other groups of Hy- abscissa is present: e.g., ®g. 7), or in the most menoptera what is referred to in bees as the extreme case be entirely open (e.g., the sting- vannal lobe is sometimes termed the claval less bees: ®gs. 111, 113). The submarginal lobe. The remainder of the wing membrane cells are a longitudinal series of two or, more apical from the axillary region (bearing the frequently, three cells immediately posterior axillary sclerites) is the remigium. The lobes to the pterostigma and marginal cell; when of the hind wing are particularly useful for only two cells are present it is typically ow- classifying bees. The relative sizes of the ju- ing to a loss of 1rs-m, thereby effectively gal and vannal lobes as well as the presence uniting the second and third submarginal or absence of the former are useful phylo- cells. The shapes and and relative sizes of genetic and taxonomic characters. Because the submarginal cells are useful for distin- they are rather uniform, those lobes of the guishing species and genera of bees. In one forewing are not typically referred to for of the most extreme instances (i.e., the fore- classi®catory purposes, but the vannal lobe, wing of some Meliponini) the loss of the dis- at the minimum, is present. The membrane tal wing veins has left not only the marginal of the wings is typically covered by minute cell open at its apex, but the submarginal setae, although in some bee groups (e.g., Xy- cells are completely lost (e.g., ®gs. 111, 113). locopa, Bombus, Electrobombus) the apical The posterior edge of the membrane of the portion of the wing beyond the veins is stud- wings is typically incised at speci®c sites that ded with minute, darkened swellings termed indicate the endpoints of particular folds in alar papillae (labeled as such in ®g. 6). The 32 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 6. Diagrammatic wing with longitudinal and crossveins labeled as well as a single membrane feature (i.e., alar papillae). Upper image is a forewing; lower image is a hind wing. wing membrane is usually hyaline but can be ®rst metasomal tergum is constricted anteri- infuscated or patterned to varying degrees. orly to join the mesosoma and is therefore typically composed of an anterior-facing sur- METASOMA face as well as a dorsal-facing surface. In the The metasoma consists of the true abdo- Lithurginae the ®rst tergum is shortened such men minus the ®rst segment that is fused to that there is no dorsal-facing surface. Run- the thorax. Each of the metasomal terga and ning transversely across the basal half or the sterna has a suite of morphological structures middle (or basal part of the visible portion associated with them, but are not discussed of terga and sterna) of each tergum and ster- further here since they are almost universally num at about the level of the spiracle is a unobserved for the known fossil bees. For a distinct line that is frequently carinate or mi- more complete discussion of the exoskeletal nutely lamellate, referred to as the gradulus morphology of the metasoma refer to Mich- (®g. 3). The gradulus divides the terga and ener (1944, 2000a), Snodgrass (1956), and sterna into pregradular and postgradular re- Eickwort (1969), among other authors. The gions. 2001 ENGEL: BALTIC AMBER BEES 33

Fig. 7. Diagrammatic wing with membranous cells and gross anatomical structures labeled. Upper image is a forewing; lower image is a hind wing.

The terminalia (i.e., sting apparatus, male tures, particularly those of the male, refer to genitalia) of bees is not considered in the Snodgrass (1935, 1941, 1956), Michener present work simply owing to the fact that in (1944, 1965, 2000a), or Eickwort (1969), no Baltic amber bee specimen are these among other publications. structures visibly preserved (except the sting apex in many individuals and with less fre- SYSTEMATIC PALEONTOLOGY quency the worker gonostyli). The sting is the modi®ed ovipositor of female Aculeata This section covers the descriptive mor- (®g. 3), while the female gonostyli, or sting phology and taxonomy of all bees presently sheaths, are what are typically referred to as known in Baltic amber. Numerous keys are the third valvulae (which themselves are the presented, all of which apply only to those apical accessory lobes or styli of the second groups presently known from Baltic amber. valvifer: see Snodgrass, 1935; Michener, Therefore, in each case the reader should not 1944). For information on terminal struc- be alarmed at the exclusion of certain taxa 34 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

(e.g., the absence of Colletidae from the key TABLE 4 to families of bees, for this family is not cur- Familial Classi®cation of Superfamily rently known from the middle Eocene of Eu- Apoidea rope). Likewise, characters are employed that may only apply to certain groups of a particular family if those particular groups are the only ones presently known in Baltic amber. For example, the strongly arcuate basal vein is given as a character to separate Halictidae in the key to families, because only the subfamily Halictinae is presently known in Bal- tic amber, even though the subfamilies Ro- phitinae and Nomiinae lack this feature. Sim- ilarly, within Apidae, only corbiculate apines are presently known in Baltic amber and so the key to subfamilies of Apidae uses the presence of a corbicula to separate Apinae from Xylocopinae, even though numerous living tribes of Apinae also lack a corbicula. Thus, future researchers discovering bees in Baltic amber should be careful when using these keys, since new specimens may represent higher rank groups (e.g., the aforemen- COMMENTS: The superfamily Apoidea con- tioned Colletidae) that would be new records sists of two primary divisions: the paraphy- for Baltic amber and were unknown to me at letic assemblage of spheciform wasps (fam- the time of this study. Naturally, I would be ilies Angarosphecidae, Ampulicidae, Cra- interested in examining any newly discov- bronidae, Heterogynaidae, and Sphecidae), ered fossils for the preparation of future sup- and the monophyletic bees (Apiformes). The plements to this monograph. ``Spheciformes'' is not treated further herein. Table 4 summarizes the familial classi®cation SUPERFAMILY APOIDEA LATREILLE of the superfamily. It has been observed that the name Sphe- DIAGNOSIS: Aculeate Hymenoptera mac- ciformes is a hybrid name (composed of ropterous in both sexes; sexual dimorphism Greek sphekos and Latin forma) and should slight. Antenna with 10 ¯agellomeres in fe- therefore be replaced by appropriately males and 11 in males (except in a few, apo- formed names; namely Sphecomorpha (ϭ morphic instances). Posterior border of pron- Spheciformes) and Melissomorpha (ϭ Api- otal lateral surface extended just below level formes). I have chosen to follow Brothers of wing base to form a distinct pronotal lobe; (1975) for these informal groups rather than postcoxal process of pronotum greatly pro- employ those terms of wholly Greek origin. duced mesad and approaching counterpart (processes well separated in most spheciforms, while being much closer, if not in con- Key to Divisions of Apoidea tact, in bees); posterodorsal margin of pron- 1. Body setae simple; metabasitarsus not broad- otum broadly U-shaped. Prepectus transverse er than remaining tarsal segments, fre- and fused midventrally to mesopleuroster- quently with strigil; female T7 not divided num. Metapostnotum (``propodeal triangle'') into hemitergites ...... ``Spheciformes'' expanded, fused to propodeum. Forewing ± At least some setae, particularly those of legs with well-developed venation, frequently and surrounding propodeal spiracle, with 9 to 10 closed cells; hind wing frequent- branched or plumose; metabasitarsus ¯at- ly with jugal lobe. Metasomal S1 and S2 not tened, wider than remaining tarsal seg- separated by a strong constriction. Ovipositor ments, without strigil; female T7 divided concealed at rest and modi®ed as sting. into hemitergites (bees) ..... Apiformes 2001 ENGEL: BALTIC AMBER BEES 35

DIVISION APIFORMES versal (also, one is a paraphyletic group). (THE BEES) The long-tongued bee families (Megachili- dae and Apidae) have the ®rst and second DIAGNOSIS: Some setae branched or plu- segments of the labial palpus sheath-like mose; subantennal sutures internally con- (i.e., elongate and ¯attened), while short- nected to fan-shaped sheet of tentorium; la- tongued families (Colletidae, Halictidae, An- brum thickened basally and attached at clyp- drenidae, Paleomelittidae, and Melittidae) eal margin; proboscidial fossa opened onto have these same segments cylindrical and posterior surface of head capsule; cardo not more or less similar to the following seg- broadened apically, approximately parallel- ments. The long-tongued families have been sided; suspensorium of paraglossa with repeatedly demonstrated to be a monophy- sparse setae or bristles; mesotibial comb pre- letic group; the short-tongued families are sent; dorsoventral length of mesocoxa about not. The short-tongued family Melittidae, in equal to distance from summit of mesocoxa particular, has been demonstrated to be more to hind wing base; metabasitarsus broader closely related to the Megachilidae ϩ Apidae than following tarsal segments, without con- clade owing to the shortened jugal lobe, fully cavity or strigil; cu-a of hind wing shorter exposed mesocoxa, and V-shaped submen- than second abscissa of MϩCu; T7 of female tum, among other characters. Michener and divided into two hemitergites. Greenberg (1980), for the purposes of a dis- COMMENTS: The bees are a monophyletic cussion on the higher-level phylogeny of group among the Apoidea. Although I have bees, subdivided these groups so as to re¯ect not included it in the list above, an additional the special position of Melittidae among character diagnosing the bees includes the short-tongued bees. Most notably these au- vegetarian diet of the larvae. Aside from a thors distinguished ``basic short-tongued few, apomorphic exceptions bee larvae con- bees'' apart from ``short-tongued bees'' (as sume pollen, nectar, and plant oils. well as other phenetic groupings not em- McKenna and Bell (1997: 513) presented ployed here). In the following text I regularly a series of ranks and suf®xes for family- refer to these entities for comparative pur- group names (adapted from Bour and Du- poses. It therefore seems worthwhile to brief- bois, 1984) that could be applied to provide ly provide a de®nition of these terms. more hierarchy to the classi®cation of Apo- LONG-TONGUED BEES (ϭ Megachilidae idea. In particular the rank of epifamily (in- and Apidae): families with elongate and ¯at- termediate between superfamily and family tened labial palp segments one and two; jugal and with suf®x -oidae) could be applied to lobe shortened; mesocoxa fully exposed; refer to the bees as a whole. This would re- submentum V-shaped; preeÈpisternal groove sult in what I have called division Apiformes absent at least below level of scrobe. being replaced by epifamily Apoidae. Since SHORT-TONGUED BEES (ϭ Colletidae, Hal- this name would be quite similar to the su- ictidae, Andrenidae, Paleomelittidae, and perfamilial name (i.e., Apoidea), I feel that it Melittidae): families with cylindrical labial would merely lead to confusion with the palp segments one and two. Among this more inclusive group consisting of the sphe- group the Melittidae stand out by having the ciforms and bees. I have, therefore, used in- short jugal lobe, V-shaped submentum, ab- formal names without of®cial ranks for these sence of the preepisternal groove; and fully intercalary entities. exposed mesocoxa typical of the long- tongued bees. Paleomelittidae is also note- SHORT-TONGUED VERSUS LONG-TONGUED worthy in that it has the characters of the BEES basic short-tongued bees (de®ned below) ex- Bees have been segregated into major cept this family has a fully exposed meso- groups; or the short- and long-tongued bees, coxa and lacks a preeÈpisternal suture (like a division originally recognized by Kirby Melittidae and long-tongued bees) but retains (1802) and used ever since. Although these the elongate jugal lobe. vernacular names are useful, they are a bit of BASIC SHORT-TONGUED BEES (sensu a misnomer as these characters are not uni- Michener and Greenberg, 1980: ϭ Colleti- 36 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

dae, Halictidae, and Andrenidae): families DESCRIPTION: Subantennal suture meeting with cylindrical labial palp segments one and inner, lower margin of antennal socket, infre- two; jugal lobe elongate; mesocoxa hemi- quently lower margin; two subantennal su- cryptic; submentum plate-like; preeÈpisternal tures in some Rophitinae otherwise only one groove complete. subantennal suture present (only one in the known fossils). Facial foveae typically ab- Key to Families of Bees in Baltic Amber sent. Galea elongate prepalpally. Mentum (Based on Females) and submentum absent; segments one and 1. Scopa strongly developed on metasomal ster- two of labial palpi similar to distal segments, na; subantennal sutures directed to outer cylindrical, rarely elongate; glossa acute, typ- margins of antennal sockets (®gs. 26, 32, ically short, without ¯abellum. PreeÈpisternal 40); long-tongued bees ...... groove complete (except in Nomiinae groove ...... Megachilidae Latreille weak or absent below scrobe). Mesocoxa ± Scopa not developed on metasomal sterna, with exposed area shorter than distance from variously developed on hind legs; suban- summit to metathoracic wing base; metaba- tennal sutures attaching to antennal sockets sibitial plate frequently present (except in on inner or lower margins (e.g., ®gs. 12, parasitic forms); scopa developed on hind leg 17, 21, 49, 59, 64); short- or long-tongued in nonparasitic females. Jugal lobe of hind bees ...... 2 2. PreeÈpisternal groove absent below level of wing much more than half as long as vannal scrobe; mesocoxa fully exposed; basal vein lobe. Pygidial plate present in females. Vol- variously shaped; short- or long-tongued sellae present. bees ...... 3 COMMENTS: The family presently contains ± PreeÈpisternal groove present and complete; three subfamilies: Rophitinae, Nomiinae, and mesocoxa hemicryptic; basal vein strongly Halictinae. The monophyly of the rophitines arcuate (®g. 13); basic short-tongued bees remains to be tested and the subfamily is ...... Halictidae Thomson possibly paraphyletic. The Nomioidinae sen- 3. Jugal lobe of hind wing short (e.g., ®gs. 63, su Alexander and Michener (1995) and 76); ¯abellum absent or present; preeÈpis- Michener (2000a) is considered here as the ternal groove either present or absent; short- or long-tongued bees ...... 4 basal tribe of Halictinae (see also Engel, ± Jugal lobe of hind wing elongate; ¯abellum 2000a; Pesenko, 1999; Pesenko et al., 2000). absent; preeÈpisternal groove absent below Of these subfamilies, only the Halictinae is level of scrobe; short-tongued bees .... presently known from the fossil record...... Paleomelittidae n. fam. 4. Short-tongued bees (i.e., labial palp segments Subfamily HALICTINAE Thomson one and two cylindrical and similar in length to distal segments); ¯abellum ab- DIAGNOSIS: This subfamily is most closely sent; galea not elongate or if elongate then related to the Nomiinae, both sharing the de- prepalpally, galeal comb present ...... velopment of the scopa on the metafemur ...... Melittidae Schenck ± Long-tongued bees (i.e., labial palp segments (rather than the metatibia in Rophitinae), the one and two elongate and ¯attened); ¯a- distal process of the labrum (absent in Ro- bellum present; galea elongate postpalpally, phitinae), and strong distal process with a galeal comb absent .... Apidae Latreille penicillus on the metabasitarsus (either completely absent or under-developed in the bas- SHORT-TONGUED BEES almost subfamily, Rophitinae). The halictines can be separated from the nomiines most no- Family HALICTIDAE Thomson tably by the third submarginal cell being DIAGNOSIS: The halictids comprise three shorter than the ®rst submarginal cell, by the homogeneous subfamilies of basic short- prepygidial ®mbria being typically divided tongued bees (i.e., cylindrical labial palp seg- by a longitudinal median line or area, and by ments, elongate jugal lobe, hemicryptic me- the complete and strong preepisternal socoxae, &c.; see above). Halictidae is most groove. notable for the loss of the mentum and sub- DESCRIPTION: Labrum of female with distal mentum. process. Clypeus longer than labrum. PreeÈ- 2001 ENGEL: BALTIC AMBER BEES 37 pisternal groove strongly impressed below TABLE 5 level of scrobe. Basal vein strongly arcuate; Hierarchical Suprageneric Classi®cation of ®rst submarginal cell longer than third sub- Halictidae marginal cell. Scopa developed on metacoxa, metatrochanter, metafemur, and to varying degrees on metatibia in nonparasitic females; metabasitarusus with distal process and penicillus. Prepygidial ®mbria of female distinctly divided by pseudopygidial area. COMMENTS: Traditionally this subfamily includes three tribes: Augochlorini, Halictini, and Nomioidini; however, see Engel (2000a) for an alternative classi®cation dividing the paraphyletic Halictini into at least ®ve tribes. The classi®cation of Engel (2000a) is adopted here and summarized with slight modi®- cation in table 5. The halictines are the only subfamily of Halictidae recorded from the fossil record. The tribes Caenohalictini (Eickwortapis) and Augochlorini (Augochlora, Neocorynura, and Oligochlora) are present in Miocene amber from the Dominican Republic (table 1). Numerous compression fossils of the Halic- tini are recorded from the Eocene-Oligocene boundary of Florissant, Colorado (Engel, 1996, unpubl. data), as well as some specimens in scattered, younger deposits throughout the world (e.g., Bachmayer et al., 1971; Engel, 1996; Arillo et al., 1996) but the tribal placement of these fossils is slightly uncertain (all are likely to be Halictini s.s.). Bach- DIAGNOSIS: This tribe is most similar to the ofen-Echt (1949) reported a ''Halictus'' from Gastrohalictini (ϭ Lasioglossum group) but Baltic amber, but I have been unable to lo- differs most notably by the strong distal wing cate the material from which he made his venation. determination. Oddly, Bachofen-Echt (1949) DESCRIPTION: Anterior tentorial pits set in referred his fossil ''Halictus'' to the subfam- epistomal sulcus (not in clypeus and con- ily Apinae (a gross misplacement even al- nected to epistomal sulcus by a distinct sul- lowing for the taxonomic conventions of his cus as in Nomioidini); distal wing venation time; even the most radical of classi®cations strong; pseudopygidial area of T5 in females never classi®ed Halictus with the apines!). lacking a median cleft; males with a pygidial Below I describe the only de®nitive halictine plate present on the apex of T7; males lack- in Baltic amber. ing a spiculum; ®rst and second metatarsal segments of male not fused. Tribe HALICTINI Thomson COMMENTS: I have used here the narrowed concept of Halictini as presented by Engel Sphecodidae Schenck, 1869: 316. Type genus: (2000a: 67) excluding the weakened wing Sphecodes Latreille, 1804. Suppressed in favor vein groups, the agapostemonine genera, the of Halictina Thomson (Michener, 1991; ICZN, 1993). caenohalictine genera, and the augochlorine Halictina Thomson, 1869: 8. Type genus: Halictus genera. Such a narrowing of the tribe to ex- Latreille, 1804. clude the latter groups makes the Halictini Thrinchostomini Sakagami, 1974: 258. Type ge- putatively monophyletic. Table 5 outlines the nus: Thrinchostoma Saussure, 1890. classi®cation of Halictidae adopted herein. 38 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 8. Right lateral habitus of holotype female of Electrolictus antiquus, new species. Scale bar ϭ 1 mm.

Electrolictus, new genus s.s. and Diagonozus) have a distinctive, dense setal patch near 1rs-m in the forewing TYPE SPECIES: Electrolictus antiquus En- gel, new species. which Electrolictus lacks. DESCRIPTION: Mandible with strong sub- DIAGNOSIS: This group appears in some respects to be similar to the principally African apical tooth, mandible almost bidentate (®g. genus Patellapis (sensu Michener, 1978) 11). Malar space much shorter than basal combining features of the subgenera Patel- mandibular width, base of mandible nearly lapis s.s. and Chaetalictus. From Chaetalic- touching lower margin of compound eye (®g. tus the fossil differs by the strongly bordered 10). Basal area of labrum with a low apical, metabasitibial plate that is not obsolescent suborbicular elevation; distal process nar- anteriorly, while from Patellapis s.s. the fos- rowly triangular and laterally serrate with sil differs by the absence of metasomal setal dense, long, lateral ®mbria (®g. 11); distal bands. From the whole genus Patellapis, keel of dorsal process strong without basal Electrolictus can be distinguished by the ab- expansion, slightly wider at apex. Hyposto- sence of tomentum, absence of metasomal mal ridge carinate (®g. 11), anterior angle banding, reception of both m-cu crossveins rounded, ridges parallel (not diverging ante- by the third submarginal cell, and sparse and riorly). Proboscis not greatly narrowed simple mesosomal pubescence. The recep- (length less than six times width); glossa rel- tion of both 1m-cu and 2m-cu in the third atively short; maxillary palpal segments submarginal cell is reminiscent of Thrin- about equal in length, total length of palpus chostoma but Electrolictus differs from this about 90% of prementum length. Clypeal genus by the absence of tergal setal bands truncation without short, lateral processes (in Thrinchostoma these are formed by lat- (®g. 12), lower half of clypeus below lower erally directed setae along the apical mar- tangent of compound eyes (®g. 12); clypeus gins), strong preeÈpisternal groove, and ex- gently convex, not protuberant in lateral view tremely short malar space. Furthermore, most (®g. 10). Epistomal sulcus forming a greatly Thrinchostoma (subgenera Thrinchostoma obtuse angle, nearly linear (®g. 12). Supra- 2001 ENGEL: BALTIC AMBER BEES 39 clypeal area not protuberant in lateral view. 8.17 mm; forewing length 5.60 mm. Head F1 about as long F2 (®gs. 9, 10). Gena slight- slightly longer than wide (length 2.08 mm, ly narrower than compound eye in lateral width 1.68 mm). Face relatively ¯at in lateral view. Compound eyes without pubescence; view. Upper interorbital distance 1.28 mm; inner margins slightly emarginate above lev- lower interorbital distance 1.16 mm. Vertex el of antennal sockets; eyes slightly converg- unmodi®ed, relatively short (ca. 1 OD in ing below. Ocelli not enlarged; interocellar length: measured from posterior margin of furrow absent (®g. 9). Preoccipital area lateral ocellus to preoccipital area. Interocel- rounded. Pronotal dorsal ridge carinate; lat- lar distance 0.36 mm; ocellocular distance eral ridge rounded; dorsolateral angle slightly 0.28 mm; median ocellus to lateral ocellus obtuse (®g. 8). Anterior border of mesoscu- 0.12 mm. Median and parapsidal lines rela- tum broadly rounded (®g. 8), anterior ex- tively strong. Basal vein distad cu-a by about tremity rising well above pronotum but not two times vein width; 1m-cu distad 1rs-m by overhanging, anterior vertical surface curv- about vein width; 2rs-m distad 2m-cu by ing gently onto dorsal surface; tegula oval; about four times vein width, 2rs-m arched metanotum not tomentose. preeÈpisternal (not straight); ®rst submarginal cell about as groove present and strong below level of long as combined lengths of second and third scrobal groove. Probasitibial comb absent; submarginal cells; second submarginal cell malus short, slightly shorter than velum, with slightly narrowed anteriorly; anterior border long, thin pectinate teeth; claws with short of second submarginal cell equal to that of inner tooth (®g. 16); arolium present; meta- third submarginal cell; posterior border of basitibial plate with strong borders, narrowly third submarginal cell approximately 1.5 triangular (®g. 14); inner hind tibial spur pec- times longer than anterior border. tinate, ®ve long teeth (not including apex) Clypeus with coarse, faint punctures, (®g. 15); metabasitarsus with distal process punctures separated by a puncture width or and penicillus. Basal vein strongly arcuate less and integument between faintly imbri- (®g. 13); marginal cell apex feebly truncate cate on apical third, remainder of clypeus and appendiculate; three submarginal cells with smaller, well-de®ned punctures separat- (®g. 13); both m-cu crossveins entering third ed by a puncture width or less and integu- submarginal cell (®g. 13); ®rst submarginal ment between smooth. Supraclypeal area cell about as long as combined lengths of second and third submarginal cells; distal sculptured as on upper two-thirds of clypeus. wing veins strong. Basal area of propodeum Face with similar punctures as those on su- with strong striae radiating to apical margin praclypeal area except separated by less than (®g. 8), not strongly declivitous (nearly hor- a puncture width, in most places punctures izontal); ridge between basal and posterior nearly contiguous; integument between surfaces rounded; no carinae on lateral mar- punctures smooth; punctures slightly smaller gins of posterior surface. Metasoma with to- near ocelli. Vertex and gena with minute mentum; T1 broader than long; terga without punctures separated by a puncture width or setal bands (basal or apical); tergal graduli slightly more, integument between smooth. slightly lamellate; metasoma without inte- Postgena faintly imbricate with a few widely gumental banding; pseudopygidial area not scattered coarse punctures. Pronotum cleft. smooth; mesoscutum with well-developed ETYMOLOGY: The new genus-group name punctures separated by 1±2 times a puncture is a combination of electrum (L. meaning width except around median line punctures ``amber'') and -lictus (root of the type genus slightly more sparse, separated by 2±3 times of the Halictini, Halictus). The name is mas- a puncture width, integument between culine. smooth; tegula smooth except inner margin bordering mesoscutum with minute punc- Electrolictus antiquus, new species tures separated by less than a puncture width; Figures 8±16 scutellum sculptured as on mesoscutum; me- Plate 1a,b tanotum rugulose. PreeÈpisternum with coarse DIAGNOSIS: As for the genus. punctures, punctures nearly contiguous, in- DESCRIPTION: Female. Total body length tegument between smooth when evident; 40 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 9±12. Head of holotype female of Electrolictus antiquus, new species. 9. Dorsofrontal view. 10. Left lateral view. 11. Ventral view. 12. Frontal view. Scale bars ϭ 1mm(aϭ ®gs. 9, 10, 12; b ϭ ®g. 11). mesepisternum sculptured as on preeÈpister- tured and faintly imbricate along posterior num except hypoepimeral area with smaller half. Terga and sterna imbricate. punctures separated by a puncture width or Head and mesosoma dark brown to black less; metepisternum sculptured as on hypoe- with weak metallic highlights; tegula dark pimeral area although punctures slightly brown. Legs dark brown. Wing membrane transversely elongate. Basal area of propo- hyaline; veins strong and dark brown. Me- deum with strong striae radiating from basal tasoma uniformly dark brown, without inte- margin, striae reaching to apical margin of gumental banding. dorsal surface, integument between smooth Mandible with moderate length, simple se- and shining; lateral surface minutely punc- tae scattered along lower margin and on out- 2001 ENGEL: BALTIC AMBER BEES 41

Fig. 13. Forewing of holotype female of Elec- trolictus antiquus, new species. Scale bar ϭ 1 mm. er surface. Clypeus with apical ®mbria of simple setae; face, supraclypeal area, and surface of clypeus with short to moderate length, subappressed to suberect, scattered setae each with a few minute branches; setae Figs. 14±16. Leg structures of holotype fe- more sparse on vertex. Gena with subappres- male of Electrolictus antiquus, new species. 14. Metabasitibial plate. 15. Inner metatibial spur. 16. sed short, scattered setae each with a few mi- Claw, arolium, distitarsus, and apical two seg- nute branches. Postgena with widely scat- ments of mediotarsus. Scale bars ϭ 0.5 mm (a ϭ tered, simple setae of moderate length. Me- ®g. 14; b ϭ ®gs. 15, 16). soscutum with widely scattered, erect, moderate-length setae, each with minute branches; tegula with minute, appressed, simple setae along inner half; scutellum with DIAGNOSIS: This family is a typical short- scattered, long setae, each with numerous tongued bee lineage with the cylindrical la- minute branches; metanotum with setae as on bial palpus segments and elongate jugal lobe; scutellum. Mesepisternum with scattered, the latter, plesiomorphic character distin- moderate-length, suberect setae, each with guishing the group from the Melittidae. Pa- several minute branches; metepisternum with leomelittidae also differs from the melittids sparse, minute, simple, erect setae. Scopa of by the entirely complete scrobal groove (pre- metafemur with long, plumose setae; similar sent only posterior to episternal scrobe and setae on metatibia although more dense. Lat- reaching to anterior suture of metepisternum eral and posterior surface of propodeum with in Melittidae). Unlike the basic short- sparse, long, simple setae. Terga without to- tongued families, however, Paleomelittidae mentum, instead, with sparse, simple, subap- has a fully exposed mesocoxa. pressed, short setae; sterna with similar pu- DESCRIPTION: Single subantennal suture bescence except setae slightly longer and re- (i.e., subantennal areas absent) meeting inner, stricted to apical halves. lower margin of antennal socket. Facial fo- MATERIAL: One specimen. Holotype. Fe- veae absent. Segments one and two of labial male, MB.I.1952 (ZMHB): labeled ``Holo- palpi similar to distal segments, cylindrical, type, Electrolictus antiquus Engel'' // ``Mu- distal segments in line with basal segments; seum fuÈr Naturkunde Berlin, PalaÈontolo- glossa acute, short, without ¯abellum; stipital gisches Museum, Slg. KuÈhl 23 (3/12), Inv. concavity and comb absent; galeal comb ab- Nr. MB.I.1952'' // ``Halictidae: Halictinae, sent. PreeÈpisternal groove incomplete, absent det. M. S. Engel, 1999''. below level of scrobe; scrobal groove present ETYMOLOGY: The speci®c epithet is the and entire (i.e., present both in front of as Latin word antiquus meaning ``ancient'' and well as posterior to episternal scrobe). Me- is a reference to this being the oldest record socoxa fully exposed, exposed area slightly of an amber halictid. longer than distance from summit to metathoracic wing base; metabasibitial plate pre- PALEOMELITTIDAE, New Family sent; scopa developed on metafemur (more TYPE GENUS: Paleomelitta Engel, new ge- weakly than on following leg segments), me- nus. tatibia, and metabasitarsus, scopa strongest 42 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 on metatibia. Jugal lobe of hind wing much more than half as long as vannal lobe. COMMENTS: Paleomelittidae occupies an interesting position intermediate between the basic short-tongued families (Colletidae, Halictidae, and Andrenidae) and the ``Mel- ittidae ϩ long-tongued families'' complex. The family has the fully exposed mesocoxa typical of melittids and long-tongued bees and is therefore closer to this group than to other basic short-tongued families. It could be retained as the basalmost subfamily of Melittidae but this would render the melittids paraphyletic and I have therefore accorded the group family rank.

Paleomelitta, new genus

TYPE SPECIES: Paleomelitta nigripennis Engel, new species. DIAGNOSIS: As for the family (see above). Fig. 17. Frontal view of head of holotype fe- Paleomelitta has the general habitus of Da- male of Paleomelitta nigripennis, new species. sypoda species and the forewing venation of Scale bar ϭ 1 mm. the two genera is somewhat similar in many respects (except in dasypodaines 1m-cu is fringe of elongate, simple setae (®g. 18); scu- not strongly apicad the second abscissa of tellum rising well above metanotum then Rs). Paleomelitta can be separated from Da- abruptly curving behind posterior fringe to sypoda by the above familial characters as meet metanotal basal border, not projecting well as those presented below in the generic over metanotum. Metabasitibial plate pre- description (most notably the absence of a sent, large, and strongly bordered on all edg- metabasitibial plate in Dasypoda is signi®- es; scopal setae simple; claws with short in- cantly different from Paleomelitta where this ner tooth (®g. 19); arolium present and large structure is large and well developed). (®g. 19). Marginal cell apex set away from DESCRIPTION: As for the family with the wing margin by approximately three-quarters following additions: Labrum with two short, of pterostigma width, feebly appendiculate medial tubercles on basal surface (®g. 17), (®g. 20). Margin of pterostigma inside of about 2.5 times wider than long, without dis- marginal cell slightly convex; pterostigma tal process. Mandible broad at base and ta- longer than wide; r-rs arising in apical half pering rapidly to apex, strongly bent inward of pterostigma. Two submarginal cells; sec- near midpoint, with strong subapical tooth ond abscissa of Rs approximately orthogonal (®g. 17). Malar space short, much shorter to M, strongly basad of 1m-cu (®g. 20). than basal mandibular width. Clypeus slight- ETYMOLOGY: The new genus-group name ly concave medially on central disc, apical is a combination of palaios (Greek, meaning margin with distinct medial tubercle laterally ``ancient'') and melitta (Greek, meaning bordered by tufts of elongate, erect setae ``bee''). The name is feminine. (tufts composed of three setae each: ®g. 17); epistomal sulcus forming an obtuse angle; Paleomelitta nigripennis, new species apical quarter of clypeus set below lower tangent of compound eyes. Inner margins of Figures 17±20 compound eyes approximately parallel. F1 Plates 1c,d, 2a longer than F2 (®g. 17); F3 slightly longer DIAGNOSIS: As for the genus. than F2. Vertex short, ca. 1.5 OD in length DESCRIPTION: Female. Total body length (®g. 18). Posterior margin of scutellum with 14.65 mm; forewing length 10.50 mm. Head 2001 ENGEL: BALTIC AMBER BEES 43

Fig. 18. Dorsal view of mesosoma, posterior border of prosoma, and anterior border of metasoma of holotype female of Paleomelitta nigripennis, new species. NOTE: The depicted incision in the hind wing is the jugal fold demarcating the apical margin of the jugal lobe; the vannal fold is positioned just under the posterior edge of the forewing. Scale bar ϭ 1 mm. wider than long (length 3.25 mm, width 4.03 praclypeal area, face, vertex, and gena sculp- mm). Compound eye width approximately tured as on basal half of clypeus. Pronotum twice that of gena. Interocellar distance 0.60 smooth and impunctate. Mesoscutum with mm; ocellocular distance 0.50 mm; median small punctures separated by 1±2 times a to lateral ocellus 0.15 mm. Median and par- puncture width except around median line apsidal lines strongly impressed (®g. 18). In- separated by a puncture width or less, integ- tertegular distance 3.05 mm; mesoscutum ument between smooth. Scutellum sculptured length 1.05 mm; scutellum 2.5 times longer as on mesoscutum except punctures separat- than metanotum; basal area of propodeum ed by 2±3 times a puncture width. Tegula about as long as metanotum. Basal vein ba- with minute punctures separated by less than sad cu-a by vein width; second abscissa of a puncture width on inner half, outer half im- Rs basad 1m-cu by four times vein width, punctate, integument between ®nely imbri- straight, approximately orthogonal to M (®g. cate. Metanotum imbricate. Pleura with 20); 2rs-m distad 2m-cu by two times vein sparse, minute punctures, integument be- width; ®rst submarginal cell subequal to sec- tween smooth. Propodeal lateral and poste- ond submarginal cell; posterior border of rior surfaces ®nely imbricate; basal area of second submarginal cell approximately 1.25 propodeum strongly imbricate. Metasomal times length of anterior border. terga with minute punctures separated by a Labrum with small punctures separated by puncture width, integument between ®nely a puncture width or less, integument between imbricate; sterna imbricate. smooth. Clypeus with small punctures sepa- Coloration dark brown. Wing membranes rated by 1±2 times a puncture width on api- exceedingly infumated, dark brown; veins cal half, basal half punctures smaller, faint black. and sparse, integument between smooth. Su- Pubescence fuscous. Labrum with scat- 44 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 20. Forewing of holotype female of Pa- leomelitta nigripennis, new species. Scale bar ϭ 1 mm.

tae; basal area of propodeum without setae. Metafemur without scopal setae; metatibia and metabasitarsus with scopae composed of dense, elongate, simple setae, setae longest on inner surfaces (3±4.5 OD). Anterior-facing surface of T1 with widely spaced, erect setae (2 OD), each with a few minute branches; remaining terga and apical margin of T1 with scattered, minute, simple, appressed setae; sterna with scattered, simple, erect, post- Fig. 19. Distitarsus, claw, and arolium of holotype female of Paleomelitta nigripennis, new gradular setae. species. Upper image is an outer view; lower im- MATERIAL: Two specimens. Holotype. Fe- age is an inner view. Scale bar ϭ 0.25 mm. male, B-JH 101 (AMNH) labeled: ``Baltic amber: Eocene, Kaliningrad, Yantarny'' // ``Holotype, Paleomelitta nigripennis Engel''. tered, short (ca. 1 OD or less), erect, simple The block of amber containing the two bees setae. Clypeus and supraclypeal area with is an impressive size (pl. 2a) and measures scattered, short, suberect, simple setae; clyp- approximately 13.5 cm in length, 5.5 cm in eus with two submedial patches of three (2 width, and 3.75 cm in height. OD in length) simple setae (®g. 17). Face, Paratype. Female, in same piece of amber vertex, and gena with scattered, simple, erect as holotype (see above). to suberect, short (1 OD in length) setae; se- ETYMOLOGY: The speci®c epithet is a com- tae of gena progressively longer toward post- bination of the Latin words nigra (meaning gena (reaching 3 OD in length). Pronotum ``black'') and penna (meaning ``wing'') and with sparse, minute, suberect, simple setae is a reference to the darkened membrane of except surface at dorsolateral angle and pron- the forewings. otal lobe with dense, plumose setae (1 OD). Mesoscutum with scattered, minute, erect, Family MELITTIDAE Schenck simple setae, setae sparse on central disc but more noticeable along borders. Scutellar pu- Melittidae Schenck, 1860: 136. Type genus: Mel- itta Kirby, 1802. bescence as described for mesoscutum except posteriorly fringed with dense, plumose DIAGNOSIS: This family consists of short- setae; axilla with more elongate (1.5±2 OD), tongued bees with the fully exposed meso- simple, erect setae. Metanotum with scat- coxa, V-shaped submentum, and short jugal tered, short, suberect to erect, simple setae. lobe typical of the long-tongued bees while Pleura with scattered, simple, erect setae retaining the plesiomorphic ``short-tongued'' (1.5±2 OD) except hypoepimeral area with- labial structure, absence of a stipital comb out setae. Lateral and posterior surfaces of and concavity, and absence of a ¯abellum. propodeum with scattered, short, simple se- Melittids also lack a preeÈpisternal groove and 2001 ENGEL: BALTIC AMBER BEES 45 the scopa is limited to the metatibia and me- TABLE 6 tabasitarsus. Hierarchical Supraspeci®c Classi®cation of DESCRIPTION: Labrum frequently much Melittidae wider than long, apical margin fringed with (Currently recognized genera included bristles. Single subantennal suture; suture but subgenera excluded.) meets lower margin of antennal socket frequently at midpoint, although sometimes slightly laterad midpoint (either outer or inner side of lower margin), never meeting outer margin of antennal socket. Facial foveae absent. Lower lateral margin of clypeus not bent posteriorly on either side of labrum. Fla- bellum absent; glossa acute; glossal rod absent; paraglossa frequently reduced, sometimes absent; labial palpus with ®rst two segments cylindrical, not sheath-like, third and fourth segments in line with preceding segments, not projecting laterally. Mentum elongate, tapering basally, curved over submentum to its articulation; apex of mentum articulated with prementum via fragmentum; submentum strongly V-shaped and sclerotized, submental arms articulating with cardines slightly above cardo-stipital articulations. Galeal blade equal or shorter than stipes, frequently longer than prepalpal section of galea; galeal comb present; stipital comb and concavity absent; basistipital process elongate. PreeÈpisternal groove absent. Me- socoxa entirely exposed. Metabasitibial plate frequently distinct. Scopa restricted to metatibia and metabasitarsus. Jugal lobe of hind wing one quarter to one half as long as vannal lobe. Metapostnotum without pubescence. Pygidial plate and ®mbria of female present; pygidial plate of male frequently absent. Volsella present; penis valves do not form a distinct spatha. tribe Redivivini (new tribe; type genus: Re- COMMENTS: The subfamily Melittinae diviva Friese) with Rediviva and Redivivo- (sensu Michener, 1981b) contains three dis- ides. The Redivivini can be separated from tinct groups that are not closely af®liated; Melittini by the reduced, shining, and smooth each has numerous characters separating propodeal triangle and males with S7 bi®d them from one another as much as the re- (Michener, 1981b). Table 6 summarizes a maining subfamilies of the family. Herein I new higher classi®cation of Melittidae. have separated Macropis from the subfamily The separation of Macropis from the Mel- Melittinae and resurrected the subfamily Ma- ittinae implies that the oil-collecting struc- cropidinae; I have here added a second genus tures of the Macropidini and the Redivivini to this subfamily (described below). Like- arose independently. This seems to be a valid wise, the African genera Rediviva and Redi- conclusion since macropidines appear to vivoides, while retained in Melittinae, are re- share features with basal dasypodaines (e.g., stricted to their own tribe. The Melittinae is Promelitta) particularly in the presence of therefore reduced to two groups: tribe Mel- only two submarginal cells and, in fact, the ittini with Melitta s.l. and Dolichochile, and structure of the second abscissa Rs in basal 46 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 dasypodaines is dif®cult to distinguish from biconcave (straight in Macropidini), posterior the state seen in Macropidinae. border rising well above metanotum (®g. 22) (not gently curving over to meet metanotum Subfamily MACROPIDINAE Robertson as in Macropidini). Metanotum strongly convex, with median longitudinal carina (®g. Macropididae Robertson, 1904: 42. Type genus: 22). Protarsi and mesotarsi not thickened, Macropis Panzer, 1809. without dense, velvety setae; metatibia and DIAGNOSIS: This subfamily resembles the metabasitarsus thin and elongate (not broad Dasypodainae by the presence of only two as in Macropidini), metabasitarsus at least submarginal cells in the forewing (i.e., loss three times longer than wide (®g. 24); me- of 1rs-m). In dasypodaines, however, the sec- tatibia without oil-collecting setae; metabas- ond abscissa of Rs is not widely separated itibial plate strong, broadly rounded (®g. 25); from 1m-cu and is essentially orthogonal to metabasitarsus with setae present on distal M. From Melittinae, in the restricted sense process; metabasitarsal setae unmodi®ed. that I have used it here, macropidines differ Vein r-rs arising distad middle of pterostigma by the reduced number of submarginal cells, (®g. 23). Propodeum strongly V-shaped, dor- the presence of yellow maculations on the sal-facing surface not transverse. face of males, and the presence of a pygidial plate in males. Eomacropis, new genus DESCRIPTION: Mandible with strong subapical tooth. Two submarginal cells, cells TYPE SPECIES: Eomacropis glaesaria En- subequal in length; second abscissa of Rs gel, new species. slightly oblique, widely separated from 1m- DIAGNOSIS: As for the tribe (see above). cu. Pygidial and prepygidial ®mbriae strong. DESCRIPTION: Galea with long setae at Males with yellow maculations on the clyp- apex; maxillary palpus six-segmented (basal eus; males with pygidial plate present. segment not visible in ®gure 21 but is visible COMMENTS: The subfamily as presently de- from a lateral view of the head). Width of ®ned contains two genera (Macropis and labrum three times greater than length; sur- Eomacropis), which I have segregated into face impunctate; short, median, distal process two monobasic tribes. This is owing to the with long setae along margins. Malar space numerous, signi®cant differences between linear, length much less than basal mandib- the two genera, each with several apomorph- ular width, base of mandible nearly touching ic traits supporting their respective monophy- lower margin of compound eye. Mandible ly. They are suf®ciently different to warrant with strong subapical tooth. Epistomal sulcus placement in different tribes. forming approximately orthogonal angle (®g. 21). F1 longer than F2 (®g. 21). Compound eye weakly emarginate above level of anten- EOMACROPIDINI, New Tribe nal sockets (®g. 21); compound eyes without TYPE GENUS: Eomacropis Engel, new ge- setae. Gena slightly broader than compound nus. eye in lateral view. Preoccipital area sharply DIAGNOSIS: This tribe differs from Macro- angled but not carinate. Scrobal groove pre- pidini most notably by the complete absence sent. Claw with inner tooth, arolium present of the suite of oil-collecting adaptations seen (®g. 24); metatibial and metabasitarsal scopa in Macropis (e.g., velvety setae on thickened composed of densely plumose setae; setae of tarsi). Eomacropidini has an elongate meta- apical truncation of metabasitarsus not parted basitarsus and vein r arises distad the middle to expose narrow strip of integument. Basal of the pterostigma. The apomorphic presence vein straight, basad cu-a, basal vein twice as of a strongly convex and medially carinate long as ®rst abscissa of Rs (®g. 23); prestig- metanotum and V-shaped propodeum is im- ma shorter than margin of pterostigma inside mediately diagnostic. of ®rst submarginal cell, prestigma about as DESCRIPTION: Labrum without median wide as pterostigma; pterostigma inside of transverse ridge, with subapical elevation marginal cell slightly convex (®g. 23). Basal (®g. 21). Anterior border of scutellum gently area of propodeum impunctate, granular and 2001 ENGEL: BALTIC AMBER BEES 47

Figs. 21±22. Holotype female of Eomacropis glaesaria, new species. 21. Frontal view of head. 22. Right dorsolateral oblique view of mesosoma, posterior border of prosoma, and anterior border of metasoma. NOTE: Staphyliniform beetle larva on mesoscutum of the holotype. Scale bars ϭ 1mm(a ϭ ®g. 22; b ϭ ®g. 21). without pubescence (plesiomorphically sim- tennal sockets to approximately 1 OD from ilar in this respect to Macropis s.s.). median ocellus. Upper interorbital distance ETYMOLOGY: The new genus-group name 1.65 mm; lower interorbital distance 1.55 is a combination of eo- (a reference to the mm. Interocellar distance 0.35 mm; ocello- epoch name, Eocene) and Macropis, type ge- cular distance 0.4 mm; median to lateral nus of the Macropidinae. The name is fem- ocellus 0.15 mm. Scutellum slightly less than inine. twice length of metanotum; metanotum slightly longer than basal area of propodeum. Eomacropis glaesaria, new species Malus serrate; distal section of protibial spur Figures 21±25 beyond velum slightly shorter than section of Plate 1e,f spur bordering velum. Intertegular distance DIAGNOSIS: As for the genus (see above). 1.9 mm. Second abscissa of Rs strongly ba- DESCRIPTION: Female. Total body length sad 1m-cu (®g. 23); 2rs-m distad 2m-cu by 12.4 mm; forewing length 10.1 mm. Head three times vein width; ®rst submarginal cell slightly wider than long (length 2.65 mm, slightly shorter than second submarginal cell; width 2.85 mm). Distal half of clypeus ex- eight distal hamuli, arranged in a single tending below lower tangent of compound evenly spaced series. eyes (®g. 21). Frontal line carinate from an- Labrum with minute, scattered punctures, 48 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 2001 ENGEL: BALTIC AMBER BEES 49 integument between smooth. Clypeus with va on its dorsum (®g. 22, pl. 1f). Presumably sparse, faint, coarse punctures. Face with the two insects were accidentally preserved small punctures separated by a puncture together, as there is no such association width, integument between smooth. Vertex known among living bees today; this, how- with punctures becoming faint, coarse, and ever, does not preclude such an association sparsely distributed. Gena sculptured like in the past. Moreover, the beetle is simply face. Postgena imbricate and impunctate. too large to have been carried by the bee in Mesoscutum and scutellum with small punc- the same manner as bees carry triungulin tures separated by a puncture width or less, meloids. integument between smooth. Tegula impunctate and smooth. Metanotum rugulose. Pleura LONG-TONGUED BEES with small punctures separated by a puncture Family MEGACHILIDAE Latreille width or less, integument between smooth. Terga and sterna imbricate. DIAGNOSIS: The megachilids are most no- Head dark brown to black with light table for the development of the scopa on the brown to yellowish marks lateral to clypeus metasomal sterna [subsequently reduced on and near lower, inner margin of compound the hind legs in Lithurginae (tribe Lithurgini) eyes. Mesosoma dark brown to black; legs and Megachilinae; see below] and the struc- dark brown. Wing membrane lightly fuscous; ture of the subantennal suture which meets veins dark brown. Metasoma dark brown. the outer margin of the antennal socket in Labrum with scattered, short, erect, simple Lithurginae and Megachilinae. The labrum is setae. Face with scattered, short, suberect, broadly articulated to the head capsule and simple setae. Postgena with moderate-length, in all except some Fideliinae and the fossils erect, simple setae. Mesoscutum with mod- discussed below it is longer than broad. erate-length, erect, simple seate, a few with DESCRIPTION: Labrum broadly articulated minute branches. Scutellum with pubescence to clypeus, frequently longer than wide. Sin- as described for mesoscutum except setae gle subantennal suture; suture meets lower longer and with more numerous branches margin of antennal socket in Fideliinae, along posterior border. Metanotum with meets outer margin of antennal socket in Me- short, scattered setae each with minute gachilinae and Lithurginae. Facial foveae ab- branches. Pleura with scattered, long, simple sent. Lower lateral margins of clypeus not setae, a few with branches, setae becoming bent posteriorly on either side of labrum. Fla- progressively longer and more dense ven- bellum present; glossa acute; labial palpus trally. Scopa on metatibia and metabasitarus with ®rst two segments ¯attened, sheath-like, composed of dense, long, plumose setae; me- and elongate; submentum strongly V-shaped tafemur with long, branched setae on upper and sclerotized, submental arms articulating and anterior border. Terga with sparse, mi- with cardines slightly above cardo-stipital nute, simple setae; sterna with scattered, articulations. Galeal comb absent; stipital long, simple setae. comb and concavity present; basistiptial pro- MATERIAL: One specimen. Holotype. Fe- cess elongate. PreeÈpisternal groove absent. male (SAMH) labeled: ``Holotype, Eomacro- Mesocoxa entirely exposed. Metabasitibial pis glaesaria Engel''. plate variable (present in Protolithurgini and ETYMOLOGY: The speci®c epithet is de- some Lithurgini along posterior margin; ab- rived from the Latin word glaesarius (mean- sent in Fideliinae and Megachilinae). Jugal ing ``of amber''). lobe short. Metasomal scopa present (in non- COMMENTS: The holotype of Eomacropis parasitic females). Metapostnotum setose. is preserved with a staphyliniform beetle lar- Pygidial plate and ®mbria of female present

← Figs. 23±25. Holotype female of Eomacropis glaesaria, new species. 23. Forewing. 24. Inner surface of metatibia and metatarsus. 25. Outer surface of metatibia, apex of metafemur, and basal portion of metabasitarsus. Scale bars ϭ 1mm(aϭ ®g. 23; b ϭ ®gs. 24, 25). 50 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 in Fideliinae and Lithurginae, absent in Me- TABLE 7 gachilinae. Hierarchical Suprageneric Classi®cation of COMMENTS: The family Megachilidae con- Megachilidae sists of three subfamilies: Fideliinae, Lithur- ginae, and Megachilinae (see table 7). The ®deliines have at times been accorded family rank (e.g., Moure and Michener, 1955; Mich- ener and Greenberg, 1980). Within the family the scopa on the hind legs has generally been reduced (owing to the use of the metasomal scopa). It would appear that the scopa of the hind legs has been primitively retained in Fideliinae and an extinct tribe of Lithurginae (Protolithurgini; see below); however, these setae are not used for the transport of pollen (like other megachilids, pollen is transported in the metasomal scopa) and are instead used in ¯inging sand during nest building (Rozen, 1970, 1973). Thus, these setae in ®deliines are not a true scopa.

Key to Subfamilies of Megachilidae in Baltic Amber 1. Metabasitibial plate present (represented solely along posterior border in living taxa); T1 short and ¯at in pro®le; pygidial plate present (sometimes reduced to strong apical spine) ...... Lithurginae Newman ± Metabasitibial plate absent; T1 not short- cies with three or more teeth, typically short ened, convex in pro®le; pygidial plate ab- and robust. Subantennal sutures directed to sent ...... Megachilinae Latreille outer margins of antennal sockets. Outer surfaces of tibiae with hairless spicules (except Subfamily LITHURGINAE Newman in Protolithurgus and some males of recent DIAGNOSIS: The Lithurginae can be im- species); metabasitibial plate present; meta- mediately differentiated by the short, ¯at ®rst basitarsus slender and cylindrical (except in metasomal tergum and the presence of both Protolithurgus). Forewing with two submar- metabasitibial and pygidial plates. From the ginal cells; jugal lobe of hind wing half or Fideliinae it differs by the presence of only more as long as vannal lobe. Metasomal T1 two submarginal cells, the reduced seventh shortened, ¯attened in pro®le, posterior mar- sternum in males, and the fusion or loss of gin rounded. Pygidial plate and pygidial ®m- volsellae. Megachilines have lost the meta- bria present. Females typically with a facial basitibial and pygidial plates and have a lon- prominence below antennal sockets, com- ger ®rst metasomal tergum that is convex in posed of either clypeus or supraclypeal area pro®le. Extant lithurgines can further be rec- (all species of Microthurge, nearly all Li- ognized by their distinctly spiculate tibiae thurgus, and a few Trichothurgus). and elongate glossae. COMMENTS: Although classically given su- DESCRIPTION: Proboscis elongate, often bfamilial rank (e.g., Michener, 1944, 1983; reaching metasoma in repose (only in the ex- Moure, 1949), the group has recently been tant tribe Lithurgini); third segment of labial downgraded to a tribe at the base of the larg- palpus ¯attened, on same axis as second seg- er subfamily Megachilinae (Michener, ment. Labrum longer than broad (except in 2000a). This has its advantages by empha- Protolithurgus where the length is apparently sizing that lithurgines share more characters equal to the width). Mandibles in recent spe- in common with the megachilines and that 2001 ENGEL: BALTIC AMBER BEES 51 the difference between the Fideliinae and the surfaces of tibiae not spiculate; metabasiti- remainder of Megachilidae (i.e., Lithurginae bial plate present, strongly bordered on all and Megachilinae) is great. However, the li- sides (®g. 28); metatibia with weakly formed thurgines are just as distinctive in their own scopa in addition to metasomal scopa; me- right, with numerous great differences from tabasitarsus ¯attened; female claw cleft (®g. the Megachilinae, while differences among 29); female arolium present (®g. 29). the megachiline tribes are far less signi®cant. COMMENTS: The Protolithurgini is signi®- Thus, since the monophyly of the groups is cant among lithurgines for retaining the ple- well established, the recognition of the li- siomorphic condition of a relatively short thurgines as a separate subfamily seems well glossa, bidentate mandibles, and metatibial warranted and of some use to emphasize scopa (as well as a metasomal scopa). It can their biological and morphological separation be con®dently classi®ed in the Lithurginae from the Megachilinae. Therefore, I here re- owing to the apomorphic presence of the turn them to subfamilial rank within the Me- shortened and ¯at ®rst metasomal tergum gachilidae. The subfamily Lithurginae is dis- (unique to lithurgines among the Megachili- tributed throughout the world with its great- dae), the third labial palpus on the same axis est diversity in arid regions of South Amer- as the second, and the retention of a meta- ica. basitibial plate (although even more well de- The subfamily has not previously been re- veloped than in extant lithurgines). corded from any amber deposit and, although Protolithurgus, new genus one compression fossil has been assigned to Lithurgus, de®nitive lithurgines are not TYPE SPECIES: Protolithurgus ditomeus En- known from the geological record. Lithurgus gel, new species. adamiticus (Heer), a compression fossil from DIAGNOSIS: Labrum apparently as long as the Miocene of Oeningen, was originally wide, with numerous, erect setae on surface. proposed as a species of honey bee (Heer, Mandible not short and stout (as is typical for extant lithurgines), with only two strong- 1865). Cockerell (1909a) later transferred the ly developed teeth (®g. 26). Clypeus not ex- species to Lithurgus on the basis of overall tending below lower tangent of compound body shape and wing venation. In actuality, eyes (®gs. 26, 27); epistomal sulcus forming the fossil does not preserve characters that a slightly obtuse angle; supraclypeal area would de®nitively assign it to this subfamily. convex, gently swollen and protuberant in Thus, the amber inclusion described below is lateral view, extending above level of clyp- the ®rst de®nitive fossil lithurgine and serves eus (®g. 27). Subantennal sutures meeting as both the oldest record of the subfamily outer margin of antennal sockets (®g. 26); F1 and the only one preserved in amber. distinctly longer than F2 (®g. 26). Compound A hypothesis of generic relationships with- eyes not emarginate, inner margins parallel in the Lithurginae, Recent and fossil, is pre- (®g. 26). Preoccipital ridge rounded. Tibiae sented below (see Cladistic Analyses). not spiculate; metabasitibial plate present, strongly bordered on all sides, large and PROTOLITHURGINI, New Tribe broadly rounded (®g. 28); claws cleft (®g. 29); arolium present (®g. 29). Metasomal TYPE GENUS: Protolithurgus Engel, new scopa strong and present; T1 relatively short, genus. ¯at in lateral view. DIAGNOSIS: This group can be readily sep- ETYMOLOGY: The new genus-group name arated from its living sister taxon, the Li- is a combination of protos (Greek, ``®rst'') thurgini, by the large, strongly bordered me- and the genus name Lithurgus, type genus of tabasitibial plate, the ¯attened metabasitar- the subfamily. The name is masculine. sus, the bidentate mandibles, the absence of metatibial spicules, and the relatively short Protolithurgus ditomeus, new species labrum. Figures 26±29 DESCRIPTION: Third labial palp segment on Plate 2b±d same axis as second. Labrum about as long DIAGNOSIS: As for the genus (see above). as wide. Mandible bidentate (®g. 26). Outer DESCRIPTION: Female. Preserved body 52 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 26±29. Holotype female of Protolithurgus ditomeus, new species. 26. Frontal view of head. 27. Right lateral view of head. 28. Outer surface of metatibia. 29. Inner view of claw and arolium. Scale bars ϭ 1mm(aϭ ®g. 26; b ϭ ®g. 27; c ϭ ®gure 28; d ϭ ®g. 29). 2001 ENGEL: BALTIC AMBER BEES 53 length 12.86 mm (from head to approxi- metasomal sterna with scopa, sterna with mately the basal portion of T5). Head wider dense, elongate (4±5.5 OD), simple, erect se- than long (length 3.10 mm, width 4.40 mm). tae, setae with sinuous apices. Clypeus not extending below lower tangent MATERIAL: One specimen. Holotype. Fe- of compound eyes; convex and somewhat male, B-W 157 (AMNH) labeled: ``Baltic protuberant in lateral view (®g. 27). Upper amber: Eocene, Kaliningrad, Yantarny'' // interorbital distance 2.35 mm; lower inter- ``Holotype, Protolithurgus ditomeus Engel''. orbital distance 2.37 mm. Interocellar dis- The caudal end of the holotype of Protoli- tance 0.55 mm; ocellocular distance 0.60 thurgus is badly damaged. The apex of the mm; median to lateral ocellus 0.15 mm. In- wings and metasoma reach to the amber sur- tertegular distance 3.38 mm. Scutellum face where the amber becomes extremely slightly more than three times length of me- turbulent (numerous, strong, bending ¯ow tanotum; metanotum about as long as basal lines). The apices of the wings are missing area or propodeum. Basal vein basad by vein as is, apparently, the apex of the metasoma. width, straight; ®rst submarginal cell appar- The apical halves of the forewings appear as ently subequal in length to second submar- though they have been cleared and even heat- ginal cell. ed during preservation (while the resin was Labrum, clypeus, supraclypeal area, face, still soft). Although the veins are no longer vertex, gena, and postgena imbricate. Meso- pigmented the membrane of the wing is still soma imbricate. Metasoma apparently preserved (the minute setae of the wing (where evident) imbricate. membrane can be easily seen at higher mag- Head and mesosoma brown with nonme- ni®cation) and by slowly searching the wing tallic, greenish highlights; antennae, meta- membrane it is possible to locate the rem- soma, and legs dark brown without high- nants of veins and to follow their courses. lights. Wing membrane fuscous; veins dark Thus, it is possible to determine to some de- brown to black. gree what the forewing venation of this spe- Pubescence fuscous to black. Labrum with cies had been. It is also dif®cult to examine numerous, long (2±2.5 OD), simple, erect se- T1 but its apical margin can be seen from tae, setae not obscuring integument. Clypeus, above and between the bases of the fore- supraclypeal area, and face below level of wings (which are folded over the metasoma) antennal sockets with scattered, simple, erect, as well as in lateral view. long (2±3 OD) setae; clypeal margin with ETYMOLOGY: The speci®c epithet is a ref- submedial patch of setae; face above level of erence to the two teeth of the mandible by antennal sockets, vertex, and gena with setae comparison to the three teeth of Recent li- sparser and shorter (1 OD). Postgena with thurgines (Gr. di, meaning ``two'', and to- long (2±3.5 OD), erect, simple setae. Pron- meus, meaning ``tooth''). otum with minute, sparse, simple setae ex- COMMENTS: The holotype of Protolithur- cept dorsolateral angle with plumose (1 OD) gus ditomeus has at least eight triungulin setae. Mesoscutum with minute, sparse, sim- meloids hanging onto seta of the mesosomal ple setae. Scutellum as described for mesos- venter as well as one attached to a seta of cutum except axilla with patches of erect, the gena. Although a triungulin is recorded plumose (1 OD) setae. Metanotum without by Larsson (1978) in Baltic amber, the spec- setae. Hypoepimeral area, metepisternum, imen was found in isolation from any other and lateral surface of propodeum with sparse, insects and its identity was suspect. The suberect, simple (1 OD) setae; preeÈpisternum triungula reported here are presently the old- and mesepisternum with scattered, long (2.5± est, de®nitive record of the host-parasite as- 3 OD), erect setae each with a few short sociation between bees and meloid beetles as branches. Basal area of propodeum without well as the oldest, de®nitive fossil of a mel- pubescence. Metafemur without scopal setae; oid triungulin. metatibia and metabasitarsus with dense, simple setae, a few with two or three short Subfamily MEGACHILINAE Latreille branches. Metasomal terga apparently (where Megachiles Latreille, 1802b: 381. Type genus: evident) with sparse, minute, simple setae; Megachile Latreille, 1802a. 54 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

DIAGNOSIS: Refer to Diagnosis for subfam- are not presently well de®ned, I prefer to ten- ily Lithurginae (above). tatively recognize them as subtribes for pur- DESCRIPTION: Proboscis typically not elon- poses of comparison with the plesiomorphic gate (as in Recent lithurgines); third segment fossils discussed below. The Osmiini can of labial palpus projecting laterally from axis therefore be divided into four groups or sub- of second segment (except in some Chelos- tribes as indicated in table 7; the fossils fall toma and other groups). Labrum longer than into two distinct subtribes: Glyptapina Cock- broad (except in Glyptapina and Ctenoplec- erell and Ctenoplectrellina (new subtribe). trellina). Mandibles with a variable number of The two fossil subtribes retain a short la- teeth, typically short and robust. Subantennal brum, a plesiomorphic feature for Lithurgi- sutures directed to outer margin of antennal nae and Megachilinae; however, the presence sockets. Outer surface of tibiae frequently not of several derived characters typical of Me- spiculate (except in some Anthidiini); meta- gachilinae (e.g., complete absence of metabasitibial plate absent; metabasitarsus ¯at- basitibial plate, absence of pygidial plate) tened. Forewing with two submarginal cells suggests that this character is a reversal. Sub- (i.e., 1rs-m absent); jugal lobe of hind wing tribes of Osmiini can be distinguished as fol- short. Metasomal T1 not shortened, convex in lows (based on females only): pro®le, posterior margin straight or convex. Osmiina Newman: Maxillary palpi four- Pygidial plate and pygidial ®mbria absent. or ®ve-segmented; labrum longer than wide; mandible variously structured; parapsidal Tribe OSMIINI Newman lines punctiform (in Osmia) or linear; omau- Osmiites Newman, 1834: 401. Type genus: Osmia lar ridge rounded; basal area of propodeum Panzer, 1806. declivitous; claws simple (except in Metali- Chelostomidae Kirby, 1837: 270. Type genus: nella). Chelostoma Latreille, 1809. Trypetina Robertson, nomen translatum Glyptapinae Cockerell, 1909b: 13. Type genus: [ϭ Heriadini of Michener (1941)]: Maxillary Glyptapis Cockerell, 1909a. NEW SYNONYMY. palpi two- to four-segmented; labrum longer Trypetini Robertson, 1903: 164. Type genus: Try- than wide; mandible variously structured; petes Schenck, 1861. parapsidal lines linear; omaular ridge usually Heriadini Michener, 1941: 152. Type genus: Her- rounded (carinate in some); basal area of pro- iades Spinola, 1808. podeum usually horizontal; claws simple. DIAGNOSIS: Megachiline bees with an ar- The family-group name based on Trypetes (a olium, an elongate pterostigma, 2m-cu basad junior synonym of Heriades) has priority 2rs-m, and frequently with simple claws (ex- over that based on Heriades. The name Try- cept in the Baltic amber genera and one liv- petini cannot be dismissed simply owing to ing group). the synonymy of its type genus (ICZN, DESCRIPTION: Arolium present; claws sim- 1999b: Art. 40.1) and, thus, the subtribal ple (except cleft in Glyptapina, Ctenoplec- name should be Trypetina Robertson. trellina, and Metallinella). Pterostigma lon- Glyptapina Cockerell, nomen translatum ger than wide; 2m-cu basad 2rs-m. Integu- (includes only Glyptapis Cockerell): Maxil- ment without maculations (except in Ochrer- lary palpi four-segmented; labrum wider than iades) and frequently metallic or with long; mandible with long, upper cutting-edge metallic highlights. (®gs. 30, 32) (mandible in general structure COMMENTS: Phylogenetic af®nities among similar to some species of Anthidiini; e.g., osmiine genera are unclear and dif®cult to some Dianthidium); parapsidal lines linear; resolve. The tribe is very likely paraphyletic omaular ridge strongly carinate (as in some with respect to at least the Megachilini. Old World Anthidiini); basal area of propo- Michener (1941) attempted to divide the deum declivitous; claws cleft (®g. 35). group into two tribes, the Osmiini s.s. and Ctenoplectrellina, new subtribe (type ge- the Heriadini [roughly equivalent to the Os- nus: Ctenoplectrella Cockerell; subtribe also mia- and Heriades-genus groups of Griswold includes Glaesosmia, n. gen.): Maxillary pal- (1985), Griswold and Michener (1997), and pi four-segmented; labrum wider than long; Michener (2000a)]. Although these groups mandible variously structured; parapsidal 2001 ENGEL: BALTIC AMBER BEES 55

Fig. 30. Right lateral view of head of holotype female of Glyptapis mirabilis Cockerell. lines linear; omaular ridge rounded; basal olae; mandible with three teeth, short cut- area of propodeum gently sloping, not ting edge between uppermost tooth and strongly declivitous (®g. 46); claws cleft (®g. lower two teeth (®g. 40); mesoscutum and 42). scutellum normally punctate or impunctate; It may be that Osmiini, incorporating the compound eyes bare (®g. 40) ...... 2 fossil lineages, is paraphyletic with respect ± Mesepisternum coarsely areolate and rugose (®gs. 33, 39); omaular carina present and to not only the Megachilini but the Anthidi- strong (®g. 33); propodeum strongly areo- ini as well. It is possible that Cockerell's late (®g. 31); mandible with a single, small Glyptapina (Cockerell, 1909b: Glyptapinae lower tooth and large upper cutting edge in his system) is more closely allied to An- (®g. 32); mesoscutum and scutellum coarse- thidiini, while Ctenoplectrellina is sister to ly punctate, punctures deep and craterlike living Osmiini ϩ Megachilini. Once the clas- (®gs. 31, 38); compound eyes hirsute, setae si®cation of Osmiini has been clari®ed long (®g. 32) ...... Glyptapis Cockerell through a detailed cladistic study, the fossil 2. Upper gena much narrower than compound groups will likely need to be elevated to trib- eye in lateral view; subantennal sutures al status (as will other generic groups of Os- longer than diameter of antennal sockets miini). (®g. 40); distance between compound eyes equal to or slightly less than length of com- Key to Genera of Osmiini pound eyes; second abscissa Rs orthogonal in Baltic Amber to vein M (®gs. 41, 43) ...... Ctenoplectrella Cockerell 1. Mesepisternum punctate, not areolate; omau- ± Upper gena as broad as compound eye in lat- lar carina absent, omaulus rounded; pro- eral view; subantennal sutures as long as podeum imbricate or smooth, without are- diameter of antennal sockets; distance be- 56 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

tween compound eyes greater than length otum slightly inclined but generally not far of compound eyes; second abscissa of Rs off from horizontal; mesepisternum strongly angulate such that angle between this vein areolate, with precoxal triangle along ante- and M opening toward wing apex is acute rior border of mesocoxa; scrobal suture ab- (®g. 47) ...... Glaesosmia, n. gen. sent; anterior and posterior borders of mete- Genus Glyptapis Cockerell pisternum converging ventrally and meeting one another at point of mesocoxal base; pro- Glyptapis Cockerell, 1909a: 314. Type species: podeum strongly areolate. Claws with strong Glyptapis mirabilis Cockerell, 1909a, monoba- inner tooth, inner tooth shorter than outer; sic [also designated by Cockerell, 1909b]. Cockerell, 1909b: 13. arolium present (®g. 35); outer apex of mesotibia with a very short, broad, apical spine, DIAGNOSIS: This genus can be instantly similar spine on protibial apex, although recognized by the strong areolate sculpturing much shorter than that of mesotibia; two me- of the pleura and propodeum as well as the tatibial spurs, spurs minutely ciliate; metatiba strong and large punctures of the mesoscu- with scattered, elongate, simple setae (®g. tum and scutellum. Furthermore, the long 36). Basal vein strongly arcuate (®g. 37). No cutting edge of the mandible with a single, apparent maculations on integument (color- sharp, lower tooth and the hirsute compound ation is, however, not well preserved in any eyes serve to distinguish Glyptapis species of the known specimens). from not only Baltic amber megachilids but COMMENTS: I had earlier not considered from all other Baltic amber bees. Glyptapis Glyptapis to be a megachilid (Engel, 1999d); can be separated from other genera, living however, having now seen type material of and extinct, placed in the paraphyletic Os- this genus in the Institut und Museum fuÈr miini by the characters presented above for Geologie und PalaÈontologie, I recognize that the subtribe Glyptapina. this genus is, in fact, quite clearly an enig- DESCRIPTION: Mandible with a single, matic lineage of megachilines (as is the ge- small, sharp tooth on lower apical margin nus Ctenoplectrella; see below). The pres- and large upper cutting edge (the mandible ence of a single subantennal suture that is similar in general structure to that of some meets the antennal sockets at their outer mar- anthidiines) (®gs. 30, 32, 33). Malar space gin is known only in Megachilidae and the short, much shorter than basal mandibular absence of basitibial and pygidial plates as width. Clypeus ¯at; extending just below lower tangent of compound eyes (®g. 32). well as possession of only two submarginal Hypostomal ridge carinate, anterior angle cells is indicative of Megachilinae. Although rounded. Compound eyes hirsute, setae long the coarse sculpturing on the pleura is some- (much longer than thrice ommatidial diame- what suggestive of some Old World Anthi- ter) (®g. 32); compound eye broader than diini, as is the presence of a strong omaular gena in lateral view; inner margins straight carina, the apparent absence of integumental and slightly converging below. F1 longer markings, the basal position of 1m-cu rela- than F2; length of F2 approximately equal to tive to the second abscissa of Rs, and the that of F3. Posterior margin of vertex gently relatively long pterostigma excludes Glyp- concave. Preoccipital area sharply angled tapis from that tribe (see also Comments and weakly carinate. Mesoscutum and scu- above under Osmiini). The subtribe Glyptap- tellum coarsely and deeply punctate (®gs. 31, ina (de®ned above) may eventually prove to 38), mesoscutal anterior border broadly represent a lineage more closely allied to the rounded; median line moderately impressed; anthidiines (or from which the anthidiines parapsidal lines faintly impressed and linear arose: i.e., glyptapines may be stem-group (not punctiform); tegula oval; scutellum low, anthidiines), in which case tribal status for weakly convex, not overhanging metanotum, this fossil group would be warranted owing anterior margin with distinct, small, median to its numerous, plesiomorphic osmiine fea- V-shaped notch, smaller lateral notches pre- tures, not too mention its own peculiar apo- sent along anterior margin where scutellum morphies (i.e., sculpturing of mesosoma, laterally bends toward mesoscutum; metan- elongate eye setae). 2001 ENGEL: BALTIC AMBER BEES 57

second. 1m-cu enters second submarginal Key to Species of GLYPTAPIS cell about four times vein width distad of 1. Mesoscutum with punctures approximately second abscissa of Rs; 2rs-m distad 2m-cu one-third ocellar diameter or less and well by two times vein width; second submarginal spaced (not nearly contiguous) (®g. 38); cell gently narrowed anteriorly; 2rs-m gently precoxal triangle bordered anteriorly by curved; cu-a long; inner margin of pterostig- narrow, glabrous margin many times less than width of areolae ...... 2 ma in ®rst submarginal cell longer than width ± Mesoscutum with punctures large, approxi- of pterostigma; inner margin of pterostigma mately one-half ocellar diameter, and in marginal cell gently convex; marginal cell nearly contiguous (®g. 31); precoxal tri- apex acutely rounded, offset from wing mar- angle bordered anteriorly by wide gla- gin by width of vein, not appendiculate. Six brous margin at least 1.5 times width of distal hamuli arranged in a single, evenly areolae ...... G. mirabilis Cockerell spaced series. 2. Precoxal triangle containing distinct trans- Integument generally shining. Mandible verse ridges or striae to form a single, dor- smooth and shining, without outer grooves, soventral row of areolae ...... 3 with faint, small punctures separated by less ± Precoxal triangle without areolae (®g. 33) ...... G. disareolata, n. sp. than a puncture width on basal half. Clypeus 3. Deep, crater-like punctures of scutellum not with small, faint punctures separated by 1±2 restricted to posterior two-thirds; metano- times puncture width, such punctures partic- tum with minute punctures separated by 2± ularly faint on apical third, integument be- 3 times puncture width...... tween punctures smooth. Supraclypeal area ...... G. fuscula Cockerell sculptured as on clypeus. Face with minute ± Deep, crater-like punctures of scutellum re- punctures, more well-de®ned than those of stricted to posterior two-thirds; metanotum clypeus and supraclypeal area, punctures with small punctures densely packed, sep- separated by 1±2 times puncture width, in- arated by puncture width or less ...... tegument between punctures smooth; punc- ...... G. densopunctata, n. sp. tures becoming faint on vertex. Gena with Glyptapis mirabilis Cockerell minute, faint punctures separated by 2±3 Figures 30, 31 times puncture width, integument between Frontispiece and Plate 2e punctures smooth. Postgena smooth and impunctate. Pronotum with very sparse, minute Glyptapis mirabilis Cockerell, 1909a: 314. punctures, also with minute, transverse striae DIAGNOSIS: This species can be separated running along posterior edge of lateral ridge, from all other Glyptapis by the large and integument otherwise smooth. Mesoscutum nearly contiguous punctures of the mesos- strongly punctured; punctures large (ca. 0.5 cutum. Additionally, the precoxal triangle is OD) and deep, separated by less than one- well separated from the areolate sculpturing half a puncture diameter (i.e., nearly contig- of the remainder of the mesepisternum; the uous), integument between such punctures width of the glabrous margin demarcating smooth, with minute punctures separated the anterior border of the precoxal triangle is (where apparent) by three or more times their more than the diameter of the areolae (ap- own diameter (®g. 31). Tegula with minute proximately 1.5 times areolae diameter in punctures separated by two times puncture width). width, integument between smooth. Scutel- DESCRIPTION: Female. Total body length lum sculptured as on mesoscutum. Metano- 5.92 mm; forewing length 4.04 mm. Head tum with large lateral pits, medially with mi- slightly wider than long (length 1.48 mm, nute punctures separated by 2±3 times punc- width 1.56 mm). Upper interorbital distance ture width, integument otherwise smooth. 1.08 mm; lower interorbital distance 0.72 PreeÈpisternal area (here used for anterior-fac- mm. Interocellar distance 0.36 mm; ocello- ing surface of mesepisternum anterior to cular distance 0.28 mm; median to lateral omaular carina: preepisternal suture is ab- ocellus 0.12 mm. Intertegular distance 1.48 sent, as in other long-tongued bees) smooth mm. Basal vein strongly arcuate, con¯uent and impunctate. Mesepisternum coarsely re- with cu-a; ®rst submarginal cell longer than ticulate-areolate, integument inside areolae 58 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 31. Dorsal view of mesosoma of holotype female of Glyptapis mirabilis Cockerell. 2001 ENGEL: BALTIC AMBER BEES 59 smooth; scrobal suture absent (perhaps utter- with a few minute branches. Mesoscutum ly obscured by coarse areolate sculpturing?); with short, plumose setae arising out of precoxal triangle with eight dorsoventral are- large, deep punctures, also with minute, olae (the number of areolae, however, are sparse setae in interspaces between punc- variable; in one other specimen there are tures. Tegula with minute, appressed, simple only four areolae); precoxal triangle anteri- setae not obscuring integument. Scutellum orly separated from remainder of mesepister- with pubescence as on mesoscutum except num by broad glabrous margin that is ap- setae slightly longer. Metanotum with mi- proximately 1.5 times areola diameter in nute, erect, simple setae widely scattered. width. Metepisternum transversely striate, in- PreeÈpisternal area without pubescence; setae tegument between striae smooth. Basal area of mesepisternum (posterior to omaular ca- of propodeum strongly areolate, areolae eas- rina) as on mesoscutum; metepisternum ily 1 OD in diameter, basal area two areolae with scattered, short, simple setae. Basal in length and eight areolae wide, lateral are- area and posterior surface of propodeum olae more rectangular than square areolae without pubescence; lateral surface of pro- near midline; metapostnotum smooth and podeum with pubescence as described for impunctate, bordered by areolae (0.5 OD in metepisternum. Pubescence of legs gener- diameter) that converge ventrally just below ally simple and short except those setae of propodeal pit; outside of areolate borders of tarsi long; inner surface of metafemur with- metapostnotum on posterior propodeal sur- out pubescence, outer, anterior, and poste- face a small glabrous zone of about 1 OD in rior surfaces with short, branched setae; me- width; lateral and ventral borders of posterior tatibia with numerous, somewhat long, setae surface strongly areolate; lateral surface of on all surfaces, most of those on inner sur- propodeum dorsoventrally striate, integu- face simple but a few with minute branches, ment between striae smooth. Metasomal ter- those of outer surface with several short ga and sterna faintly imbricate and impunc- branches. Central discs of metasomal terga tate. with sparse, minute, simple, appressed se- Color not well preserved, apparently en- tae, setae longer and erect to suberect on tirely dark brown without maculations. Wing lateral borders; sterna as for terga except membrane hyaline; veins strong and dark along apical thirds setae longer, erect, sim- brown. ple, and more numerous (to form metasomal Mandible with minute, simple, subappressed scopa). setae, longer on ventral border. Galea with MATERIAL: Three specimens. Holotype. long setae at apex and on inner border near Female, K72 (IMGP) labeled: ``K72, Glyp- apex. Clypeus with minute, appressed, sim- tapis mirabilis n. sp., Geologisch-PalaÈonto- ple setae not obscuring integument, such se- logisches Institut und Museum, GoÈttingen'' tae also on face below level of antennal // ``Holotype, Glyptapis mirabilis Cockerell''. sockets. Widely scattered, longer, erect setae Non-type. Female (CMSE) labeled: on face, clypeus, supraclypeal area; ap- ''Glyptapis mirabilis? Cockerell, det. M. S. pressed, minute setae disappearing by su- Engel''. praclypeal area, replaced on upper face by Non-type. Female, Nr. 33±00524 (CGHG) aforementioned longer, erect setae, although labeled: ``Nr. 33±00524'' // ``Glyptapis mir- now more numerous, such setae long on abilis Cockerell, det. M. S. Engel''. vertex and each bearing a few minute branches. Gena with similar setae as those Glyptapis disareolata, new species of vertex, although shorter, subappressed Figures 32±35 (not obscuring integument), and simple. Plate 2f Postgena with long, erect, widely scattered setae. Pronotum with scattered, minute, sim- DIAGNOSIS: This species is most similar to ple setae, appressed but not obscuring the G. fuscula but differs most notably by the integument except on pronotal lobe where absence of areolae in the precoxal triangle. setae appear dense and short and along dor- DESCRIPTION: Female. Total body length sal carina, with setae short, erect, and each 5.84 mm; forewing length 4.25 mm. Head 60 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

with minute punctures, more well-de®ned than those of clypeus and supraclypeal area, punctures separated by a puncture width, integument between smooth. Gena and postgena with minute punctures separated by a puncture width, integument between smooth. Pronotum with minute punctures separated by a puncture width, also with minute, transverse striae running along posterior edge of lateral ridge, integument between smooth. Mesoscutum strongly punctured; punctures moderately large (ca. 1/3 OD) and deep, separated by less 0.5±2 times puncture width, integument between such punctures smooth with minute punctures separated by 1±2 times their own diameter; anterior border of mesoscutum with deeper puncture closely packed. Tegula with minute punctures separated by a puncture width, integument between smooth. Scutellum sculptured as on mesoscutum except deep punctures restricted Fig. 32. Frontal view of head of holotype fe- to posterior two-thirds. Metanotum with mi- male of Glyptapis disareolata, new species. Scale nute punctures separated by a puncture bar ϭ 1 mm. width, integument between smooth. PreeÈpis- ternal area (here used for anterior-facing sur- slightly wider than long (length 1.63 mm, face of mesepisternum anterior to omaular width 1.91 mm). Upper interorbital distance carina: preepisternal suture is absent, as in 1.22 mm; lower interorbital distance 0.94 other long-tongued bees) with minute punc- mm. Interocellar distance 0.38 mm; ocello- tures separated by a puncture width, integu- cular distance 0.28 mm; median to lateral ment between smooth. Mesepisternum ocellus 0.16 mm. Intertegular distance 1.47 coarsely reticulate-areolate, integument in- mm. Basal vein con¯uent with cu-a; ®rst side areolae smooth; precoxal triangle ante- submarginal cell longer than second; 1m-cu riorly separated from remainder of mesepi- enters second submarginal cell about four sternum by narrow glabrous margin that is times vein width distad of second abscissa of less than 0.5 times areola diameter in width, Rs; 2rs-m distad 2m-cu by two times vein precoxal triangle without areolae (®g. 33). width; second submarginal cell gently nar- Metepisternum transversely striate, integu- rowed anteriorly; 2rs-m gently curved; cu-a ment between striae smooth. Basal area of long; inner margin of pterostigma in ®rst propodeum strongly areolate, areolae easily submarginal cell longer than width of pter- 1 OD in diameter, basal area two areolae in ostigma; inner margin of pterostigma in mar- length and eight areolae wide; metapostno- ginal cell gently convex; marginal cell apex tum smooth and impunctate, bordered by acutely rounded, offset from wing margin by areolae (0.5 OD in diameter) that converge width of vein, not appendiculate; six distal ventrally just below propodeal pit; outside of hamuli, arranged in a single evenly spaced areolate borders of metapostnotum on pos- series (®g. 34). terior propodeal surface a small glabrous Integument generally shining. Mandible zone of about 1 OD in width; lateral and ven- with minute punctures separated by 1±2 tral borders of posterior surface strongly are- times a puncture width, integument between olate; lateral surface of propodeum dorso- smooth. Clypeus with minute punctures sep- ventrally striate, integument between striae arated by 1±2 times puncture width, integu- smooth. Metasomal terga and sterna faintly ment between smooth. Supraclypeal area imbricate. sculptured as on clypeus. Face and vertex Coloration not well preserved; however, 2001 ENGEL: BALTIC AMBER BEES 61

Fig. 33. Right ventrolateral oblique view of head and mesosoma of holotype female of Glyptapis disareolata, new species. where evident, dark brown and without mac- minute, appressed, simple setae not obscur- ulations. Wing membrane hyaline; veins ing integument, such setae also on face be- strong and dark brown. low level of antennal sockets. Widely scat- Mandible with minute, simple, subappressed tered, longer, erect setae on face, clypeus, setae, longer on ventral border. Clypeus with and supraclypeal area; appressed, minute se-

Fig. 34. Hind wing of holotype female of Glyptapis disareolata, new species. Scale bar ϭ 1 mm. 62 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

(posterior to omaular carina) as on mesoscutum; metepisternum with scattered, short, simple setae. Basal area and posterior surface of propodeum without pubescence; lateral surface of propodeum with pubescence as described for metepisternum. Pubescence of legs generally simple and short except those setae of tarsi long; inner surface of metafemur without pubescence, outer, anterior, and posterior surfaces with short, branched setae; metatibia with numerous, somewhat long, setae on all surfaces, most of those on inner surface simple but a few with minute branches, those of outer surface with several, short branches. Central discs of metasomal terga with sparse, minute, simple, appressed setae, setae longer and erect to suberect on lateral borders; sternal scopa composed of dense, long, erect, simple setae. MATERIAL: Two specimens. Holotype. Fe- male, B-JH 104 (AMNH) labeled: ``Baltic amber: Eocene, Kaliningrad, Yantarny'' // ``Holotype, Glyptapis disareolata Engel''. Paratype. Female, B-W 156 (AMNH) la- Figs. 35±36. Leg structures of Glyptapis spe- beled: ``Baltic amber: Eocene, Kaliningrad, cies. 35. Claw and arolium of Glyptapis disareo- Yantarny'' // ``Paratype, Glyptapis disareolata, new species. 36. Metafemur, metatibia, and lata Engel''. metatarsus of female of Glyptapis fuscula Cock- ETYMOLOGY: The speci®c epithet is a com- erell. Scale bars ϭ 0.5 mm (a), 0.25 mm (b); (a ϭ ®g. 36; b ϭ ®g. 35). bination of the Latin words dis (meaning ``without'') and areolatus (meaning ``small spaces'') and is a reference to the absence of tae disappearing by supraclypeal area; face areolae in the precoxal triangle. with longer erect setae intermixed with short, suberect setae; vertex with long, erect setae, Glyptapis densopunctata, new species each bearing a few minute branches. Gena Figure 37 with similar setae as those of vertex, al- Plate 3b though shorter, subappressed (not obscuring integument), and simple. Postgena with long, DIAGNOSIS: This species is most similar to erect, widely scattered setae. Pronotum with G. disareolata; both species have the deep, scattered, minute, simple setae, appressed but crater-like punctures of the scutellum restrict- not obscuring the integument except on pron- ed to the posterior two-thirds and dense otal lobe setae dense and short and along punctures on the metanotum. These charac- dorsal carina setae short, erect, and each with ters serve to separate both G. densopunctata a few minute branches. Mesoscutum with and G. disareolata from G. fuscula. Glyptap- short, plumose setae arising out of large, is densopunctata differs from G. disareolata deep punctures, also with minute, sparse se- by the presence of areolae in the precoxal tae in interspaces between punctures. Tegula triangle. with minute, appressed, simple setae not ob- DESCRIPTION: Female. Total body length scuring integument. Scutellum with pubes- 6.29 mm; forewing length 4.30 mm. Head cence as on mesoscutum except setae slightly slightly wider than long (length 1.72 mm, longer. Metanotum with minute, erect, simple width 1.84 mm). Upper interorbital distance setae widely scattered. PreeÈpisternal area 1.19 mm; lower interorbital distance 0.88 without pubescence; setae of mesepisternum mm. Interocellar distance 0.38 mm; ocello- 2001 ENGEL: BALTIC AMBER BEES 63

times their own diameter; anterior border of mesoscutum with deeper punctures closely packed. Tegula with minute punctures separated by a puncture width, integument between smooth. Scutellum sculptured as on mesoscutum except deep punctures restricted to posterior two-thirds. Metanotum with minute punctures separated by a puncture width or less, integument between (where evident) Fig. 37. Forewing of holotype female of smooth. PreeÈpisternal area (here used for an- Glyptapis densopunctata, new species. Scale bar terior-facing surface of mesepisternum ante- ϭ 1 mm. rior to omaular carina: preepisternal suture is absent, as in other long-tongued bees) with minute punctures separated by a puncture cular distance 0.31 mm; median to lateral width, integument between smooth. Mesepis- ocellus 0.13 mm. Intertegular distance 1.38 ternum coarsely reticulate-areolate, integu- mm. Basal vein con¯uent with cu-a; ®rst ment inside areolae smooth; precoxal triangle submarginal cell longer than second; 1m-cu anteriorly separated from remainder of me- enters second submarginal cell about four sepisternum by narrow glabrous margin that times vein width distad of second abscissa of is less than 0.5 times areola diameter in Rs; 2rs-m distad 2m-cu by two times vein width, precoxal triangle with weak transverse width; second submarginal cell gently nar- striae forming dorsoventral row of areolae. rowed anteriorly; 2rs-m gently curved; cu-a Metepisternum transversely striate, integu- long; inner margin of pterostigma in ®rst ment between striae smooth. Basal area of submarginal cell longer than width of pter- propodeum strongly areolate, areolae 1 OD ostigma; inner margin of pterostigma in mar- or more in diameter, basal area two areolae ginal cell gently convex; marginal cell apex in length and eight areolae wide; lateral sur- acutely rounded, offset from wing margin by face of propodeum dorsoventrally striate, in- width of vein, not appendiculate (®g. 37); tegument between striae smooth. Metasomal eight distal hamuli, arranged in a single, terga and sterna faintly imbricate. evenly spaced series. Color not entirely preserved; however, Integument generally shining. Mandible where evident, dark brown and without mac- with minute punctures separated by 1±2 ulations. Wing membrane hyaline; veins times a puncture width, integument between strong and dark brown. smooth. Clypeus with minute punctures sep- Mandible with minute, simple, subappressed arated by 1±2 times puncture width, integu- setae, longer on ventral border. Clypeus with ment between smooth. Supraclypeal area minute, appressed, simple setae not obscur- sculptured as on clypeus. Face and vertex ing integument, such setae also on face be- with minute punctures, more well-de®ned low level of antennal sockets. Widely scat- than those of clypeus and supraclypeal area, tered, longer, erect setae on face, clypeus, su- punctures separated by a puncture width, in- praclypeal area; appressed, minute setae dis- tegument between smooth. Gena and post- appearing by supraclypeal area; face with gena with minute punctures separated by a longer erect setae intermixed with short, sub- puncture width, integument between smooth. erect setae; vertex with long, erect setae, Pronotum with minute punctures separated each bearing a few minute branches. Gena by a puncture width, also with minute, trans- with similar setae as those of vertex, al- verse striae running along posterior edge of though shorter, subappressed (not obscuring lateral ridge, integument between smooth. integument), and simple. Postgena with long, Mesoscutum strongly punctured; punctures erect, widely scattered setae. Pronotum with moderately large (ca. 1/3 OD) and deep, sep- scattered, minute, simple setae, appressed but arated by less 0.5±2 times puncture width, not obscuring the integument except on pron- integument between such punctures smooth, otal lobe setae dense and short and along with minute punctures separated by 1±2 dorsal carina setae short, erect, and each with 64 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 a few minute branches. Mesoscutum with Glyptapis reducta Cockerell, 1909b: 18. NEW SYN- short, plumose setae arising out of large, ONYMY. deep punctures, also with minute, sparse se- Glyptapis neglecta Salt, 1931: 136. NEW SYNONY- tae in interspaces between punctures. Tegula MY. with minute, appressed, simple setae not ob- Dasypoda sp. Gerlach, 1989: 253. [misidenti®ca- scuring integument. Scutellum with pubes- tion; ϭ G. reducta Cockerell] cence as on mesoscutum except setae slightly DIAGNOSIS: This species is similar to G. longer. Metanotum with minute, erect, simple densopunctata and G. disareolata but has the setae widely scattered. PreeÈpisternal area deep, crater-like punctures not restricted to without pubescence; setae of mesepisternum the posterior two-thirds of the scutellum and (posterior to omaular carina) as on mesos- the punctures of the metanotum more widely cutum; metepisternum with scattered, short, spaced. simple setae. Basal area and posterior surface DESCRIPTION: Female. Total body length of propodeum without pubescence; lateral 7.04 mm; forewing length 4.32 mm. Head surface of propodeum with pubescence as slightly wider than long (length 1.76 mm, described for metepisternum. Pubescence of width 1.80 mm). Upper interorbital distance legs generally simple and short except those 1.20 mm; lower interorbital distance 0.84 setae on tarsi long; inner surface of metafe- mm. Interocellar distance 0.40 mm; ocello- mur without pubescence, outer, anterior, and cular distance 0.28 mm; median to lateral posterior surfaces with short, branched setae; ocellus 0.16 mm. Intertegular distance 1.64 metatibia with numerous, somewhat long setae on all surfaces, most of those on inner mm. Basal vein con¯uent with cu-a; ®rst surface simple but a few with minute branch- submarginal cell longer than second; 1m-cu es, those of outer surface with several short enters second submarginal cell about eight branches. Central discs of metasomal terga times vein width distad second abscissa of with sparse, minute, simple, appressed setae, Rs; 2rs-m distad 2m-cu by vein width; sec- setae longer and erect to suberect on lateral ond submarginal cell gently narrowed ante- borders; sternal scopa composed of dense, riorly; 2rs-m gently curved; inner margin of long, erect, simple setae. pterostigma in ®rst submarginal cell longer MATERIAL: Four specimens. Holotype. Fe- than width of pterostigma; inner margin of male, B-W 161 (AMNH) labeled: ``Baltic pterostigma in marginal cell gently convex; amber: Eocene, Kaliningrad, Yantarny'' // marginal cell apex acutely rounded, offset ``Holotype, Glyptapis densopunctata Engel''. from wing margin by width of vein, not ap- Paratype. Female, B-JH 89 (AMNH) la- pendiculate; six distal hamuli, arranged in a beled: ``Baltic amber: Eocene, Kaliningrad, single, evenly spaced series. Yantarny'' // ``Paratype, Glyptapis denso- Integument generally shining. Mandible punctata Engel''. with minute punctures separated by 1±2 Paratype. Female, Nr. 2623 (CCGG) la- times a puncture width, integument between beled: ``Nr. 2623'' // ``Paratype, Glyptapis smooth. Clypeus with minute punctures sep- densopunctata Engel''. arated by 1±2 times puncture width, integu- Paratype. Female, Nr. 857 (CHFG) la- ment between smooth. Supraclypeal area beled: ``Nr. 857, Balt. Bernstein'' // ``Para- sculptured as on clypeus. Face and vertex type, Glyptapis densopunctata Engel''. with minute punctures, more well-de®ned ETYMOLOGY: The speci®c epithet is a com- than those of clypeus and supraclypeal area, bination of the Latin words densus (meaning punctures separated by a puncture width, in- ``dense'') and punctatum (meaning ``punc- tegument between smooth. Gena and post- tures'') and is a reference to the dense punc- gena with minute punctures separated by a tures of the metanotum. puncture width, integument between smooth. Glyptapis fuscula Cockerell Pronotum with minute punctures separated Figures 36, 38, 39 by a puncture width, also with minute, trans- Plate 3a verse striae running along posterior edge of Glyptapis fuscula Cockerell, 1909b: 17. lateral ridge, integument between smooth. Glyptapis reticulata Cockerell, 1909b: 16. NEW Mesoscutum strongly punctured; punctures SYNONYMY. moderately large (ca. 1/3 OD) and deep, sep- 2001 ENGEL: BALTIC AMBER BEES 65

Fig. 38. Dorsolateral view of mesosoma of holotype female of Glyptapis fuscula Cockerell. arated by less 0.5±2 times puncture width, is less than one-half times areola diameter in integument between such punctures smooth, width, precoxal triangle without strong are- with minute punctures separated by 1±2 olae, instead with weak longitudinal striae times their own diameter; anterior border of that extend only one-half of precoxal trian- mesoscutum with deeper puncture closely gle. Metepisternum transversely striate, in- packed (®g. 38). Tegula with minute punc- tegument between striae smooth. Basal area tures separated by a puncture width, integu- of propodeum strongly areolate, areolae eas- ment between smooth. Scutellum sculptured ily 1 OD in diameter, basal area two areolae as on mesoscutum, deep, crater-like punc- in length and eight areolae wide; metapost- tures on all parts of scutellum (not restricted notum smooth and impunctate, bordered by to posterior two-thirds). Metanotum with mi- areolae (0.5 OD in diameter) that converge nute punctures separated by 2±3 times punc- ventrally just below propodeal pit; small gla- ture width, integument between smooth. brous zone of about 1 OD in width appearing PreeÈpisternal area (here used for anterior-fac- outside of areolate borders of metapostnotum ing surface of mesepisternum anterior to on posterior propodeal surface; lateral and omaular carina: preepisternal suture is ab- ventral borders of posterior surface strongly sent, as in other long-tongued bees) with mi- areolate; lateral surface of propodeum dor- nute punctures separated by a puncture soventrally striate, integument between striae width, integument between smooth. Mesepis- smooth. Metasomal terga and sterna faintly ternum coarsely reticulate-areolate, integu- imbricate. ment inside areolae smooth; precoxal triangle Color dark brown without maculations. anteriorly separated from remainder of me- Wing membrane hyaline; veins dark brown. sepisternum by narrow glabrous margin that Mandible with minute, simple, subappressed 66 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 39. Lateral view (posterior portion of head in lower right-hand corner) of mesosoma of holotype female of Glyptapis fuscula Cockerell. Mesepisternum sculpturing in focus; precoxal triangle cannot be seen in this image. setae, longer on ventral border. Clypeus with minute, sparse setae in interspaces between minute, appressed, simple setae not obscur- punctures. Tegula with minute, appressed, ing integument, such setae also on face be- simple setae not obscuring integument. Scu- low level of antennal sockets. Widely scat- tellum with pubescence as on mesoscutum tered, longer, erect setae on face, clypeus, su- except setae slightly longer. Metanotum with praclypeal area; appressed, minute setae dis- minute, erect, simple setae widely scattered appearing by supraclypeal area, replaced on and a medial patch of long, erect setae, each upper face by aforementioned longer, erect with a few minute branches. PreeÈpisternal setae although now more numerous, such se- area without pubescence; setae of mesepis- tae long on vertex and each bearing a few ternum (posterior to omaular carina) as on minute branches. Gena with similar setae as mesoscutum; metepisternum with scattered, those of vertex although shorter, subappressed short, simple setae. Basal area and posterior (not obscuring integument), and simple. surface of propodeum without pubescence; Postgena with long, erect, widely scattered lateral surface of propodeum with pubes- setae. Pronotum with scattered, minute, sim- cence as described for metepisternum. Pu- ple setae, appressed but not obscuring the in- bescence of legs generally simple and short tegument except on pronotal lobe setae dense except those setae on tarsi long; inner surface and short and along dorsal carina setae short, of metafemur without pubescence, outer, an- erect, and each with a few minute branches. terior, and posterior surfaces with short, Mesoscutum with short, plumose setae aris- branched setae; metatibia with numerous, ing out of large, deep punctures, also with somewhat long, setae on all surfaces, most 2001 ENGEL: BALTIC AMBER BEES 67 of those on inner surface simple but a few MB.I.1936 (No. 18) // ``18'' // ``Glyptapis with minute branches, those of outer surface fuscula Cockerell, det. M. S. Engel, 1999''. with several, short branches. Central discs of Non-type. Female, MB.I.1937 (ZMHB) metasomal terga with sparse, minute, simple, labeled: ``Museum fuÈr Naturkunde Berlin, appressed setae, setae longer and erect to PalaÈontologisches Museum, Inv. Nr. suberect on lateral borders; sternal scopa MB.I.1937, Slg. Berendt'' // ``Glyptapis composed of dense, long, erect, simple setae. fuscula Cockerell, det. M. S. Engel''. MATERIAL: Nine specimens. Holotype Non-type. Female, Nr. 1015 (CHMG) la- (fuscula). Female, K66 (IMGP) labeled: beled: ``Nr. 1015'' // ``Glyptapis fuscula ``Holotype, Glyptapis fuscula Cockerell'' // Cockerell, det. M. S. Engel''. ``Holotype, K66, Glyptapis fuscula n. sp. Non-type. Female (CFEG) labeled: Cockerell, Geologisch-PalaÈontologisches In- ``Glyptapis fuscula Cockerell, det. M. S. En- stitut und Museum, GoÈttingen`` // ``Glyptapis gel''. fuscula'' // ``Glyptapis fuscula Cock. COMMENTS: Salt's description of G. neg- [ϭCockerell], K66''. lecta agrees with G. fuscula in every respect, Neotype (reticulata; here designated). particularly the sculpturing of the mesoscu- Female, B-JH 78 (AMNH) labeled: ``Baltic amber: Eocene, Kaliningrad, Yantarny'' // tum. Salt considered the distinguishing fea- ``Neotype, Glyptapis reticulata Cockerell'' // ture between his specimen and G. fuscula to ``Glyptapis fuscula Cockerell, det. M. S. En- be the hyaline wing membrane in his species; gel''. however, the surviving holotype of G. fus- Holotype (reducta). Female, G4668 cula does not actually have fuscous wing (IMGP) labeled: ``Holotype, Glyptapis re- membranes. I therefore consider G. neglecta ducta Cockerell'' // Holotype, G4668, Glyp- and G. fuscula to be conspeci®c. The holo- tapis reducta n. sp. Cockerell'' // Reservierte type of G. neglecta, however, has since be- Registiernummer, Dasypoda: G4668 [Ger- come lost (it was originally in the ill-fated lach handwriting]`` // ``Dasypoda sp. indet., KoÈnigsberg collection). I, therefore, here Gerlach, J., 1987'' // ``Glytapis fuscula designate a neotype of a specimen from the Cockerell, det. M. S. Engel''. The eye setae AMNH collection which agrees with Salt's are dif®cult to see but present. The coarse description. Acting as ®rst reviser (ICZN, sculpturing, although also dif®cult to view 1999b: Art. 24.2) I have chosen G. fuscula through the ®ne layer of Schimmel on the as the valid name for this taxon and consider specimen, can be seen. G. reducta and G. reticulata, both published Neotype (neglecta; here designated). Fe- in the same article, to be junior synonyms. male B-JH 78 (AMNH) labeled: ``Neotype, Gerlach (1989) misidenti®ed the holotype Glyptapis neglecta Salt, desig. M. S. Engel'' of G. reducta as a species of the melittid ge- // ``Glyptapis fuscula Cockerell, det. M. S. nus Dasypoda (Melittidae: Dasypodainae). Engel'' (see Comments below). This is the There is a thin layer of mold over most of same specimen designated as the neotype of the specimen but the punctures of the me- G. reticulata and thus all other labels are sosoma can be easily seen through and with- identical with those listed above. in gaps of the mold. There is absolutely no Non-type. Female (ZMUC) labeled: resemblance between G. reducta (nor any ``Apoidea, A. Henningsen, 9±9, 1974'' // Glyptapis for that matter) and species of Da- ``Glyptapis fuscula Cockerell, det. M. S. En- sypoda. gel''. This is the specimen ®gured by Poinar (1994: 75). Non-type. Female, B-W 155 (AMNH) la- Glyptapis sp. indet. beled: ``Baltic amber: Eocene, Kaliningrad, Yantarny'' // ``Glyptapis fuscula? Cockerell, MATERIAL: One specimen. Non-type. Fe- det. M. S. Engel''. male, MB.I.1944 (ZMHB) labeled: ``Muse- Non-type. Female, MB.I.1936 (ZMHB) um fuÈr Naturkunde Berlin, PalaÈontologisches labeled: ``Museum fuÈr Naturkunde Berlin, Museum, Inv. Nr. MB.I.1944'' // ``Glyptapis PalaÈontologisches Museum, Inv. Nr. sp. indet., det. M. S. Engel''. 68 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Glyptapis sp. indet. MATERIAL: One specimen. Non-type. Fe- male, Nr. 577/1 (CHFG) labeled: ``Nr. 577/ 1, Bittf. [Bitterfeld] Bernstein'' // ``Glyptapis sp. indet., det. M. S. Engel''.

Genus Ctenoplectrella Cockerell Ctenoplectrella Cockerell, 1909a: 314. Type species: Ctenoplectrella viridiceps Cockerell, 1909a, monobasic. Cockerell, 1909b: 19. Zeu- ner and Manning, 1976: 172.

DIAGNOSIS: Among Baltic amber Megach- linae Ctenoplectrella is most similar to Glae- sosmia but differs by the longer supraclypeal area, narrow gena, and more orthogonal second abscissa of Rs. DESCRIPTION: Mandible with three teeth along apical margin, upper tooth separated from lower two teeth by a short, gently concave cutting-edge (®g. 40). Malar space short, much shorter than basal mandibular Fig. 40. Frontal view of head of neotype fe- width. Clypeus ¯at; not extending below male of Ctenoplectrella viridiceps Cockerell. lower tangent of compound eyes (®g. 40). Scale bar ϭ 1 mm. Hypostomal ridge carinate, anterior angle rounded. Subantennal sutures longer than antennal socket diameter. Compound eyes bare sociated with the apine genera Ctenoplectra (®g. 40); compound eye broader than gena Kirby (In Kirby and Spence, 1826) and Cten- in lateral view; inner margins straight and oplectrina Cockerell (1930b), together form- slightly converging below. F1 slightly longer ing the tribe Ctenoplectrini. Oddly, the unity than F2; length of F2 approximately equal to of Ctenoplectrella with Ctenoplectrini seems that of F3. Posterior margin of vertex gently to be simply based upon two entirely un- concave. Preoccipital area rounded. Mesos- founded criteria, 1. the name chosen by cutum and scutellum not coarsely sculptured; Cockerell (1909a), which suggests some af- mesoscutal anterior border broadly rounded ®nity between the groups (Ctenoplectrella is (®g. 45); median line moderately impressed; a diminutive form of Ctenoplectra); and 2. parapsidal lines faintly impressed and linear; an anecdotal comment by Cockerell (1909b) tegula oval; scutellum low, weakly convex, who said (p. 13), ``Their [Glyptapis and not overhanging metanotum, anterior margin Ctenoplectrella] nearest relative in the mod- without notches; metanotum slightly inclined ern fauna appears to be Ctenoplectra...,'' but but generally not far off from horizontal (®g. provided no characters to support such a re- 46); anterior and posterior borders of mete- lationship. Indeed, the wing venation of pisternum converging ventrally and meeting Ctenoplectrella shares a super®cial similarity one another at point of mesocoxal base; pro- to that of some Ctenoplectrini. Unfortunate- podeum not strongly sculptured. Claws with ly, the similarity between the two groups inner tooth, inner tooth shorter than outer ends at this point (detailed above and further (®g. 42); arolium present (®g. 42); outer apex below). The Ctenoplectrini was originally of mesotibia without spine; two metatibial proposed as a family by Cockerell (1930a), spurs, spurs serrate. Basal vein strongly ar- later moved into the Melittidae as a subfam- cuate; second abscissa Rs approximately or- ily (Michener, 1944), resurrected as a family thogonal to M (®gs. 41, 43). No apparent intermediate between short- and long- maculations on integument. tongued bees by Michener and Greenberg COMMENTS: This genus has long been as- (1980), only to be later recognized as a de- 2001 ENGEL: BALTIC AMBER BEES 69 rived group of Apinae where it is currently dible that is reminiscent of the Megachilinae, placed (Roig-Alsina and Michener, 1993; the presence of a true metasomal scopa, the Michener, 2000a). The placement of Cteno- strongly arcuate basal vein, the absence of plectrella has generally followed that of hairs on the metapostnotum, and the absence Ctenoplectra (e.g., Zeuner and Manning, of a metabasitibial plate, among numerous 1976; Michener and Greenberg, 1980), once other characters. again, presumably owing to the common der- The absence of a preepisternal groove, the ivation of their names and Cockerell's com- shortened jugal lobe, and the fully exposed ment rather than any shared characteristics. mesocoxa are all characteristic of Melittidae Zeuner and Manning (1976) followed Cock- ϩ long-tongued bees, while most Apidae erell's assertion of af®nity with Ctenoplectra have the lateral portions of the clypeus and placed Ctenoplectrella and Glyptapis in strongly bent posteriorly, a feature absent in Ctenoplectrinae, at that time in the Melittidae Megachilidae and Melittidae (as well as (sensu Michener, 1944). It is, unfortunately, Ctenoplectrella and Glyptapis; unobservable apparent that neither of these authors had ac- for Glaesosmia). Among the Megachilinae, tually seen specimens of the latter two gen- however, Ctenoplectrella is remarkable for era. For instance, Zeuner and Manning (op. the slanting metanotum and the broad labrum cit.) characterize these groups as having the (the latter plesiomorphic trait shared with inner metatibial spur modi®ed as in Cteno- Glyptapis). plectra; namely, broadened basally with numerous, elongate teeth, as well as having a Key to Species of CTENOPLECTRELLA pygidial plate in females. Although the ho- 1. Crossvein 2rs-m strongly and doubly arcuate, lotype for Ctenoplectrella is lost (a neotype thus second submarginal cell more strongly is designated below), the types of Glyptapis produced toward wing apex along its pos- have survived in the Institut und Museum fuÈr terior margin (®g. 43); medioapical margin Geologie und PalaÈontologie, GoÈttingen and of clypeus straight ...... 2 none of these characters are present in Glyp- ± Crossvein 2rs-m relatively straight and there- tapis (nor in the neotype of Ctenoplectrella). fore second submarginal cell not more Moreover, these distinctive characters are strongly produced toward wing apex along never once mentioned by Cockerell (1909b) its posterior margin (®g. 41); medioapical who was quite adept and would undoubtedly margin of clypeus gently convex (®g. 40) have noticed these peculiar features. Zeuner ...... C. viridiceps Cockerell 2. Mesoscutum and scutellum punctate .... and Manning (1976) do not provide descrip- ...... C. cockerelli, n. sp. tions for these taxa, instead referring to the ± Mesoscutum and scutellum impunctate . . original works, once again suggesting that ...... C. grimaldii, n. sp. Zeuner and Manning did not have the op- portunity to see specimens of these taxa be- Ctenoplectrella viridiceps Cockerell fore their untimely deaths. The type of Cten- Figures 40±42 oplectrella viridiceps was certainly not avail- Plate 3c±e able to Zeuner and Manning since it was lost during World War II. The specimen here con- Ctenoplectrella viridiceps Cockerell, 1909a: 314. sidered as the neotype for Ctenoplectrella Ctenoplectrella dentata Salt, 1931: 139. NEW SYN- agrees in every respect with Cockerell's de- ONYMY. scription and, of particular importance, with Ctenoplectrella splendens Kelner-Pillault, 1970a: 13. NEW SYNONYMY. his ®gures (especially in the shape of the pterostigma, which is quite distinctive). I am DIAGNOSIS: This species is distinguished therefore con®dent that the Ctenoplectrella by the gently concave mediapical margin of of Cockerell is the same as my own. the clypeus (®g. 40) and weakly arcuate 2rs- Ctenoplectrella differs from Ctenoplectrini m (®g. 41). (Apidae) by the ¯at clypeus (not bent pos- DESCRIPTION: Female. Total body length teriorly at the apicolateral margins), the 5.85 mm; forewing length 3.06 mm. Head coarsely serrate inner metatibial spur, the ab- slightly wider than long (length 1.53 mm, sence of a pygidial plate, the broadened man- width 1.88 mm). Upper interorbital distance 70 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 41. Forewing of neotype female of Cten- Fig. 42. Claw and arolium of neotype female oplectrella viridiceps Cockerell. Scale bar ϭ 1 of Ctenoplectrella viridiceps Cockerell. Scale bar mm. ϭ 0.25 mm.

1.16 mm; lower interorbital distance 1.00 slightly faint punctures separated by 1±2 mm. Interocellar distance 0.44 mm; ocello- times a puncture width, integument between cular distance 0.33 mm; median ocellus to smooth, punctures becoming somewhat lateral ocellus 0.16 mm. Median and parap- fainter ventrally and posteriorly. Metepister- sidal lines moderately impressed, parapsidal num impunctate and smooth. Propodeum lines elongate (not punctiform). Intertegular (basal, lateral, and posterior surfaces) ®nely distance 1.31 mm. Basal vein con¯uent with imbricate. Terga with minute, faint punctures cu-a; second abscissa Rs basad 1m-cu by 6.5 separated by 1±3 times a puncture width, in- times vein width; 2rs-m distad 2m-cu by two tegument between ®nely imbricate; sterna times vein width, 2rs-m relatively straight, imbricate. arching only toward its apex before meeting Coloration dark brown without macula- vein M; second submarginal cell slightly lon- tions. Wing membrane hyaline except be- ger than ®rst submarginal cell; six distal tween C and ScϩR slightly fuscous in some hamuli arranged in a single, evenly spaced specimens; veins strong and dark brown. series. Mandible with minute, simple, appressed Outer surface of mandible with minute setae. Clypeus with minute, appressed, sim- punctures separated by a puncture width or ple setae not obscuring integument; similar less, integument between smooth. Clypeus setae also on face below level of antennal with faint, coarse punctures separated by a sockets, intermixed with scattered, longer, puncture width or less, integument between erect setae on face, clypeus, supraclypeal smooth. Supraclypeal area and face with area, gena, and postgena. Mesoscutum and punctures more well-de®ned than those of scutellum with scattered, short, simple setae clypeus and separated by 1±2 times puncture except those of scutellum slightly longer. width, integument between smooth. Vertex Pleural pubescence as described for mesos- and gena with sculpturing as on face al- cutum. Basal area of propodeum without pu- though punctures slightly more closely bescence; lateral and posterior surfaces with spaced, separated by about a puncture width, pubescence as described for mesoscutum. integument between smooth. Mesoscutum Pubescence of legs generally simple and with small punctures separated by a puncture short; inner surface of metafemur without width or slightly less, integument between pubescence, outer, anterior, and posterior sur- smooth. Tegula with minute punctures sepa- faces with short, branched setae; metatibia rated by 1±2 times a puncture width, integ- with scattered, simple, moderate-length se- ument between smooth. Scutellum sculptured tae, a few with minute branches. Central as on mesoscutum. Metanotum impunctate discs of metasomal terga with sparse, minute, and smooth. PreeÈpisternal area (i.e., anterior- simple, appressed setae, setae longer and facing surface anterior to omaulus) essential- erect to suberect on lateral borders; sternal ly impunctate and smooth except for a few, scopa composed of dense, long, erect, simple exceedingly faint, widely spaced, coarse setae. punctures. Mesepisternum with coarse, Male. As described for the female except 2001 ENGEL: BALTIC AMBER BEES 71 as indicated: Total body length 6.93 mm; labeled: ``Museum fuÈr Naturkunde Berlin, forewing length 4.00 mm. Head slightly wid- PalaÈontologisches Museum, Inv. Nr. er than long (length 1.70 mm, width 1.86 MB.I.1941 (No. 17)'' // ``17'' // ``Ctenoplec- mm). Upper interorbital distance 1.10 mm; trella viridiceps Cockerell, det. M. S. En- lower interorbital distance 1.00 mm. Intero- gel''. cellar distance 0.40 mm; ocellocular distance Non-type. Female, Nr. 24 (CFKG) la- 0.31 mm; median ocellus to lateral ocellus beled: ``1987, Nr. 24'' // ``Ctenoplectrella 0.17 mm. Intertegular distance 1.45 mm. Fla- viridiceps Cockerell, det. M. S. Engel''. gellum elongate, reaching to posterior mar- Non-type. Female (CJVG) labeled: gin of mesoscutum; F1 longer than F2; F2 ``Ctenoplectrella viridiceps Cockerell, det. equal in length to F3. T6 deeply bi®d at apex M. S. Engel''. and slightly protuberant. Metasomal scopa Non-type. Female, Nr. 1615 (CCGG) la- absent. beled: ``Nr. 1615'' // ``Ctenoplectrella viri- MATERIAL: Ten specimens. Neotype (viridiceps Cockerell, det. M. S. Engel''. diceps; here designated). Female, B-JH 95 COMMENTS: The species was proposed as (AMNH) labeled: ``Baltic amber: Eocene, new again by Cockerell (1909b) but the Kaliningrad, Yantarny'' // ``Neotype, Cteno- name was already made available by Cock- plectrella viridiceps Cockerell, desig. M. S. erell (1909a). Engel''. The specimen here designated as the neo- Neotype (dentata; here designated). type agrees with Cockerell's original descrip- Male, NB.I.1949 (ZMHB) labeled: ``Neo- tion and ®gures, particularly in the shape of type, Ctenoplectrella dentata Salt, desig. M. the pterostigma. Zeuner and Manning (1976) S. Engel''. This is the same as specimen as indicate the holotype to have been moved to the holotype for C. splendens and therefore the Museum fuÈr Naturkunde, Humboldt- the remaining labels of the specimen are giv- UniversitaÈt, Berlin, but upon inspection of en below under C. splendens. their collection I failed to ®nd any specimens Holotype (splendens). Male, NB.I.1949 from the KoÈnigsberg collection. Most mate- (ZMHB) labeled: ``49'' // ``Ctenoplectrella rial from the former KoÈnigsberg collection splendens, Holotype, S. Kelner-Pillault det.'' eventually ended up in the Institut und Mu- // ``Holotyp [sic], PalaÈontologisches Museum seum fuÈr Geologie und PalaÈontologie, GoÈt- Berlin, Ctenoplectrella splendens Kelner-Pil- tingen, where some of Cockerell's other lault, 1970, Baltischer Bernstein'' // ``Holo- type, Ctenoplectrella splendens Kelner-Pil- types were discovered (e.g., those of Glyp- lault''. tapis), but Ctenoplectrella was not among Non-type. Female, B-JH 93 (AMNH) la- them. Ctenoplectrella was cataloged in the beled: ``Baltic amber: Eocene, Kaliningrad, GoÈttingen collection as specimen ``K65'' but Yantarny'' // ``Ctenoplectrella viridiceps it was not to be found. I therefore consider Cockerell, det. M. S. Engel''. the holotype to have been lost and here des- Non-type. Female, B-JH 83 (AMNH) la- ignate a neotype. beled: ``Baltic amber: Eocene, Kaliningrad, The species proposed by Salt (1931), a Yantarny'' // ``Ctenoplectrella viridiceps male of Ctenoplectrella, is undoubtedly the Cockerell, det. M. S. Engel''. male for C. viridiceps. The neotype of C. Non-type. Female, B-W 158 (AMNH) la- splendens in Berlin is the only existing male beled: ``Baltic amber: Eocene, Kaliningrad, specimen (of any genus!) preserved in Baltic Yantarny'' // ``Ctenoplectrella viridiceps? amber. Cockerell, det. M. S. Engel''. Non-type. Female, MB.I.1940 (ZMHB) Ctenoplectrella cockerelli, new species labeled: ``Museum fuÈr Naturkunde Berlin, Figures 43, 44 PalaÈontologisches Museum, Inv. Nr. MB.I.1940 (No. 29)'' // ``29'' // ``Cteno- DIAGNOSIS: This is most similar to C. gri- plectrella viridiceps Cockerell, det. M. S. maldii (see below) in the strongly produced Engel''. second submarginal cell (®g. 43), straight Non-type. Female, MB.I.1941 (ZMHB) clypeal apex, and narrow gena but differs by 72 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 43±44. Wings of holotype female of Ctenoplectrella cockerelli, new species. 43. Forewing. 44. Hind wing. Scale bar ϭ 1 mm. the presence of punctures on the mesoscutum less, integument between smooth. Clypeus and scutellum (absent in C. grimaldii). with small punctures separated by a puncture DESCRIPTION: Female. Total body length width or less, integument between smooth. 5.35 mm; forewing length 3.65 mm. Head Supraclypeal area sculptured as on clypeus. slightly wider than long (length 1.56 mm, Face with punctures separated by 1±1.5 times width 1.78 mm). Upper interorbital distance a puncture width, integument between 1.13 mm; lower interorbital distance 0.97 smooth. Vertex and gena with small punc- mm. Interocellar distance 0.31 mm; ocello- tures separated by about a puncture width, cular distance 0.31 mm; median ocellus to integument between smooth. Mesoscutum lateral ocellus 0.13 mm. Intertegular distance with small punctures separated by a puncture 1.28 mm. Basal vein con¯uent with cu-a; width or slightly less, integument between second abscissa of Rs basad 1m-cu by seven smooth. Tegula with minute punctures sepa- times vein width; 2rs-m distad 2m-cu by vein rated by a puncture width, integument be- width, 2rs-m doubly arcuate; second sub- tween smooth. Scutellum sculptured as on marginal cell slightly longer than ®rst sub- mesoscutum. Metanotum impunctate and marginal cell; eight distal hamuli, arranged smooth. PreeÈpisternal area (i.e., anterior-fac- in a single, evenly spaced series (®g. 44). ing surface anterior to omaulus) essentially Outer surface of mandible with minute impunctate and smooth except for a few, ex- punctures separated by a puncture width or ceedingly faint, widely spaced, coarse punc- 2001 ENGEL: BALTIC AMBER BEES 73 tures. Mesepisternum with coarse, slightly ®rst to critically examine the Baltic amber faint punctures separated by a puncture bees and to attempt to place them into a phy- width, integument between smooth, punc- logenetic context. Weber (1965, 2000) has tures becoming somewhat fainter ventrally presented a bibliography of Cockerell's pa- and posteriorly. Metepisternum impunctate pers as well as a sampling of his published and smooth. Propodeum (basal, lateral, and writings on topics ranging from entomology posterior surfaces) impunctate and smooth. to philosophy. Terga with small punctures separated by 1± 2 times a puncture width, integument be- Ctenoplectrella grimaldii, new species tween smooth; sterna imbricate. Figures 45, 46 Color brown without maculations. Wing Plate 3f membrane hyaline; veins strong and dark brown. DIAGNOSIS: Refer to diagnosis presented Mandible with minute, simple, appressed for C. cockerelli (above). setae. Clypeus with minute, appressed, sim- DESCRIPTION: Female. Total body length ple setae not obscuring integument; similar 5.40 mm; forewing length 3.56 mm. Head setae also on face below level of antennal slightly wider than long (length 1.34 mm, sockets, intermixed with scattered, longer, width 1.72 mm). Upper interorbital distance erect setae on face, clypeus, supraclypeal 1.11 mm; lower interorbital distance 1.00 area, gena, and postgena. Mesoscutum and mm. Interocellar distance 0.34 mm; ocello- scutellum with scattered, short, simple setae cular distance 0.31 mm; median ocellus to except those of scutellum slightly longer. lateral ocellus 0.16 mm. Intertegular distance Pleural pubescence as described for mesos- 1.13 mm. Basal vein con¯uent with cu-a; cutum. Basal area of propodeum without pu- second abscissa of Rs basad 1m-cu by seven bescence; lateral and posterior surfaces with times vein width; 2rs-m distad 2m-cu by vein pubescence as described for mesoscutum. width, 2rs-m doubly arcuate; second sub- Pubescence of legs generally simple and marginal cell slightly longer than ®rst sub- short; inner surface of metafemur without marginal cell; eight distal hamuli, arranged pubescence, outer, anterior, and posterior sur- in a single, evenly spaced series. faces with short, branched setae; metatibia Mandibular sculpturing not visible. Clyp- with scattered, simple, moderate-length se- eus with small punctures separated by a tae, a few with minute branches. Central puncture width or less, integument between discs of metasomal terga with sparse, minute, smooth. Supraclypeal area sculptured as on simple, appressed setae, setae longer and clypeus. Face with punctures separated by 1± erect to suberect on lateral borders; sternal 1.5 times a puncture width, integument be- scopa composed of bands of dense, long, tween smooth. Vertex and gena with small erect, simple setae. punctures separated by about a puncture MATERIAL: Three specimens. Holotype. width, integument between smooth. Mesos- Female, B-W 160 (AMNH) labeled: ``Baltic cutum, scutellum, and metanotum impunc- amber: Eocene, Kaliningrad, Yantarny'' // tate and ®nely imbricate. Tegula with minute, ``Holotype, Ctenoplectrella cockerelli En- faint punctures separated by 1±2 times a gel''. puncture width, integument between faintly Paratype. Female, MB.I.1942 (ZMHB) imbricate. Pleura impunctate and ®nely im- labeled: ``Museum fuÈr Naturkunde Berlin, bricate. Propodeum impunctate and imbri- PalaÈontologisches Museum, Inv. Nr. cate. Terga and sterna imbricate. MB.I.1942 (No. 31)'' // ``31'' // ``Paratype, Color dark brown or black without mac- Ctenoplectrella cockerelli Engel''. ulations. Wing membrane hyaline; veins Paratype. Female, Nr. 1011 (CCGG) la- strong and dark brown. beled: ``Nr. 1011'' // ``Paratype, Ctenoplec- Mandible with minute, simple, appressed trella cockerelli Engel''. setae. Clypeus with minute, appressed, sim- ETYMOLOGY: The speci®c epithet is a pat- ple setae not obscuring integument; similar ronymic honoring the late Prof. Theodore D. setae also on face below level of antennal A. Cockerell (1866±1948). Cockerell was the sockets, intermixed with scattered, longer, 74 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 45±46. Holotype female of Ctenoplectrella grimaldii, new species. 45. Dorsal view of holotype. 46. Left lateral view of mesosomal dorsum. Scale bar ϭ 1 mm. erect setae on face, clypeus, supraclypeal scopa composed of dense, long, erect, simple area, gena, and postgena. Mesoscutum and setae. scutellum with scattered, short, simple setae MATERIAL: One specimen. Holotype. Fe- except those of scutellum slightly longer. male, B-JH 88 (AMNH) labeled: ``Baltic am- Pleural pubescence as described for mesos- ber: Eocene, Kaliningrad, Yantarny'' // ``Ho- cutum. Basal area of propodeum without pu- lotype, Ctenoplectrella grimaldii Engel''. bescence; lateral and posterior surfaces with ETYMOLOGY: The speci®c epithet is a pat- pubescence as described for mesoscutum. ronymic honoring Dr. David A. Grimaldi for Pubescence of legs generally simple and his friendship, advice, and assistance with short; inner surface of metafemur without my paleontological studies. pubescence, outer, anterior, and posterior surfaces with short, branched setae; metatibia Ctenoplectrella sp. indet. with scattered, simple, moderate-length se- MATERIAL: One specimen. Non-type. Fe- tae, a few with minute branches. Central male, Nr. 1616 (CCGG) labeled: ``Nr. 1616'' discs of metasomal terga with sparse, minute, // ``Ctenoplectrella sp. indet., det. M. S. En- simple, appressed setae, setae longer and gel''. erect to suberect on lateral borders; sternal COMMENTS: It is possible that this speci- 2001 ENGEL: BALTIC AMBER BEES 75 men represents another individual of C. viridiceps.

Ctenoplectrella sp. indet. MATERIAL: One specimen. Non-type. Fe- male, Nr. 3000 (GPUH) labeled: ``Nr. 3000'' // ``Ctenoplectrella sp. indet., det. M. S. En- gel''. Fig. 47. Forewing of holotype female of Ctenoplectrella? sp. indet. Glaesosmia genalis, new species. Scale bar ϭ 1 Megachile sp. Gerlach, 1989: 255. [misidenti®- mm. cation] MATERIAL: One specimen. Non-type. Fe- male, Nr. G4669 (IMGP) labeled ``Reser- gent of compound eyes. Subantennal sutures vierte Registriernummer, Megachile: G4669 as long as antennal socket diameter. Com- [Gerlach handwriting]'' // ``Megachile sp. in- pound eyes bare; compound eye as broad as det., Gerlach, J., 1987'' // ``G4669, Cteno- gena in lateral view; inner margins straight plectrella sp. indet. (sensu Ckll.), det. M. S. and slightly converging below. F1 slightly Engel, 1999, Geologisch-PalaÈontologisches longer than F2; length of F2 approximately Institut und Museum, GoÈttingen''. equal to that of F3. Posterior margin of ver- COMMENTS: This specimen is poorly pre- tex gently concave. Preoccipital area round- served and is mostly covered by Schimmel ed. Mesoscutum and scutellum not coarsely except for portions of the compound eyes, an sculptured; mesoscutal anterior border broad- exposed wing, apices of the legs; other struc- ly rounded; median line moderately im- tures dimly visible through thinner regions of pressed; parapsidal lines moderately im- Schimmel. Those few visible features gen- pressed and linear; tegula oval; scutellum erally suggest a species of Ctenoplectrella low, weakly convex, not overhanging metan- (i.e., an osmiine without eye setae, relatively otum; propodeum not strongly sculptured. orthogonal second abscissa Rs to M, and Claws with inner tooth, inner tooth shorter with an apparently narrow gena). The strong- than outer; arolium present; outer apex of ly arcuate 2rs-m suggests C. cockerelli or C. mesotibia without spine; two metatibial grimaldii but further identi®cation as to spe- spurs, spurs serrate. Basal vein strongly ar- cies is impossible. The somewhat larger body cuate; second abscissa Rs forming an acute size (ca. 8 mm) suggests that the specimen angle with M (®g. 47). No apparent macu- may represent an otherwise unknown species lations on integument. (if indeed it is a true Ctenoplectrella at all!). ETYMOLOGY: The new genus-group name The body size is closer to that of Glaesosmia. is a combination of glaesum (Latin, meaning ``amber'') and the generic name Osmia. The Glaesosmia, new genus name is feminine. TYPE SPECIES: Glaesosmia genalis Engel, Glaesosmia genalis, new species new species. Figure 47 DIAGNOSIS: This genus is most similar to Ctenoplectrella but differs by the short su- DIAGNOSIS: As for the genus (see above). praclypeal area, broad gena, angulate second DESCRIPTION: Female. Total body length abscissa of Rs (®g. 47), and broad head (refer 7.15 mm; forewing length 5.05 mm. Head to key to genera, above). much wider than long (length 2.05 mm, DESCRIPTION: Mandible with three lower width 2.30 mm). Upper interorbital distance teeth along apical margin, upper tooth sepa- 1.50 mm; lower interorbital distance 1.45 rated from lower two teeth by a short, gently mm. Interocellar distance 0.40 mm; ocello- concave cutting-edge. Malar space short, cular distance 0.40 mm; median ocellus to much shorter than basal mandibular width. lateral ocellus 0.15 mm. Intertegular distance Clypeus ¯at; not extending below lower tan- 1.85 mm. Basal vein basad cu-a by vein 76 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 width; second abscissa Rs basad 1m-cu by legs generally simple and short; inner surface 10 times vein width; 2rs-m distad 2m-cu by of metafemur without pubescence, outer, an- vein width, 2rs-m doubly arcuate; second terior, and posterior surfaces with short, submarginal cell slightly longer than ®rst branched setae; metatibia with scattered, sim- submarginal cell, lower apical margin of sec- ple, moderate-length setae, a few with mi- ond submarginal cell extending apically; 10 nute branches. Central discs of metasomal distal hamuli, arranged in a single, evenly terga with sparse, minute, simple, appressed spaced series. setae, setae longer and erect to suberect on Clypeus with small punctures separated by lateral borders; sternal scopa composed of a puncture width or less, integument between dense, long, erect, simple setae. smooth. Supraclypeal area and face with MATERIAL: One specimen. Holotype. Fe- small punctures separated by a puncture male, B-JH 80 (AMNH) labeled: ``Baltic am- width or less, integument between smooth. ber: Eocene, Kaliningrad, Yantarny'' // ``Ho- Vertex and gena with sculpturing as on face, lotype, Glaesosmia genalis Engel''. although punctures slightly more widely ETYMOLOGY: The speci®c epithet is a ref- spaced, separated by about 0.5±1.5 times a erence to the enlarged gena (L. gena, mean- puncture width, integument between smooth. ing ``cheek''). Mesoscutum with small punctures separated by less than a puncture width, integument be- Family APIDAE Latreille tween smooth. Tegula with minute punctures DIAGNOSIS: Long-tongued bees lacking a separated by a puncture width or less, integ- strong metasomal scopa in nonparasitic ument between smooth. Scutellum sculptured forms and with the clypeus bent posteriorly as on mesoscutum. Metanotum rugulose. lateral to the narrowed labral articulation. PreeÈpisternal area (i.e., anterior-facing sur- DESCRIPTION: Single subantennal suture; face anterior to omaulus) essentially impunc- suture meeting lower margin of antennal tate and smooth except for a few, exceeding- socket. Facial foveae absent. Lower lateral ly faint, widely spaced, coarse punctures. margins of clypeus bent posteriorly on either Mesepisternum with small punctures sepa- side of labrum. Flabellum present; glossa rated a puncture width, integument between acute; labial palpus with ®rst two segments smooth, punctures becoming faint on poste- ¯attened, sheath-like, and elongate; submen- rior third. Metepisternum impunctate and tum strongly V-shaped and sclerotized, sub- smooth. Basal area and posterior surface of mental arms articulating with cardines propodeum ®nely imbricate and impunctate, slightly above cardo-stipital articulations. lateral surface ®nely imbricate with a few, Galeal comb absent; stipital comb and con- sparse, faint, small punctures. T1±T2 im- cavity present; basistiptial process elongate. punctate and smooth; remaining terga with PreeÈpisternal groove absent. Mesocoxa en- coarse, faint punctures separated by a punc- tirely exposed. Metabasitibial frequently pre- ture width, integument between smooth; ster- sent. Jugal lobe short. Strong metasomal sco- nal integument obscured. pa absent; scopa variously formed on meta- Coloration brown, without maculations. femur and metatibia, metatibia sometimes Wing membrane hyaline except between developed into a corbicula (in nonparasitic CϩSc and R slightly fuscous in some spec- females). Metapostnotum setose. Pygidial imens; veins dark brown. plate and ®mbria of female typically present. Clypeus with minute, appressed, simple setae not obscuring integument. Face, clyp- Key to Subfamilies of Apidae eus, supraclypeal area, gena, and postgena in Baltic Amber with scattered, short, erect or suberect, sim- 1. Metatibia modi®ed into corbicula; procoxa ple setae. Mesoscutum and scutellum with slightly wider than long or as long as wide; rastellum present (corbiculate Apinae) . . . scattered, short, simple setae. Pleural pubes- ...... Apinae Latreille cence as described for mesoscutum. Basal ± Metatibia not modi®ed into corbicula, typical area of propodeum without pubescence; lat- scopa present but reduced; procoxa much eral and posterior surfaces with pubescence wider than long; rastellum absent ..... as described for mesoscutum. Pubescence of ...... Xylocopinae Latreille 2001 ENGEL: BALTIC AMBER BEES 77

Subfamily XYLOCOPINAE Latreille the tribes Ceratinini and Allodapini; all three have the abruptly narrowed mandible (®g. Xylocopae Latreille 1802b: 379. Type genus: Xy- 54), have the anterior tentorial pit situation locopa Latreille, 1802b. near the middle of the clypeus (®g. 49), and DIAGNOSIS: Apid bees with distinctly have ¯attened labral surfaces (Xylocopini broadened procoxae and a reduced metatibial and Manueliini have tapering mandibles, the scopa. anterior tentorial pits situated well above the DESCRIPTION: Flabellum set at apex of bare middle of the clypeus, and basal labral ele- shank (Michener and Brooks, 1984). Procox- vations). From the Allodapini the new tribe ae wider than long; metatibial scopa reduced differs by having an elongate supraclypeal (in nonparasitic females), not developed into area (longer than the diameter of the antennal corbicula. sockets) (®g. 49), un¯attened distal metaso- COMMENTS: This morphologically diverse mal terga (®gs. 48, 53, 55), the lateral mar- subfamily of bees contains the familiar car- gins of the clypeus concave (not biconvex) penter bees of the genera Xylocopa and Cer- (®g. 49), and in the hind wing the ®rst ab- atina. The subfamily is partitioned into four scissa of M is more than three-quarters the tribes; the Allodapini of the Old World trop- length of the second abscissa of MϩCu (®g. ics and south temperate regions, the Man- 51). From the Ceratinini the boreallodapines ueliini of southern South America, and the can be distinguished by having only two sub- cosmopolitan tribes Ceratinini (small carpen- marginal cells (®g. 50) and lacking a meta- ter bees of the genera Ceratina and Mega- basitibial plate. ceratina; Pithitis is considered a subgenus of DESCRIPTION: Mandible abruptly narrowed Ceratina by Michener, 2000a) and Xyloco- near midpoint (®g. 54). Anterior tentorial pits pini (the large carpenter bees of the genus near (frequently slightly above) midpoint of Xylocopa; including Proxylocopa and Lestis clypeus; lateral margins of clypeus strongly according to Minckley, 1998). A key to these concave (®g. 49). Subantennal sutures longer four tribes was presented by Sakagami and than antennal socket diameter (i.e., supracly- Michener (1987) and Michener (2000a). In- peal area more elongate than that in Alloda- dividuals of Ceratinini and Xylocopini have pini in which the subantennal sutures are been discovered in various fossil deposits shorter than the diameter of the antennal sock- [Heer, 1849, 1865 (as Bombus); Cockerell, et) (®g. 49). Scape short, not reaching to me- 1906; Statz, 1936; Zeuner, 1938; Zhang, dian ocellus; F1 less than combined lengths 1990; Zhang et al., 1994; Engel, in press-a]; of F2ϩF3. Prosternum with short basisternum however, no Xylocopinae have previously and anterior process, lateral processes slightly been recorded as amber inclusions. These elongate, without constriction between basis- fossils are also the oldest record of the sub- ternum and furcasternum (®gs. 56±58); fur- family. A cladistic study of the subfamily is casternum elongate with strong medial groove presented below based on exemplar genera from apophyseal pit that extends slightly less (see Cladistic Analyses), while phylogenetic than three-quarters of total furcasternal length. studies on the relationships within Xyloco- Claw with strong inner tooth; arolium large pini have been undertaken by Minckley (®g. 52). Forewing membrane pubescent, not (1998) and for Allodapini by Reyes (1998). papillate; marginal cell apex rounded on wing Species of Manueliini were reviewed by margin (®gs. 50, 55); pterostigma of moderate Daly et al. (1987) but relationships were not size (not obsolete as in Xylocopini); prestig- explored cladistically. No cladogram has yet ma short; two submarginal cells (®gs. 50, 55); been produced for Ceratinini. hind wing with ®rst abscissa of M more than three-quarters length of second abscissa of BOREALLODAPINI, New Tribe MϩCu (®g. 51); jugal lobe one-half length of vannal lobe. Metabasitibial plate absent. Dis- TYPE GENUS: Boreallodape Engel, new ge- tal metasomal terga distinctly not ¯attened nus. dorsally (in Allodapini the distal three meta- DIAGNOSIS: Among xylocopine bees the somal terga are ¯attened dorsally) (®g. 55); boreallodapines are most closely related to pygidial ®mbria absent; pygidial plate absent. 78 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 48. Right lateral view of holotype female of Boreallodape baltica, new species.

Boreallodape, new genus behind ocelli strongly concave, vertex relatively short. Preoccipital area rounded. Gena TYPE SPECIES: Boreallodape baltica Engel, new species. narrower than compound eye in lateral view. Malar space short, much less than basal man- DIAGNOSIS: As for the tribe (see above). dibular width. Mandible bidentate (®g. 54). DESCRIPTION: As for the tribe with the following additions: Clypeus not protuberant in Mesoscutum broadly rounded anteriorly; me- lateral view, gently and slightly curved, dian and parapsidal lines moderately im- slightly extending below lower tangent of pressed. Tibial combs absent; coxae without compound eyes, with scattered, faint punc- spines or carinae. Wing membrane hyaline; tures; lateroclypeal carina absent; upper clyp- veins dark brown; basal vein strongly curved eal margin relatively straight. Antennal sock- (®gs. 50, 55); pterostigma well developed, ets slightly above level of middle of com- margin inside marginal cell slightly convex; pound eyes. Frons not protuberant. Vertex apex of marginal cell acutely rounded, set off from wing margin by width of vein at most; second submarginal cell shorter than ®rst; 1rs-m basad of 1m-cu; ®ve distal hamuli arranged in a single, evenly spaced series. ETYMOLOGY: The new genus-group name is derived from boreas (Greek, meaning ``north'') and Allodape, type genus of the xylocopine tribe Allodapini. The name is a combined reference to the resemblance of species of this tribe to those of their sister tribe Al- lodapini and to the fact that these fossils are Fig. 49. Frontal view of head of holotype fe- at the highest latitude recorded for any allo- male of Boreallodape baltica, new species. Scale dapine-like bee. The name is feminine. bar ϭ 0.5 mm. COMMENTS: Species of Boreallodape su- 2001 ENGEL: BALTIC AMBER BEES 79

Figs. 50±51. Wings of holotype female of Boreallodape baltica, new species. 50. Forewing. 51. Hind wing. Scale bar ϭ 0.5 mm. per®cially resemble the living allodapine ge- punctures of mesepisternum not nearly nus Braunsapis but can be immediately sep- contiguous, separated by 1±1.5 times a arated from the latter (as well as all other puncture width of smooth integument . . . Allodapini) by the tribal characteristics...... B. baltica, n. sp. ± Hypoepimeral area uniformly punctured; Key to Species of BOREALLODAPE punctures of mesepisternum nearly contig- 1. Pleura strongly punctate, punctures well-de- uous, when separated, then separated by ®ned, small and separated by a puncture less than a puncture width ...... width or less; tergal punctation closely ...... B. striebichi, n. sp. spaced, separated by a puncture width at most; basal area of propodeum variable; Boreallodape baltica, new species larger species (body length more than 4 Figures 48±52 mm) ...... 2 Plates 4a,b, 5b ± Pleura impunctate; tergal punctation minute and sparse, puncture separated by 1±3 DIAGNOSIS: This species is most similar to times a puncture width; basal area of propodeum glabrous; smaller species (body B. striebichi but can be distinguished by the length less than 4 mm) ...... glabrous basal area of the propodeum, the ...... B. mollyae, n. sp. more well-spaced pleural punctures (separat- 2. Lower half of hypoepimeral area impunctate; ed by smooth integument), and the presence 80 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

width. Tegula with small, faint punctures on inner two-thirds, punctures separated by 1±2 times a puncture width. Scutellum with small punctures separated by 2±3 times a puncture width, integument between smooth. Metano- tum with minute punctures separated by a puncture width or less, integument between smooth. Pleura strongly punctured, punctures approximately twice the diameter of those on mesoscutum, punctures separated by 1±1.5 times a puncture width except lower half of hypoepimeral area impunctate, integument between smooth. Metepisternum sculptured Fig. 52. Claw and arolium of holotype female like mesepisternum except punctures separat- of Boreallodape baltica, new species. Scale bar ed by a puncture width or less and slightly ϭ 0.25 mm. smaller. Basal area of propodeum, metapostnotum, and posterior surface of propodeum impunctate and smooth; lateral surface of pro- of a distinct impunctate region on the hypoe- podeum with small punctures separated by a pimeral area. puncture width, integument between smooth. DESCRIPTION: Female. Total body length First metasomal tergum impunctate; T2 with 4.47 mm; forewing length 2.56 mm. Head coarse, faint punctures separated by a punc- wider than long (length 1.03 mm, width 1.20 ture width or less except central disc impunc- mm). Upper interorbital distance 0.75 mm; tate and punctures bordering this area more lower interorbital distance 0.60 mm. Intero- widely separated and more faint; remaining cellar distance 0.22 mm; ocellocular distance terga with coarse, faint punctures separated by 0.17 mm; median ocellus to lateral ocellus a puncture width or less, without impunctate 0.08 mm. Intertegular distance 0.80 mm. zone on central discs. Basal vein distad cu-a by two times vein Integumental coloration not preserved. width; second abscissa Rs basad 1m-cu by Wing membrane hyaline; veins strong and four times vein width; 2rs-m relatively dark brown. straight, distad 2m-cu by two times vein Setae simple, minute or short, and sparse width; ®rst submarginal cell longer than sec- except those of sterna erect, short and more ond submarginal cell. dense. Labrum with small punctures separated by MATERIAL: Eight specimens. Holotype. Fe- 2±4 times a puncture width, integument be- male, B-JH 152 (AMNH) labeled ``Baltic am- tween smooth. Clypeus with exceedingly ber: Eocene, Kaliningrad, Yantarny'' // ``Ho- faint, small punctures sparsely scattered. Su- lotype, Boreallodape baltica Engel''. Para- praclypeal area sculptured as on clypeus. Re- type. Female, Nr. 1±5: 1967 (ZMUC) labeled: mainder of face with sparse, small punctures, ``Apidae, C. V. Henningsen, 1±5, 1967'' // integument between smooth, punctures be- ``Paratype, Boreallodape striebichi Engel''. come more closely packed (separated by two This specimen is missing the very apex of the times a puncture width) toward upper part of head (right mandible, lateral two-thirds of la- face and vertex, integument between smooth; brum, apex of right compound eye, and lateral small impunctate zone lateral to and bordering third of clypeus), which is right at the surface lateral ocellus, impunctate zone less than 1OD of the amber. There are also some thin layers in width and length. Gena with small punc- of Schimmel on the bee. tures separated by 1±2 times a puncture width, Paratype. Female, Nr. 810 (CDTG) la- integument between smooth; postgena sculp- beled: ``Nr. 810'' // ``Paratype, Boreallodape tured as on gena. Pronotum with small punc- baltica Engel''. tures separated by 1±2 times a puncture width, Paratype. Female, Nr. 873 (CHFG) la- integument between smooth. Mesoscutum beled: ``Nr. 873, Balt. Bernstein'' // ``Para- with small punctures separated by a puncture type, Boreallodape baltica Engel''. 2001 ENGEL: BALTIC AMBER BEES 81

Fig. 53. Dorsal view of holotype female of Boreallodape mollyae, new species.

Paratype. Female, Nr. 1253 (CHFG) la- mm). Upper interorbital distance 0.65 mm; beled: ``Nr. 1253, Balt. Bernstein'' // ``Para- lower interorbital distance 0.50 mm. Intero- type, Boreallodape baltica Engel''. cellar distance 0.18 mm; ocellocular distance Paratype. Female, Nr. 1256 (CHFG) la- 0.17 mm; median ocellus to lateral ocellus beled: ``Nr. 1256, Balt. Bernstein'' // ``Para- 0.08 mm. Intertegular distance 0.77 mm. type, Boreallodape baltica Engel''. Basal vein distad cu-a by two times vein Paratype. Female, Nr. 70 (CJDL) labeled: width; second abscissa Rs basad 1m-cu by ``Nr. 70'' // ``Paratype, Boreallodape baltica four times vein width; 2rs-m relatively Engel''. straight, distad 2m-cu by two times vein Non-type. Female, B-W 159 (AMNH) la- width; ®rst submarginal cell longer than sec- beled: ``Baltic amber: Eocene, Kaliningrad, ond submarginal cell. Yantarny'' // ``Boreallodape baltica? Engel, Labrum with small punctures separated by det. M. S. Engel''. 1±3 times a puncture width, integument be- ETYMOLOGY: The speci®c epithet is a ref- tween smooth. Clypeus with small punctures erence to the Baltic region where the amber separated by 2±3 times a puncture width. Su- originates. praclypeal area sculptured as on clypeus. Re- Boreallodape mollyae, new species mainder of face with sparse, small punctures, Figures 53, 54 integument between smooth, punctures be- Plates 4e, 5a coming gradually more closely spaced again DIAGNOSIS: This is the smallest species of (separated by 2±4 times a puncture width) on the genus. Boreallodape mollyae can be rec- upper part of face and vertex, integument be- ognized by the combination of impunctate tween smooth. Gena with minute punctures pleural integument (unique for the genus) separated by 3±4 times a puncture width, in- and minute and relatively sparse metasomal tegument between smooth; postgena with punctation. small punctures separated by 1±2 times a DESCRIPTION: Female. Total body length puncture width, integument between smooth. 3.68 mm; forewing length 2.34 mm. Head Pronotum impunctate, faintly imbricate. Me- wider than long (length 0.97 mm, width 1.13 soscutum with small punctures separated by 82 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

MATERIAL: Six specimens. Holotype. Fe- male, B-JH 81 (AMNH) labeled: ``Baltic amber: Eocene, Kaliningrad, Yantarny'' // ``Ho- lotype, Boreallodape mollyae Engel''. Paratypes. Five females, Nr. 19948 (ZMPA) labeled: ``Muzeum Ziemi w War- szawie, 19948, Baltic amber with bees, Ap- idae, from Baltic beach in Stupsk, 1983'' // ``Baltic Amber: Eocene, Nr. 19948, Muzeum Ziemi Pan, M. S. Engel study'' // ``Paratype, Boreallodape mollyae Engel''. ETYMOLOGY: The speci®c epithet is a pat- ronymic in loving honor of Ms. Molly G. Rightmyer, brilliant hymenopterist and gifted artist, who executed the numerous magni®- cent illustrations presented herein. Boreallodape striebichi, new species Figures 55±58 Plate 4c,d,f DIAGNOSIS: This species is most similar to the type species for the genus, B. baltica, but differs in the punctation of the pleura and sculpturing of the propodeum (refer to Di- agnosis for B. baltica). Fig. 54. Frontoventral oblique view of head DESCRIPTION: Female. Total body length of holotype female of Boreallodape mollyae, new 4.54 mm; forewing length 2.91 mm. Head species. Scale bar ϭ 0.5 mm. wider than long (length 1.13 mm, width 1.34 mm). Upper interorbital distance 0.84 mm; a puncture width, integument between lower interorbital distance 0.63 mm. Intero- smooth. Tegula with minute punctures, punc- cellar distance 0.28 mm; ocellocular distance tures separated by 1±2 times a puncture 0.22 mm; median ocellus to lateral ocellus width. Scutellum sculptured as on mesoscu- 0.13 mm. Intertegular distance 0.97 mm. tum. Metanotum with minute punctures sep- Basal vein distad cu-a by two times vein arated by 2±3 times a puncture width, integ- width; second abscissa Rs basad 1m-cu by ument between smooth. Mesepisternum im- four times vein width; 2rs-m relatively punctate and smooth except for a few ex- straight, distad 2m-cu by two times vein ceedingly faint punctures sparsely scattered, width; ®rst submarginal cell longer than sec- hypoepimeral area impunctate. Metepister- ond submarginal cell. num impunctate. Propodeum impunctate and Labrum with small punctures separated by smooth. T1±T2 impunctate; T3±T5 with mi- 2±4 times a puncture width, integument be- nute punctures separated by 2±3 times a tween smooth. Clypeus with faint, small puncture width, integument between smooth; punctures sparsely separated by 1±3 times a T6 with minute punctures separated by 1±2 puncture width. Supraclypeal area and face times a puncture width, integument between sculptured as on clypeus; punctures becoming smooth; sterna imbricate. more closely packed (separated by less than a Where preserved (mesoscutum, scutellum, puncture width) toward upper part of face and metasoma) integument dark brown and shin- vertex, integument between smooth; small im- ing with reddish-brown highlights. Wing punctate zone lateral to and bordering lateral membrane hyaline; veins dark brown. ocellus, impunctate zone less than 1OD in Setae simple, minute or short, and sparse width and length. Gena with small punctures except those of sterna erect, short and more separated by less than a puncture width, in- dense. tegument between ®nely imbricate; postgena 2001 ENGEL: BALTIC AMBER BEES 83

Fig. 55. Right dorsolateral habitus of holotype female of Boreallodape striebichi, new species. 84 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 56. Scanning electron micrograph of paratype female of Boreallodape striebichi, new species; partial specimen preserved at amber surface of B-BS 153 (AMNH). sculptured as on gena. Pronotum with small faintly imbricate. First metasomal tergum im- punctures separated by a puncture width or punctate; T2 with coarse, faint punctures sep- less, integument between ®nely imbricate. arated by a puncture width or less except Mesoscutum with small punctures separated punctures of central disc more widely sepa- by a puncture width, integument between rated and faint, without impunctate area; re- smooth. Tegula with minute, faint punctures maining terga with coarse, faint punctures on inner two-thirds, punctures separated by separated by a puncture width or less. two times a puncture width. Scutellum sculp- Integumental coloration dark brown where tured as on mesoscutum. Metanotum with mi- preserved. On some individuals yellow mark- nute punctures separated by a puncture width ings are easily apparent along the inner mar- or less, integument between smooth. Pleura gin of the compound eyes below the level of strongly punctured, punctures separated by the anterior tentorial pits as well as small ar- less than a puncture width or more often con- eas on the lateral apical borders of the clyp- tiguous, hypoepimeral area without impunc- eus. Wing membrane hyaline; veins dark tate zone, integument between (where evi- brown. dent) smooth. Metepisternum sculptured as on Setae simple, minute or short, and sparse mesepisternum. Basal area of propodeum, except those of sterna erect, short, and more metapostnotum, and posterior surface of pro- dense. podeum imbricate; lateral surface of propo- MATERIAL: Fourteen specimens. Holotype. deum with small punctures separated by less Female (pl. 4c, 4d), B-BS 153 (AMNH) la- than a puncture width, integument between beled: ``Baltic amber: Eocene, Kaliningrad, 2001 ENGEL: BALTIC AMBER BEES 85

Fig. 57. Scanning electron micrograph of paratype female of Boreallodape striebichi, new species. Magni®ed view of prosternum from ®gure 56.

Yantarny'' // ``Holotype, Boreallodape strie- the bend in the lateral margins and above the bichi Engel''. There are several specimens in anterior tentorial pits is shorter (thereby the this single piece (designated as paratypes be- supraclypeal area is correspondingly longer low). The holotype is the single individual than in the other species). Thus, the clypeus depicted in plate 4c, 4d. There is some pyr- is more plesiomorphic (more closely approx- rhite on the specimen (e.g., on supraclypeal imating that shape seen in Manueliini) than area) that makes the sculpturing dif®cult to other Boreallodape species. I presently inter- interpret in some areas. pret this species as the basalmost species of Paratypes. Eight whole females and ®ve Boreallodape. partial females, B-BS 153 (AMNH): in the same block of amber as the holotype. Boreallodape sp. indet. ETYMOLOGY: The speci®c epithet is a pat- ronymic honoring Herr Bernhard Striebich, MATERIAL: One specimen. Non-type. Fe- Buxtehude (Germany), who generously do- male, B-W 163 (AMNH) labeled: ``Baltic nated the holotype and its associated para- amber: Eocene, Kaliningrad, Yantarny'' // types to the AMNH. ``Boreallodape sp. indet., det. M. S. Engel.'' COMMENTS: The shape of the clypeus in COMMENTS: This specimen is mostly cov- this species appears to be slightly different ered by debris, and although the wing ve- from that of other Boreallodape. The lateral nation, metasoma, and legs can be examined margins of the clypeus are not as strongly easily, the remainder of the body cannot be concave and the portion of the clypeus above seen clearly. 86 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 58. Scanning electron micrograph of paratype female of Boreallodape striebichi, new species. Magni®ed and slightly oblique view of prosternum.

Subfamily APINAE Latreille tatibia with rastellum; auricle frequently pre- ``Corbiculate Apinae'' sent (except in parasitic forms and Melipon- ini). Wings uniformly setose. Prepygidial Apiariae Latreille, 1802a: 373. Type genus: Apis ®mbria and pygidial plate absent. Linnaeus, 1758. COMMENTS: The name ``corbiculate bees'', DIAGNOSIS: The corbiculate apines, as the or Corbiculata, was ®rst coined by Shuckard name implies, can be immediately recog- (1866: 165) for this specialized group of ap- nized by the modi®cation of the metatibia ine bees. This distinctive clade was once into a corbicula in nonparasitic females and considered as the family Apidae (e.g., Mich- workers. The presence of a rastellum, an ex- ener, 1965, 1990) with the other apids rele- panded mandibular pollex, as well as the ab- gated to the paraphyletic family Anthophor- sence of the metabasitibial plate and pygidial idae. The recent study of long-tongued bee plate also serve to distinguish this clade from phylogeny by Roig-Alsina and Michener other apines as well as the Xylocopinae (the (1993) resurrected the expanded concept of only other subfamily of Apidae presently Apidae as it was employed by Michener known in Baltic amber). At present, only the (1944) and the corbiculate bees were incor- corbiculate tribes of Apinae are known from porated into an expanded subfamily Apinae Baltic amber. without a separate, formal rank. Should a for- DESCRIPTION: Mandibular pollex expanded. mal rank be useful for recognizing the cor- Metatibia modi®ed into corbicula; metabasi- biculate apines, the supertribal name Apiti tibial plate absent; inner apical margin of me- could be applied. Presently, an apine clade 2001 ENGEL: BALTIC AMBER BEES 87 containing the non-corbiculate tribes Antho- bine (if a small jugal lobe is present in the phorini, Centridini, Melectini, and Ericroci- hind wing). Lastly, the stingless bees, tribe dini6 is believed to be the closest relative of Meliponini, are diverse pantropically. Spe- the corbiculate Apinae (refer to ®g. 123). cies are known in Late Cretaceous New Jer- This is the most common group of bees in sey amber (Michener and Grimaldi, 1988a, Baltic amber. Three of the living tribes are 1988b; Engel, 2000b), Miocene Dominican eusocial to varying degrees and the phylo- amber (Wille and Chandler, 1964; Michener, genetic position of the extinct corbiculate 1982; Camargo et al., 2000), Oligocene-Mio- groups suggests that they too were eusocial cene Mexican amber (Wille, 1959), Colom- (refer to sections on Cladistic Analyses, be- bian copal (Engel, personal obs.), Burmese low). This social lifestyle perhaps can ac- copal [Cockerell, 1921 (not Miocene am- count for their abundance in amber in com- ber!)], Sicilian amber [Tosi, 1896 (perhaps parison to other groups. Living corbiculate copal?)], and African copal [Engel, personal bees typically collect resins and it is possible obs.; Stuckenberg, 1975 (not Baltic amber!); that the fossil species described below did as Zeuner and Manning, 1976; Wille, 1977]. Of well, thus subjecting them more frequently all of these Recent tribes, only the melipon- to entrapment and fossilization. ines are presently known in Baltic amber. The corbiculate clade consists of four extant tribes, brie¯y summarized as follows: Key to Tribes of Corbiculate Apinae The Apini (honey bees) are originally an Old in Baltic Amber World group but have been spread throughout the world by humans for agricultural pur- 1. Distal wing venation complete (e.g., ®gs. 62, poses. Presently, fossils of Apini are only 68, 75, 77); marginal cell closed at apex; known from as far back as the early Oligo- metatibial spurs present (®g. 71); auricle cene (Engel, 1998c, 1999c). The Euglossini present (e.g., ®gs. 81, 90, 106); supra-alar (orchid bees) are strictly neotropical with carina present; claws with inner tooth (e.g., two species in Miocene amber from the Do- ®gs. 61, 108) ...... 2 minican Republic (Engel, 1999b) and one ± Distal wing venation incomplete (®gs. 111, extant species occurring in South American 113); marginal cell open at apex; metatibial copal (Engel, personal obs.; Ross, 1998). The spurs absent; auricle absent (®g. 114; su- bumble bees, tribe Bombini, are distributed pra-alar carina absent; claws simple (®g. 115) ...... throughout the western hemisphere, the Pa- . . Meliponini Lepeletier de Saint Fargeau learctic, and the Oriental regions. The report 2. Outer grooves of mandible present; hamuli of a bumble bee from tropical Africa (Tkal- not reduced, 10 or more (®g. 63); 1m-cu cuÊ, 1966) is actually based upon on an intro- not strongly angulate (e.g., ®gs. 62, 66); duced species from South America (Saka- one or two metatibial spurs present; robust, gami, 1976; Michener, 1979, 1990; Williams, Bombus-orApis-like bees ...... 3 1998). Numerous fossil bumble bees are ± Outer grooves of mandible absent; hamuli re- known [Heer, 1867; Unger, 1867; Novak, duced in number, less than 10 (®gs. 92, 1877; Cockerell, 1906 (as Calyptapis), 1931; 104, 110); 1m-cu short and strongly angu- Piton, 1940 (as Probombus); Zhang, 1990; late (®gs. 91, 103, 109); single metatibial Zhang et al., 1994; Rasnitsyn and Michener, spur present (®gs. 90, 102, 107); frequently 1991; Riou, 1999] but no true bombine has small, Trigona-like bees ...... yet been discovered in amber. The report of ...... Melikertini, n. tribe a bombine in Paleocene amber from France 3. Alar papillae absent (®gs. 66±68, 73±77, 85); outer mandibular grooves reduced but pre- (In Grimaldi, 1999) has yet to be con®rmed; sent; one metatibial spur present (®gs. 71, it is possible that this fossil is an electrobom- 83); marginal cell either weakly truncate or appendiculate ...... Electrapini Engel 6 Despite that shown in ®gure 123, relationships ± Alar papillae present (®gs. 62, 63); outer among these four non-corbiculate tribes are somewhat uncertain and nodes are not strongly supported. It is very mandibular grooves present and strong; likely that, once resolved, Anthophorini and Melectini two metatibial spurs present; marginal cell will be sister groups and together sister to a monophy- narrowly rounded at apex, not truncate or letic Centridini ϩ Ericrocidini clade. appendiculate . . . Electrobombini, n. tribe 88 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

ELECTROBOMBINI, New Tribe basal mandibular width. Epistomal sulcus forming obtuse angle (®g. 59). Inner margins TYPE GENUS: Electrobombus Engel, new of compound eyes slightly converging be- genus. low, not emarginate. F1 longer than F2±3 DIAGNOSIS: Robust Bombus-like bees that combined; F3 longer than F2. Preoccipital resemble in almost every respect the tribe ridge rounded. Mesoscutal anterior border Bombini; however, the presence of a distinct broadly rounded; scutellum projecting over jugal lobe at the base of the hind wing, a metanotum and basal area of propodeum. well-developed pterostigma that is much Basal area of propodeum apparently strongly larger than the prestigma, and a strongly de- declivitous. Keirotrichiate ®eld not elevated; veloped arolium serve to distinguish the metatibial spurs serrate; auricular basket electrobombines from bombines. Electro- sparse, setae short; rastellum strong and bombini can be separated from primitive formed of stiff setae; metabasitarsus twice as Electrapini by the presence of strongly de- long as wide. Margin of pterostigma within veloped outer mandibular grooves and two marginal cell straight; marginal cell apex off- elongate metatibial spurs. set from wing margin by slightly less than DESCRIPTION: Large (ca. 18 mm long), ro- pterostigma width, apex rounded, not appen- bust, densely pubescent bees. Mandible with diculate. strong outer mandibular grooves present. La- ETYMOLOGY: The new genus-group name bral width two times length (®g. 59). Clypeus is a combination of elektron (Greek, meaning slightly convex and weakly protuberant in ``amber'') and the generic name Bombus lateral view. Compound eyes bare. SupraaÈlar (originally taken from the Greek bombos, carina present; scutellum broadly rounded meaning ``buzzing'', which itself is related to posteriorly and projecting over metanotum bombylios, meaning ``bumble bee''). and (perhaps?) propodeum. Claws of female with inner tooth; arolium present and strong (®g. 61); two metatibial spurs present; malus Electrobombus samlandensis, new species of strigilis with short anterior velum in ad- Figures 59±63 dition to primary ventral velum; metabasitar- Plate 5c, e sus with distinct auricle at base (®g. 60); me- DIAGNOSIS: As for the genus. tatibia without penicillum (®g. 60). Distal ve- DESCRIPTION: Female. Total body length nation of forewing strong and present; mar- 18.78 mm; forewing length 10.50 mm. Head ginal cell large and narrowly rounded at longer than wide (length 3.40 mm, width apex, slightly offset from wing margin, not 3.24 mm). Upper interorbital distance 1.50 truncate or appendiculate, cell longer than mm; lower interorbital distance 1.45 mm. In- distance from its apex to wing apex (®g. 62); terocellar distance indeterminate (owing to pterostigma present and moderately sized, bubble that obscures the position of one lat- much longer than prestigma, r-rs arising eral ocellus); ocellocular distance 0.35 mm; slightly prior to its midpoint, margin within median to lateral ocellus 0.20 mm. Interte- marginal cell straight; 1m-cu relatively gular distance 3.75 mm. Basal vein basad cu- straight; hind wing with small but distinct ju- a by three times vein width; 1rs-m distad by gal lobe, lobe broadly incised (®g. 63); ham- 1m-cu by seven times vein width; 2rs-m dis- uli numerous (15 in a single series for Elec- tad 2m-cu by vein width; ®rst submarginal trobombus samlandensis); wing membrane cell shorter than second and third combined; papillate in outer margins (®gs. 62, 63). Sting length of anterior border of second submar- not reduced, not barbed. ginal cell one-half that of posterior border; length of anterior border of third submarginal Electrobombus, new genus cell one-half of that of posterior border, 1.5 TYPE SPECIES: Electrobombus samlanden- times length of anterior border of second sis Engel, new species. submarginal cell; 15 hamuli, arranged in a DIAGNOSIS: As for the tribe (see above). single, evenly spaced series. DESCRIPTION: Mandible with a few weak Integument, where visible between dense apical teeth. Malar space short, shorter than pubescence of head, mesosoma, and meta- 2001 ENGEL: BALTIC AMBER BEES 89

Figs. 59±61. Holotype female of Electrobombus samlandensis, new species. 59. Oblique frontal view of head. 60. Outer surface of metatibia and basal portion of metabasitarsus. 61. Claw and arolium. Scale bars ϭ 1mm(aϭ ®g. 60; b ϭ ®g. 59; c ϭ ®g. 61). soma, smooth and impunctate except face, Long corbicular setae with numerous, minute clypeus, and supraclypeal area with small, branches intermixed with long, simple setae. faint punctures separated by a puncture width Terga and sterna with minutely branched, or less, tegula with microscopic punctures dense, moderate-length, subappressed setae separated by 2±3 times a puncture width, and that partly obscure the integument. terga and sterna imbricate. MATERIAL: Two specimens. Holotype. Fe- Coloration of head and mesosoma black; male (caste indeterminate), B-JH 94 metasoma, antennae, and legs dark brown. (AMNH) labeled: ``Baltic amber: Eocene, Wing membrane hyaline; veins strong and Kaliningrad, Yantarny'' // ``Holotype, Elec- dark brown. trobombus samlandensis Engel''. Pubescence generally yellowish-white. Non-type. Female (caste indeterminate), Mandible with dense, minute setae in apical Nr. 500 (CJDL) labeled: ``Nr. 500'' // ''El- halves of outer grooves. Labrum with widely ectrobombus samlandensis?, det. M. S. En- scattered, short, simple, erect setae. Clypeus gel''. This individual is entirely covered in with scattered, erect setae, such setae slightly Schimmel. Those few characters that can be more numerous along lateral borders. Face determined suggest that the specimen is a with dense, short, appressed, plumose setae mostly obscuring integument intermixed second individual of E. samlandensis but this with longer, erect to suberect, plumose setae. will perhaps never be known with certainty. Vertex with long, plumose, erect setae. Gena The specimen is even larger than the holo- with pubescence as described for vertex ex- type and is the largest bee specimen known cept setae with only a few, minute branches. from Baltic amber (total body length 22 Mesosomal (dorsal, lateral, and ventral) pu- mm). bescence long, feathery plumose, and ex- ETYMOLOGY: The speci®c epithet is a ref- ceedingly dense, mostly obscuring integu- erence to the Samland Peninsula where most ment. Tegula with rather sparse, short, ap- Baltic amber has been uncovered. pressed setae not obscuring integument. COMMENTS: This is presently the largest 90 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 62±63. Wings of holotype female of Electrobombus samlandensis, new species. 62. Forewing. 63. Hind wing. Scale bar ϭ 1 mm. bee species preserved in amber (of any de- the jugal lobe, the presence of outer mandib- posit!). ular grooves, the single metatibial spur (entirely absent in Apini), the absence of long TRIBE ELECTRAPINI ENGEL, eye setae (some microscopic setae are pre- NOMEN TRANSLATUM sent in many specimens as is typical for many bees), and the shape of the marginal Electrapina Engel 1998a: 99. Type genus: Elec- and submarginal cells in the forewing, trapis Cockerell, 1908b. among other characters. DIAGNOSIS: The electrapine bees are a het- DESCRIPTION: Moderately sized (ca. 5.5±16 erogeneous group of three genera resembling mm long), robust, densely pubescent bees. either bumble bees (Bombini) or, to a much Mandible with weakened outer mandibular lesser degree, honey bees (Apini). From the grooves. Labral width 2±3 times length. former tribe electrapines differ by the pres- Clypeus slightly convex and weakly protu- ence of a jugal lobe, absence of alar papillae, berant in lateral view or ¯at (in Thaumasto- truncated or appendiculate marginal cell bombus). Compound eyes bare or with apex, reduction of the outer mandibular sparse, microscopic setae. SupraaÈlar carina grooves, and presence of only one, reduced present; scutellum broadly rounded posteri- metatibial spur. From the Apini, the electra- orly and variously produced (ranging from pines differ by the deep incision demarking projecting over metanotum and propodeum 2001 ENGEL: BALTIC AMBER BEES 91 to over metanotum only). Claws of female TABLE 8 with inner tooth (e.g., ®gs. 72, 83); arolium Hierarchical Classi®cation of Tribe strong and present; single, reduced metatibial ²Electrapini spur present; malus of strigilis with short, thickened anterior prong in addition to primary ventral velum (e.g., ®g. 82); metabasitarsus with distinct auricle at base; metatibia without penicillum. Distal venation of forewing strong and present; marginal cell large and narrowly rounded at apex, slightly offset from wing margin, truncate or feebly appendiculate, cell longer than distance from its apex to wing apex; pterostigma present and short to moderately sized, much longer than prestigma, r-rs arising near to just after midpoint, margin within marginal cell variously produced; 1m-cu relatively straight; hind wing with distinct jugal lobe, lobe broadly and deeply incised; hamuli numerous or reduced (numerous in Electrapis and Proto- bombus, reduced in Thaumastobombus); wing membrane without alar papillae. Sting not reduced; with or without microscopic barbs. one time placed in or near Electrapis by Kel- COMMENTS: There has been much confu- ner-Pillault (1970a), Manning (1960), Zeuner sion over the identity of Electrapis and its and Manning (1976), as well as myself (En- tribal position among the corbiculate bees. gel, 1998a), are reassigned to the Melikertini Recently I erected the Electrapina as a sub- or in a few instances to other electrapine gen- tribe of Apini to accommodate the nominate era following the results of the cladistic anal- genus as it had been conceived by more re- ysis presented below. cent authors (e.g., Zeuner and Manning, The tribe Electrapini, even after the re- 1976; Kelner-Pillault, 1970a; Engel, 1998a) moval of Melikertes and Roussyana, may but my recent revelations over the true iden- still be paraphyletic with respect to an Apini tity and nature of the type species (see below ϩ Meliponini ϩ Melikertini clade. Among in Comments under Electrapis and E. meli- the three genera of electrapines known, Elec- ponoides) have resulted in a radical reinter- trapis is the most plesiomorphic and resem- pretation of the group. Those bees believed bles not only Electrobombus (from which it to be Electrapis s.l. in recent decades, and differs most signi®cantly by the tribal char- thereby somewhat intermediate in character acters mentioned above) but living bombines between Apini and Meliponini are, in fact, as well. Protobombus appears somewhat in- members of the Melikertini (treated below). termediate between Electrapis and Thaumas- The electrapines are, in fact, intermediate in tobombus, the latter appearing most similar some respects between bombines and the to the higher corbiculates (i.e., Apini, Meli- Apini ϩ Meliponini clade (see Cladistic ponini, and Melikertini). However, there is Analyses, below). Cockerell's (1908b, presently not enough cladistic information to 1909b, 1909c) notes on the genus, as well as resolve the issue, and this scheme is pre- the genus Protobombus, clearly indicate sented only as a working hypothesis upon overall Bombus-like bees (although some which future studies can build. It is appro- have a de®nite Apis-like habitus) and provide priate to pose the possibility that electrapines the necessary characters to associate his spe- may represent a stem-group lineage from cies with the specimens described below as which the higher corbiculates originated. Ta- Electrapis and Protobombus. Other taxa (i.e., ble 8 summarizes the present classi®cation of those thought to resemble meliponines) at Electrapini. 92 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 64. Frontal view of head of female Electrapis martialis (Cockerell). Scale bar ϭ 1 mm.

Key to Genera of Electrapini sulcus forming orthogonal or obtuse angle (®g. 64). Inner margins of compound eyes 1. Metabasitarsus elongate, 1.5±2 times as long as maximum width (®g. 65) ...... slightly converging below, weakly emargin- ...... Electrapis Cockerell ate. F1 longer than F2, not longer than com- ± Metabasitarsus quadrangular, as long as max- bined lengths of F2 and F3; F3 longer than imal width (®gs. 70, 78, 81) ...... 2 F2. Preoccipital ridge rounded. Prosternum 2. Lateral margins of clypeus strongly concave, without constriction between basisternum epistomal sulcus forming an obtuse angle and furcasternum; similar in construction to opening toward compound eye (®g. 69) . . Bombus; apophyseal pit present. Mesoscutal ...... Protobombus Cockerell anterior border broadly rounded; scutellum ± Lateral margins of clypeus linear, epistomal sulcus straight (®gs. 79, 80) ...... projecting over metanotum and basal area of ...... Thaumastobombus, n. gen. propodeum. Basal area of propodeum strongly declivitous. Keirotrichiate ®eld not elevat- Genus Electrapis Cockerell, revised status ed; metatibial spur serrate; auricular basket sparse, setae short; rastellum strong and Electrapis Cockerell, 1908b: 326. Type species: formed of stiff setae; metabasitarsus 1.5±2 Apis meliponoides Buttel-Reepen, 1906, by designation of Cockerell, 1909b. Cockerell, 1909b: times as long as wide (®g. 65). Margin of 7. Zeuner and Manning, 1976: 227. pterostigma within marginal cell concave to Elektrapis Bischoff, 1927: 454. Lapsus calami. convex; marginal cell apex offset from wing Eckfeldapis Lutz, 1993: 180. Type species: Eck- margin by pterostigma width or more, apex feldapis electrapoides Lutz, 1993, monobasic either rounded and appendiculate or truncate. and original designation. Sting usually not barbed (except in some DIAGNOSIS: This genus can be separated specimens of Protobombus and one of Thau- from other genera in the tribe by the angled mastobombus microscopic barbs are appar- epistomal sulcus (®g. 64) and elongate me- ently present). tabasitarsus (®g. 65). COMMENTS: One species of Electrapis has DESCRIPTION: Mandible with a few, weak been discovered as a compression fossil in apical teeth. Malar space short, shorter than the middle Eocene oil-shale sediments of basal mandibular width (®g. 64). Epistomal Eckfelder Maar Formation [E. electrapoides 2001 ENGEL: BALTIC AMBER BEES 93

(Lutz) (Lutz, 1993; Engel, 1998a: 101)]. Upper interorbital distance 1.65 mm; lower With the splitting of Electrapis into multiple interorbital distance 1.30 mm. Interocellar genera, Eckfeldapis remains a junior syno- distance 0.50 mm; ocellocular distance 0.45 nym of Electrapis s.s. (e.g., elongate meta- mm; median to lateral ocellus 0.20 mm. In- basitarsus, identical wing venation). Elec- tertegular distance 2.55 mm. Basal vein ba- trapis electrapoides has not been included in sad cu-a by two times vein width, straight; the following key to species. second abscissa Rs relatively straight; 1rs-m An individual of a species of Electrapis distad 1m-cu by six times vein width; 2rs-m (GPUH Nr. 3001; see below) is preserved con¯uent with 2m-cu; ®rst submarginal cell with its dorsum open at the amber surface shorter than combined lengths of second and thereby allowing examination of the proster- third submarginal cells; posterior border of nal structure. It is from this individual that second submarginal cell 1.5 times length of the above de®nition of the Electrapis pro- anterior border; posterior border of third sub- sternal construction is based. marginal cell twice as long as anterior border, anterior border approximately equal to ante- Key to Species of ELECTRAPIS in rior border of second submarginal cell; pter- Baltic Amber ostigma longer than wide, margin inside mar- 1. Pterostigma size normal, longer than wide ginal cell straight; marginal cell bending (®g. 66) ...... 2 away from wing apex by pterostigmal width, ± Pterostigma exceptionally short, length equal feebly appendiculate; hind wing with 13 dis- to width (®g. 68) ...... tal hamuli arranged in a single, evenly ...... E. meliponoides (Buttel-Reepen) spaced series. 2. Labral apex without distinctive patches of Labrum smooth. Integument of face ob- elongate setae ...... 3 scured by ®ne layer of Schimmel (setae vis- ± Labral apex with patches of elongate setae ible extending out of this Schimmel and de- bordering midpoint ...... E. tornquisti Cockerell scribed below). Mesosoma ®nely imbricate 3. Apical margins of T2±5 with bands of dense, and impunctate except ventrally on mesepi- short, plumose setae; hind wing with ®rst ab- sternum with small punctures separated by a scissa M 3.5±4.5 times length of rs-m; fore- puncture width and mesoscutum and scutel- wing 2rs-m distad 2m-cu by at least twice lum with sparse, faint punctures separated by vein width ...... E. martialis (Cockerell) a puncture width or less. Metasomal terga ± Apical margins of T2±5 without bands of and sterna ®nely imbricate and impunctate. dense, short, plumose setae; hind wing with Color apparently dark brown without mac- ®rst abscissa M 1.5±2 times length of rs-m ulations. Wing membrane hyaline; veins (®g. 67); forewing 2rs-m con¯uent with brown. 2m-cu ...... E. krishnorum, n. sp. Pubescence white. Labrum with scattered, Electrapis martialis (Cockerell), erect, short, simple setae. Clypeus and supra- new combination clypeal area with scattered, moderate-length, Figure 64 simple setae, such setae more numerous on face and plumose, those setae of frons ap- Chalcobombus martialis Cockerell, 1908b: 326. pearing to be dense enough to have obscured Cockerell, 1909c: 22. Zeuner and Manning, integument if it were not already obscured 1976: 208. by ®ne layer of Schimmel. Setae on vertex DIAGNOSIS: Electrapis martialis is most quite long, fuscous, and with minute branch- similar to E. krishnorum but differs by the es by comparison to those setae of frons. Me- presence of dense, plumose bands on the api- soscutum with dense, long, erect, plumose cal margins of the metasomal terga, the more setae partially obscuring integument. Tegula distad position of 2rs-m in the forewing, and with short, appressed, simple setae, setae the more elongate ®rst abscissa of M in the with a few minute branches. Scutellar setae hind wing. very long (1.5±2 times length of those on DESCRIPTION: Female. Total body length mesoscutum, most setae as long as or longer 8.30 mm; forewing length 6.38 mm. Head than scutellum) and plumose; setae entirely wider than long (length 2.55, width 3.10). obscuring view of metanotum and propo- 94 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 65. Left lateral view of holotype female of Electrapis krishnorum, new species. Scale bar ϭ 1 mm. deum. Pleural pubescence long, dense, and JH 91 (AMNH) labeled ``Neotype, Chalco- plumose. Setae of legs long, numerous, and bombus martialis Cockerell, desig. M. S. En- stiff on tibiae and tarsi, and mostly plumose; gel'' // `Èlectrapis martialis (Cockerell), det. dense tuft of very long, sinuous, simple setae M. S. Engel''. on ventral surface of mesotrochanter, setae of Non-type. Female, worker caste, Nr. 502 tuft directed posteriorly; corbicula with long, (CJDL) labeled: ``Nr. 502'' // `Èlectrapis simple setae along lateral margins; sparse se- martialis (Cockerell), det. M. S. Engel''. tae on outer metabasitarsus. Metasomal terga with sparse, minute, appressed, simple setae Electrapis krishnorum, new species except on apical margins of T2±5 with bands Figures 65±67 of dense, short, plumose, suberect setae; ster- Apis sp. Gerlach, 1989: 257. [misidenti®cation] na with scattered, short, erect or suberect, simple setae. DIAGNOSIS: This species is most similar to MATERIAL: Two total specimens. Neotype E. martialis in that both are relatively small (here designated). Female, worker caste, B- by comparison to E. meliponoides and E. 2001 ENGEL: BALTIC AMBER BEES 95 tornquisti and both have pterostigmas that Pubescence silvery except those setae of are longer than wide while lacking distinc- vertex, tarsi, and apical terga slightly fus- tive setal patches on their labra. From E. cous. Mandible with a few, very short, wide- martialis, however, the new species differs ly scattered, simple setae except lower mar- by the absence of dense bands of plumose gin with long, simple, scattered setae. La- setae on the apical margins of T2±5, by the brum with scattered, erect, short, simple se- shortened ®rst abscissa of M in the hind tae. Clypeus and supraclypeal area with wing, and by the con¯uence of 2rs-m and scattered, moderate-length, simple setae, 2m-cu in the forewing. such setae more numerous on face and some DESCRIPTION: Female. Total body length with a few, minute branches, those setae of 9.30 mm; forewing length 6.40 mm. Head face partially obscuring integument. Setae on apparently wider than long (direct, frontal vertex quite long, slightly fuscous, and with view of head not possible). Mandibular more minute branches than those setae of grooves weakened, those present appear to face. Scape with minute, simple, scattered, be (from upper to lower margin) acetabular appressed setae. Postgena with scattered, groove, outer upper groove, and outer lower long, erect, simple setae. Mesoscutum with groove. Intertegular distance 2.15 mm. Basal dense, long, erect, plumose setae partially vein basad cu-a by vein width, straight; sec- obscuring integument. Tegula with short, ap- ond abscissa Rs relatively straight; 1rs-m dis- pressed, simple setae scattered on surface ex- tad 1m-cu by six times vein width; 2rs-m dis- cept anteriorly setae longer and with a few tad 2m-cu by vein width; ®rst submarginal minute branches. Scutellar setae very long cell shorter than combined lengths of second (at least 1.5 times length of those on mesos- and third submarginal cells; posterior border cutum, most setae as long as or longer than of second submarginal cell 1.25 times length scutellum itself) and plumose; setae entirely of anterior border; posterior border of third obscure view of metanotum and propodeum. submarginal cell nearly twice as long as an- Pleural pubescence long, dense, and either terior border, anterior border approximately simple or minutely plumose. Setae of legs equal to anterior border of second submar- long, numerous and stiff on tibiae and tarsi; ginal cell; pterostigma longer than wide, dense tuft of very long, sinuous, simple setae margin inside marginal cell slightly convex; on ventral surface of mesotrochanter, setae of marginal cell bending away from wing apex tuft directed posteriorly; corbicula with long by slightly less than pterostigma width, fee- setae along lateral margins; stiff scattered se- bly appendiculate; hind wing with 13 distal tae on outer metabasitarsus and stiff comb hamuli arranged in a single, evenly spaced rows on inner surface. Metasomal terga with series; ®rst abscissa M slightly less than sparse, minute, simple, appressed setae, terga twice as long as rs-m. without apical setal bands; sterna with scat- Mandibular integument smooth except ap- tered, short, erect, simple setae. pearing minutely granular within weakened MATERIAL: Four specimens. Holotype. Fe- mandibular grooves. Labrum minutely gran- male, worker caste, II1926 (BMNH) labeled: ular. Clypeus and supraclypeal area with `ÌI1926(1)'' // ``Bombus?, Baltic amber''// coarse, faint punctures separated by two `Èlectrapis'' // ``Holotype, Electrapis krish- times a puncture width or more, integument norum Engel''. between smooth. Face, vertex, gena, and Paratype. Female, worker caste, 5589 postgena smooth and impunctate. Mesosoma (ZMPA) labeled: ``Muzeum Ziemi w War- smooth and impunctate except ventrally on szawie, 5589 (in two pieces), Apidae in Bal- mesepisternum; posteriorly and laterally on tic Amber, Gerlach 1989: Apis L., Electrapis: mesoscutum and scutellum faint punctures det. Engel, Golarisk-Stogi, coll. T. Gierew- separated by a puncture width or less. Me- icz, 1972'' // ``Baltic Amber, Eocene, 5589, tasomal terga and sterna ®nely imbricate and Muzeum Ziemi Pan, M. S. Engel study'' // impunctate. ``Paratype, Electrapis krishnorum Engel''. Color apparently dark brown, without Paratype. Female, worker caste, Nr. 25 maculations. Wing membrane hyaline; veins (CSUL) labeled: ``Paratype, Electrapis krish- dark brown. norum Engel''. 96 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 66±67. Wings of holotype female of Electrapis krishnorum, new species. 66. Forewing. 67. Hind wing. Scale bar ϭ 1 mm.

Paratype. Female, worker caste, Nr. 71 Electrapis cockerelli Bischoff In Kelner-Pillault, (CJDL) labeled: ``Nr. 71'' // ``Paratype, Elec- 1974: 624. Nomen nudum [ϭ Electrapis bom- trapis krishnorum Engel''. busoides Kelner-Pillault, 1974]. Electrapis cokerelli Kelner-Pillault, 1974: 624. ETYMOLOGY: The speci®c epithet is a pat- ronymic honoring my dear friends and col- Lapsus calami. Electrapis bombusoides Kelner-Pillault, 1974: leagues Drs. Kumar and Valerie Krishna, 625. NEW SYNONYMY. world's authorities on termites and medieval literature, respectively. DIAGNOSIS: Electrapis tornquisti, like E. meliponoides, is a larger species than E. mar- Electrapis tornquisti Cockerell tialis and E. krishnorum. The species can be distinguished from E. meliponoides by the Electrapis tornquisti Cockerell, 1908b: 326. Cockerell, 1909c: 23. Zeuner and Manning, longer pterostigma and the presence of me- 1976: 231. dioapical patches of elongate setae on the la- Electrapis hermenaui Bischoff In Kelner-Pillault, brum. 1974: 624. Nomen nudum [ϭ Electrapis bom- DESCRIPTION: Female. Total body length busoides Kelner-Pillault, 1974]. 15.16 mm; forewing length 9.17 mm. Head 2001 ENGEL: BALTIC AMBER BEES 97 longer than wide (length 4.41 mm, width fuscous as in E. krishnorum), and minutely 3.91 mm). Upper interorbital distance 2.72 plumose. Mesoscutum with dense, long, mm; lower interorbital distance 2.09 mm. erect, plumose setae partially obscuring in- Basal vein basad cu-a by three times vein tegument. Scutellar setae very long, dense, width, straight; second abscissa Rs relatively and plumose. Pleural pubescence long, straight; 1rs-m distad 1m-cu by seven times dense, and minutely plumose. Setae of legs vein width; 2rs-m distad 2m-cu by two times long, numerous, and stiff on tibiae and tarsi; vein width; ®rst submarginal cell shorter than inner surface of metafemur covered by kei- combined lengths of second and third sub- rotrichiae except medially this ®eld narrows marginal cells; posterior border of second slightly; corbicula with long setae along lat- submarginal cell 1.5 times length of anterior eral margins, inner surface of metatibia en- border; posterior border of third submarginal tirely covered by keirotrichiae; stiff scattered cell twice as long as anterior border, anterior setae laterally on metabasitarsus, outer sur- border slightly less than length of anterior face with sparse, simple setae, inner surface border of second submarginal cell; pterostig- with comb rows. Metasomal terga with scat- ma longer than wide, margin inside marginal tered, simple or minutely plumose setae, api- cell slightly concave; marginal cell bending cal margins of terga with dense bands of away from wing apex by pterostigmal width, short, plumose setae; sterna with scattered, feebly appendiculate; hind wing with 17 dis- erect, simple setae. tal hamuli arranged in a single, evenly MATERIAL: Three specimens. Neotype spaced series; ®rst abscissa M four times lon- (tornquisti; here designated). Female, ger than rs-m. worker caste, MB.I.1947 (ZMHB) labeled: Mandibular integument smooth except ap- ``Neotype, Electrapis tornquisti Cockerell, pearing minutely granular within weakened desig. M. S. Engel [red label]''. This is also mandibular grooves. Labrum minutely gran- the holotype specimen of E. bombusoides ular. Clypeus and supraclypeal area with and bears additional labels reading: `Èlec- coarse, faint punctures separated by two trapis bombusoides n. sp., Holotype, S. Kel- times a puncture width or more, integument ner-Pillault'' // ``PalaÈont. Mus. Berlin, coll. between smooth. Face, vertex, gena, and KuÈhl [actually from the Berendt collection]'' postgena ®nely imbricate and impunctate. // ''Electrapis hermanaui, Bisch., Paratypus, Mesosoma ®nely imbricate and impunctate 1930'' // `Èlektrapis [sic] hermanaui, 20'' / except some sparse, faint punctures on me- / ``Holotyp [sic], PalaÈontologisches Museum soscutum and scutellum. Metasomal terga Berlin, Electrapis bombusoides Kelner-Pil- and sterna ®nely imbricate; terga impunctate; lault, 1974, slg. Berendt''. S1±2 apparently impunctate, S3±5 minutely Holotype (bombusoides). Same specimen punctured on apical thirds, S6 minutely as neotype of E. tornquisti (above). punctured on apical half, punctures on all Paratype (bombusoides). Female, worker sterna separated by 1±3 times a puncture caste, MB.I.1948 (ZMHB) labeled: ``27'' // width. ``Paratype, Electrapis bombusoides'' // Color, where evident, dark brown without ``MB.I.1948'' // ``Paratyp [sic], PalaÈontolo- maculations. Wing membrane hyaline; veins gisches Museum Berlin, Electrapis bombu- black. soides Kelner-Pillault, 1974''. Pubescence white except those setae of Non-type. Female, worker caste (IMGP) protibia and tarsi black. Mandible with a few, labeled: `Èlectrapis bombusoides n. sp., det. very short, widely scattered, simple setae ex- S. Kelner-Pillault [in Kelner-Pillault's hand- cept lower margin with long, simple, scat- writing]'' // `Èlectrapis cockerelli Bisch., tered setae. Labrum with scattered, erect, Paratype, 1930'' // `Èlectrapis cockerelli short, simple setae and apical margin with Bisch., Paratypus, 1930'' // ``27 Electrapis mediolateral patches of elongate, simple se- Cockerelli [sic] Bisch., Chalcobombus? hu- tae. Clypeus and supraclypeal area with scat- milis Cockerell, Electrapis bombusoides S. tered, moderate-length, simple setae, setae Kelner P.'' // ``60±21, Electrapis bombuscoi- more numerous on face and minutely plu- des [sic] n. sp., Kelner-Pillault, Geologisch- mose. Setae on vertex quite long, white (not PalaÈontologisches Institut GoÈttingen'' // 98 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

``Chalcobombus humilis Cock. [stricken through], Electrapis Cockerelli [sic] Bisch.''. This specimen is very poorly preserved and is only tentatively placed in E. tornquisti. COMMENTS: At ®rst notice the specimen from GoÈttingen labeled as C. humilis and then as E. cockerelli might be considered as the missing type of C. humilis and simply misinterpreted by Bischoff and Kelner-Pil- Fig. 68. Forewing of neotype female of Elec- lault as Electrapis. However, Chalcobombus trapis meliponoides (Buttel-Reepen). Scale bar ϭ was de®ned as having a quadrangular meta- 1 mm. basitarsus (among other features) and this is not the case with the fossil (the metabasitarsus being twice as long as broad; typical of erell, 1908b: 326. Cockerell, 1909b: 9. Zeuner Electrapis). I therefore concur with Bischoff and Manning, 1976: 229. and Kelner-Pillault that this cannot be Cock- DIAGNOSIS: Electrapis meliponoides is dis- erell's missing type (a neotype for C. humilis tinctive among all known Electrapis species is designated below). Moreover, the labels for the shortened pterostigma. The species is reading Chalcobombus are all in Bischoff's large like E. tornquisti but lacks the me- handwriting; none are in Cockerell's distinc- dioapical patches of setae on the labrum. tive script. DESCRIPTION: Female. Total body length Bischoff had originally intended to pro- 12.60 mm; forewing length 8.88 mm. Head duce a paper on this material and to sum- longer than wide (length 2.85 mm, upper marize the then known bees in Baltic amber width 2.40 mm: lower width not preserved under the title `Àpiden des Bernsteins'' (to owing to damage to lower right of head). In- have appeared in the 1939 volume of Bern- tertegular distance 3.40 mm. Basal vein ba- stein Forschungen); however, this paper was sad cu-a by vein width, straight; second ab- never published. Kelner-Pillault subsequently scissa Rs arched; 1rs-m distad 1m-cu by ®ve borrowed this material from Berlin and pre- times vein width; 2rs-m distad 2m-cu by four pared a description of Bischoff's specimens. times vein width; ®rst submarginal cell short- At that time she mentioned the unpublished er than combined lengths of second and third species names with which Bischoff had la- submarginal cells; posterior border of second beled the specimens (i.e., E. hermenaui, E. submarginal cell 1.25 times length of anterior cockerelli). Under Recommendation 50C border; posterior border of third submarginal (ICZN, 1999b) authorship of these unavail- cell twice as long as anterior border, length able names should be attributed to Bischoff of anterior border slightly less than anterior in Kelner-Pillault. border of second submarginal cell; pterostig- In Kelner-Pillault's (1974) illustration of ma short, as long as wide, margin inside mar- the hind wing of the holotype female of E. ginal cell slightly concave; marginal cell bombusoides she omitted the jugal lobe and bending away from wing apex by nearly the wing drawing therefore strongly resem- twice pterostigma width, feebly appendicu- bles that of a true bombine. The holotype late; hind wing with 13 distal hamuli ar- specimen clearly has a jugal lobe present at ranged in a single, evenly spaced series; ®rst the base of the hind wing; this structure is abscissa M 4.5 times as long as rs-m. even more apparent in the specimen she Preserved portion of facial integument ob- chose as a paratype. scured by ®ne layer of Schimmel; where evident, appearing imbricate. Mesosoma and metasoma, where evident, ®nely imbricate. Electrapis meliponoides (Buttel-Reepen) Color dark brown without maculations. Figure 68 Wing membrane hyaline; veins dark brown. Plate 6c Pubescence white. Mandible with a few, Apis meliponoides Buttel-Reepen, 1906: 158. very short, widely scattered, simple setae ex- Electrapis meliponoides (Buttel-Reepen); Cock- cept lower margin with long, simple, scat- 2001 ENGEL: BALTIC AMBER BEES 99 tered setae. Labrum with scattered, erect, stein'' // `Èlectrapis sp. indet., det. M. S. long, simple setae. Clypeus and supraclypeal Engel''. area with scattered, moderate-length, simple setae, such setae more numerous on face and Electrapis sp. indet. some with a few minute branches; those setae of face fairly dense and plumose. Setae MATERIAL: One specimen. Non-type. Fe- on vertex quite long and simple. Genal setae male?, Nr. 461 (GPUH) labeled: ``Nr. 461 as described for vertex except much shorter. (Scheele), Apis meliponoides Buttel-Reepen Mesoscutum with dense, long, erect, plu- ϭ Electrapis meliponoides (Buttel-Reepen)'' mose setae partially obscuring integument. // `Èlectrapis sp. indet., det. M. S. Engel''. Tegula with dense, long, appressed, plumose COMMENTS: This specimen was identi®ed setae directed laterally. Scutellar setae as de- by Zeuner and Manning (1976) as belonging scribed for mesoscutum except along poste- to E. meliponoides but the individual is en- rior third exceedingly long (longer than scu- tirely covered by fractures, Schimmel, and tellum) and plumose. Pleural pubescence pyrite and such an indenti®cation cannot ac- long, dense, and plumose. Setae of legs long, tually be made. The size of the specimen is numerous and stiff on tibiae and tarsi; cor- about that of E. meliponoides. bicula with long setae along lateral margins, setae of anterior margin simple, posterior Electrapis sp. indet. margin minutely plumose; inner surface of MATERIAL: One specimen. Non-type. Fe- metatibia entirely covered by keirotrichiae; male, worker caste, Nr. 19±00937 (CGHG) stiff, elongate, scattered setae on lateral mar- labeled: ``Nr. 19±00937'' // `Èlectrapis sp. gins of metabasitarsus, outer surface with indet., det. M. S. Engel''. sparse, shorter, simple setae, inner surface with dense ®eld of setae not arranged into Electrapis sp. indet. rows. Metasomal terga with scattered, short, plumose setae, apparently with dense, apical MATERIAL: Three specimens. Non-type. bands on T2±5; sterna with scattered, long, Females worker caste? (CMGG) labeled: erect or suberect, minutely plumose setae. `Èlectrapis sp. indet., det. M. S. Engel''. MATERIAL: One specimen. Neotype (here designated). Female, worker caste, B-JH 97 Electrapis sp. indet. (AMNH) labeled: ``Baltic amber: Eocene, Kaliningrad, Yantarny'' // ``Neotype, Apis MATERIAL: One specimen. Non-type. Fe- meliponoides Buttel-Reepen, desig. M. S. male, worker caste, 3001 (GPUH) labeled: Engel'' // `Èlectrapis meliponoides (Buttel- `Èlectrapis sp. indet., det. M. S. Engel, Reepen), det. M. S. Engel''. 1999''. COMMENTS: This individual is preserved with its dorsum at the amber surface and its Electrapis cf. krishnorum mesosoma and metasoma opened. The inter- MATERIAL: One specimen. Non-type. Fe- nal sclerites are preserved and can be ex- male, worker caste, Nr. 501 (CJDL) labeled: amined with some ease. The generic identi- ``Nr. 501'' // `Èlectrapis sp., det. M. S. En- ®cation of the specimen is still possible ow- gel''. ing to the relatively good preservation of the ventral half of the bee and it can be assigned COMMENTS: This specimen represents a species near to E. krishnorum but has dis- to Electrapis with con®dence. Speci®c iden- tinctive differences in both the wing venation ti®cation, however, is not possible. It is from as well as the mouthparts. this individual that the above de®nition of the prosternal shape in Electrapis was made.

Electrapis sp. indet. Genus Protobombus Cockerell MATERIAL: One specimen. Non-type. Fe- Protobombus Cockerell, 1908b: 326. Type spe- male, worker caste, Nr. 577/2 (CHFG) la- cies: Protobombus indecisus Cockerell, 1908b, beled: ``Nr. 577/2, Bittf. [Bitterfeld] Bern- monobasic [also designated by Cockerell, 100 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

1909b]. Cockerell, 1909b: 9. Manning, 1960: 306. Zeuner and Manning, 1976: 231. Chalcobombus Cockerell, 1908b: 326. Type species: Chalcobombus humilis Cockerell, 1908b [ϭ Protobombus indecisus Cockerell, 1908b], by designation of Cockerell, 1909b; isotypic with Protobombus Cockerell, 1908b by synonymy. Cockerell, 1909b: 11. Zeuner and Man- ning, 1976: 206. NEW SYNONYMY. Sophrobombus Cockerell, 1908b: 326. Type species: Sophrobombus fatalis Cockerell, 1908b, monobasic [also designated by Cockerell, 1909c]. Cockerell, 1909c: 21. Zeuner and Man- ning, 1976: 213. NEW SYNONYMY.

DIAGNOSIS: Electrapine bees with a short, quadrangular metabasitarsus; similar in this respect to Thaumastobombus (described below). Protobombus differs from Thaumasto- bombus most notably, however, in the obtuse angle formed by the epistomal sulcus. Some Protobombus, like Thaumastobombus, have a super®cial Apis-like habitus. DESCRIPTION: Mandible with a few, weak apical teeth. Malar space shorter than basal mandibular width. Epistomal sulcus forming obtuse angle (®g. 69). Inner margins of com- Fig. 69. Frontal view of head of neotype fe- pound eyes parallel, not emarginate (®g. 69). male of Protobombus indecisus Cockerell. Scale F1 longer than F2, not longer than combined bar ϭ 1 mm. lengths of F2 and F3; F3 longer than F2. Pre- occipital ridge rounded. Mesoscutal anterior border broadly rounded; scutellum projecting ell, 1908b, 1909c). The type specimen of S. over metanotum and basal area of propo- fatalis has been lost but Zeuner and Manning deum. Basal area of propodeum strongly de- (op. cit.) located a specimen in the Scheele clivitous. Keirotrichiate ®eld not elevated; Collection (presently in the Geologisch-Pa- metatibial spur serrate or minutely ciliate; au- laÈontologisches Institut und Museum, Univ- ricular basket sparse, setae short; rastellum ersitaÈt Hamburg) that matches Cockerell's strong and formed of stiff setae; metabasi- description in all respects. This specimen is tarsus as long as wide. Margin of pterostigma here designated as the neotype for S. fatalis. within marginal cell convex; marginal cell The presence of only two submarginal cells apex offset from wing margin by pterostigma is not the same ``forewing venation reduc- width or slightly less, apex rounded and fee- tion'' as is diagnostic for Meliponini. In me- bly appendiculate. Sting variable, usually not liponines the distal wing veins (i.e., 2rs-m barbed (some specimens appear to have mi- and 2m-cu) are lost, the marginal cell is typ- croscopic barbs). ically open, and frequently other veins are COMMENTS: The genus Sophrobombus was also missing or greatly reduced. None of regarded as a genus of Meliponini by Zeuner these are true for S. fatalis. The presence of and Manning (1976) because the forewing a single inner metatibial spur, of an auricle, venation was apparently ``reduced''. The a supra-alar carina, an inner tooth on the type species, Sophrobombus fatalis Cocker- claw, as well as numerous other characters ell, is notable for the presence of only two separate this species from the Meliponini. submarginal cells owing to the apparent ab- Sophrobombus is actually an electrapine bee sence of 1m-cu (i.e., the second transverso- and similar in all respects to species of Pro- cubital vein in Cockerell's system) (Cocker- tobombus, differing only in the number of 2001 ENGEL: BALTIC AMBER BEES 101 submarginal cells. Cockerell (1908b), who maringal cell twice length of anterior bor- did not ally this species with the stingless der (®g. 77) .....P. hirsutus (Cockerell) bees (see ®g. 120), separated Sophrobombus ± Keirotrichiate ®eld of metatibial inner surface from Protobombus by the number of sub- separated from metatibial apex by glabrous zone that is equal to width of keirotrichiate marginal cells and by the basal vein being ®eld in length (®g. 71); posterior margin of basad cu-a in the former. Below I describe a third submarginal cell thrice length of an- new species (P. basilaris) that blends the de- terior border ..... P. indecisus Cockerell ®ning characters of the ``genera'' (i.e., basal vein basad cu-a but with three submarginal Protobombus indecisus Cockerell cells). I have therefore placed Sophrobombus Figures 69±73 as a junior synonym of Protobombus. Plate 6a,b Chalcobombus was differentiated from Protobombus by the shape the pterostigma as Protobombus indecisus Cockerell, 1908b: 326. well as the third submarginal cell. The shape Cockerell, 1909b: 10. of the third submarginal cell varies among Chalcobombus humilis Cockerell, 1908b: 326. the species of Electrapini and, although spe- NEW SYNONYMY. cies-speci®c characters can be identi®ed, Electrapis (Electrapis) apoides Manning, 1960: 307. Zeuner and Manning, 1976: 227. NEW SYN- these differences in shape are not correlated ONYMY. with other structural characters. Similarly, Electrapis (Protobombus) indecisus (Cockerell); the shape of the pterostigma is quite variable Zeuner and Manning, 1976: 232. and was incongruent with all other characters (including the shape of the third submarginal DIAGNOSIS: This species can be recognized cell!). Chalcobombus appears to be synony- by the combination of three submarginal mous with Protobombus. cells, apical third of clypeus below lower tangent of compund eyes, and the keirotri- Key to Species of PROTOBOMBUS chiate ®eld on the inner surface of the metatibia separated from metatibial apex by dis- 1. Forewing with three submarginal cells (i.e., tance equal to its own apical width. 1rs-m present) (®gs. 75, 77) ...... 2 DESCRIPTION: Female. Total body length ± Forewing with two submarginal cells (i.e., 8.31 mm; forewing length 7.38 mm. Head 1rs-m absent) (®g. 74) ...... wider than long (length 2.34 mm, width 2.63 ...... P. fatalis (Cockerell) mm). Upper interorbital distance 1.56 mm; 2. Basal vein con¯uent with cu-a (®g. 77); hind lower interorbital distance 1.50 mm. Intero- wing with ®rst abcissa of M approximately equal in length to second abcissa of MϩCu cellar distance 0.38 mm; ocellocular distance (®g. 73) ...... 3 0.38 mm; median to lateral ocellus 0.09 mm. ± Basal vein basad cu-a by twice vein width Lower half of clypeus below lower tangent (®g. 75); hind wing with ®rst abcissa of M of compound eyes. Intertegular distance 2.15 distinctly shorter than second abcissa of mm (measured from second specimen in am- MϩCu (®g. 76) ..... P. basilaris, n. sp. ber piece). Basal vein con¯uent with cu-a, 3. Apical third of clypeus extending below low- straight; second abscissa Rs relatively er tangent of compound eyes; keirotrichiate straight; 1m-cu basad 1rs-m by seven times ®eld of metatibial inner surface separated vein width; 2rs-m distad 2m-cu by three from metatibial apex by glabrous zone of times vein width, strongly arched; anterior variable length ...... 4 border of second submarginal cell approxi- ± Clypeus not extending below lower tangent mately one-third length of posterior border; of compound eyes; keirotrichiate ®eld of posterior border of third submarginal cell metatibial inner surface separated from metatibial apex by glabrous zone that is half slightly more than twice length of anterior width of keirotrichiate ®eld in length .... border, anterior border twice as long as an- ...... P. tristellus Cockerell terior border of second submarginal cell; 4. Keirotrichiate ®eld of metatibial inner surface hind wing with 10 distal hamuli arranged in separated from metatibial apex by glabrous a single, evenly spaced series; hind wing zone that is half width of keirotrichiate ®eld with ®rst abscissa M approximately equal in in length; posterior margin of third sub- length to second abscissa MϩCu. 102 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 70±72. Leg structures of neotype female of Protobombus indecisus Cockerell. 70. Outer surface of metatibia and metabasitarsus. 71. Inner surface of metatibia. 72. Claw and arolium. Scale bars ϭ 0.25 mm (a), 1 mm (b); (a ϭ ®g. 72; b ϭ ®gs. 70, 71).

Labrum imbricate and impunctate. Clype- tures, integument between ®nely imbricate. us with sparse, small, faint punctures, integ- Propodeum faintly imbricate and impunctate. ument between faintly imbricate. Supracly- Corbicula smooth and impunctate. Metaso- peal area, face, vertex, gena, and postgena mal terga and sterna ®nely imbricate. with sparse, small, faint punctures, integu- Where evident integument dark brown and ment between smooth. Pronotum ®nely im- shining. Wing membrane very lightly fus- bricate. Mesoscutum and scutellum with cous; veins dark brown. sparse, faint punctures, integument between Pubescence golden. Labrum with short, faintly imbricate. Metanotum imbricate and scattered, erect, simple setae. Clypeus with impunctate. Pleura with sparse, small punc- scattered, short, simple, suberect setae inter-

Fig. 73. Hind wing of neotype female of Protobombus indecisus Cockerell. Scale bar ϭ 1 mm. 2001 ENGEL: BALTIC AMBER BEES 103 mixed with scattered, minute, appressed, Holotype (apoides). Female, worker caste simple setae. Face below level of antennal (MNHN). Not seen. I have based my iden- sockets with appressed, short, minutely plu- ti®cation on photographs of the holotype mose setae, setae numerous but not obscur- specimen as well as illustrations of the wing ing integument; supraclypeal area, vertex, venation and descriptive notes given by both gena, and remainder of face with scattered, Manning (1960) and Kelner-Pillault (1970a). simple, suberect or erect setae a few on ver- From this information it is quite clear that E. tex and gena with minute branches. Postgena apoides does not belong in Electrapis (see with scattered, short, erect, simple setae. comments below) and is, in fact, conspeci®c Pronotum with sparse, short, suberect simple with the specimen designated above as the setae except along posterior border and cov- neotype for P. indecisus. ering pronotal lobe with moderately long, Non-type. Female, worker caste, B-JH 98 erect, dense, plumose setae. Mesoscutum (AMNH) preserved in same piece with neo- with scattered, short to moderate length, type (see above). erect, minutely plumose setae. Tegula with Non-type. Female, worker caste, Nr. 1521 short, scattered, minutely plumose setae an- (CCGG) labeled: ``Nr. 1521'' // ''Protob- teriorly, posteriorly with minute, simple se- ombus indecisus Cockerell, det. M. S. En- tae. Scutellar setae as described for mesos- gel''. cutum except setae dense on posterior border COMMENTS: Although I was not able to ex- and on axilla. Metanotum with sparse, mi- amine the holotype of E. apoides, the place- nute, appressed, simple setae. Pleura with ment of this species in Protobombus is sim- short, scattered, erect, simple setae except a ple owing to the quadrate metabasitarsus not few with minute branches. Lateral and pos- only described in the original paper by Man- terior surfaces of propodeum as described for ning (1960) and by Zeuner and Manning pleura except setae minute; basal area of pro- (1976), but also nicely depicted in the pub- podeum without pubescence. Corbicular se- lished photograph of the holotype by Kelner- tae mostly simple but a few minutely plu- Pillault (1970a). Additionally, the con¯uence mose also with a few minute setae on cor- of the basal vein among other characters bicular surface itself (®g. 70), inner surface clearly shown in the photograph all suggest of metatibia mostly covered by keirotrichiate that this species is conspeci®c with Cocker- ®eld, ®eld separated from metatibial apex by ell's P. indecisus. The line illustrations of the length approximately equal to its width; me- wing venation presented by Kelner-Pillault tabasitarsus with scattered, short, simple se- (1970b) are quite poor and I have not trusted tae, posterior edge with longer setae, inner them, instead referring to the descriptions surface with 5±6 comb rows. Metasomal ter- and other illustrations. In fact, the holotype ga with sparse, minute, appressed, simple se- of E. apoides agrees quite well with not only tae; sterna with suberect to erect, moderately Cockerell's descriptive notes about P. inde- long, scattered setae, each with a few minute cisus but also with the specimens designated branches, setae entirely postgradular. here as neotypes. I therefore feel con®dent in MATERIAL: Four specimens. Neotype (in- the above synonymy. decisus; here designated). Female, worker caste, B-JH 98 (AMNH) labeled: ``Baltic Protobombus fatalis (Cockerell), amber: Eocene, Kaliningrad, Yantarny'' // new combination ``Neotype, Protobombus indecisus Cockerell, Figure 74 desig. M. S. Engel''. There are two individuals in the same block of amber; the neotype Sophrobombus fatalis Cockerell, 1908b: 326. Cockerell, 1909c: 21. Zeuner and Manning, is the one ®gured in plate 6b and the right- 1976: 214. hand bee in plate 6a. Neotype (humilis; here designated). DIAGNOSIS: This species is immediately Same specimen as the neotype of P. indeci- recognizable for the complete absence of 1rs- sus (above); bears one additional label read- m in the forewing thus forming only two ing: ``Neotype, Chalcobombus humilis Cock- submarginal cells (®g. 74). The basal vein is erell, desig. M. S. Engel''. basad cu-a and therefore resembles to some 104 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

tae. Scutellar setae as described for mesoscutum. Mesepisternum with short, scattered, erect, simple setae except a few with minute branches. Corbicular setae mostly simple and sinuous, also with three elongate, simple, sinuous setae on corbicular surface, corbicula occupying glabrous region on lower four- ®fths of metatibia, inner surface of metatibia covered by keirotrichiate ®eld, ®eld separat- Fig. 74. Forewing of neotype female of Pro- ed from metatibial apex by length approxi- tobombus fatalis (Cockerell). Scale bar ϭ 1 mm. mately equal to its width; metabasitarsus with scattered, short, simple setae, posterior degree P. basilaris. The mandible of P. fa- edge with longer setae, inner surface with talis bears a strong, broad subapical tooth seven comb rows. Metasomal terga with (see Material and Comments, below). sparse, minute, appressed, simple setae; ster- DESCRIPTION: Female. Total body length na with suberect, moderately long, scattered, 5.82 mm; forewing length 3.91 mm. Head simple setae, setae entirely postgradular. slightly wider than long (length 1.91 mm, MATERIAL: Two specimens. Neotype (here width 1.94 mm). Mandible with strong, designated). Female, Nr. 1225 (GPUH) la- broad subapical tooth; tooth separated from beled: ``Neotype, Sophrobombus fatalis remainder of the apical mandibular margin Cockerell, desig. M. S. Engel'' // ``Geol.-Pa- by deep incision. Interocellar distance 0.38 laÈont. Inst. Univ. Hamburg, Nr. 1225 (Schee- mm; ocellocular distance 0.34 mm; median le) Sophrobombus fatalis Cockerell'' // to lateral ocellus 0.16 mm. Intertegular dis- ``Protobombus fatalis (Cockerell), det. M. S. tance 1.59 mm. Basal vein basad cu-a by Engel, 1999''. This specimen is poorly pre- three times vein width, straight; second ab- served with the ventral portion of the head scissa Rs arched; 1m-cu distad second ab- lost into a series of fractures that eventually scissa Rs by seven times vein width; 2rs-m lead into a cavity on the lower surface of the distad 2m-cu by three times vein width, amber piece. This cavity appears to open into strongly arched; second submarginal cell ex- what would have been the lowermost portion tremely elongate owing to absence of 1rs-m. of the head and the anteroventral area of the Face above antennal sockets, vertex and mesosoma. In addition, numerous small frac- gena ®nely imbricate and impunctate. Pron- ture planes and ®ne layers of Schimmel ob- otum ®nely imbricate and impunctate. Me- scure various structures of the bee. It can soscutum and scutellum faintly imbricate and still, however, be placed con®dently into the impunctate. Mesepisternum sculptured as on species as de®ned by Cockerell owing to the mesoscutum. Corbicula smooth and impunc- preservation of the metatibia, metabasitarsus, tate. Metasomal terga and sterna ®nely im- and forewing venation, all of which indicate bricate. this specimen to be conspeci®c with Cock- Coloration not preserved. Wing membrane erell's original material. hyaline; veins brown. Non-type. Female, collection of Michael Pubescence whitish. Face above level of BaÈaÈtjer (Hamburg, Germany) labeled: ``Pro- antennal sockets and vertex with scattered, tobombus fatalis (Cockerell), det. M. S. En- simple or minutely branched, erect setae. gel, 2000''. Although this specimen is in bet- Gena with sparse, minute, appressed, simple ter condition than the neotype, it is part of a setae. Pronotum with sparse, short, suberect, private collection and is presently available simple setae except along posterior border for purchase; thus, the ®nal depository of this and covering pronotal lobe with moderately specimen remains unknown. In the interest long, erect, dense, plumose setae. Mesoscu- of stability I have therefore chosen the less tum with scattered, short to moderate length, perfect individual to serve as the neotype erect, minutely plumose setae. Tegula with since the whereabouts of this specimen will short, scattered, minutely plumose setae an- certainly change in the coming months and teriorly, posteriorly with minute, simple se- years rendering it dif®cult, if not impossible, 2001 ENGEL: BALTIC AMBER BEES 105

to locate again. This specimen was received DESCRIPTION: Female. Total body length at the time when the remainder of the man- 6.63 mm; forewing length 5.50 mm. Head uscript was going to press. It was therefore wider than long (length 2.06 mm, width 2.38 not possible to prepare illustrations. In all mm). Interocellar distance 0.34 mm; ocello- comparable features this specimen is conspe- cular distance 0.34 mm; median to lateral ci®c with the neotype designated above. The ocellus 0.13 mm. Lower half of clypeus be- abdomen is unfortunately distended and por- low lower tangent of compound eyes. Inter- tions of the legs and mesosoma cleared in tergular distance 1.72 mm. Basal vein basad preservation but is otherwise a nice speci- cu-a by twice vein width, straight; second ab- men. It is from this specimen that informa- scissa Rs arched; 1m-cu basad 1rs-m by sev- tion on the mandibular structure of P. fatalis en times vein width; 2rs-m distad 2m-cu by was extracted. Similarly, information on the vein width, strongly arched; posterior border structure of other characters (e.g., the epis- of second submarginal cell approximately tomal sulcus) can all be seen in this individ- three times length of anterior border; poste- ual and con®rms the placement of P. fatalis rior border of third submarginal cell 1.75 in the Electrapini and Protobombus. Further- times length of anterior border, anterior bor- more, the information provided by this new der twice as long as anterior border of second material helps to reinforce the identity of the submarginal cell; hind wing with 10 distal neotype as well as this specimen for being hamuli arranged in a single, evenly spaced conspeci®c with Cockerell's (1908b, 1909c) series. missing original material. Labrum ®nely imbricate and impunctate; COMMENTS: The specimen I studied was remainder of head and entirety of mesosoma the same one examined by Zeuner and Man- and metasoma smooth and impunctate. ning (1976); see comments above for syn- Integument dark brown and shining. Wing onymy of the genus Sophrobombus with membrane hyaline; veins black. Protobombus. Cockerell (1909c) noted that Pubescence whitish. Labrum with short, his monotypic Sophrobombus was very scattered, erect, simple setae. Clypeus with much like Protobombus and Chalcobombus scattered, short, simple, suberect setae. Face, (above considered as synonyms) but differed supraclypeal area, vertex, and gena with scat- most notably by the presence of only two tered, simple, suberect or erect setae, those submarginal cells. The specimen described on vertex and gena with minute branches. by Cockerell (1908b, 1909c) agrees in every Pronotum with sparse, minute, suberect, sim- respect with the one selected here as the neo- ple setae except along posterior border and type, particularly in the unique trait of having covering pronotal lobe with short, erect, plu- only two submarginal cells. Cockerell's orig- mose setae and a few elongate, plumose setae inal specimen lacked mandibular dentition on dorsolateral angle that are slightly fus- (differing in this respect from the non-type cous. Mesoscutum with scattered, short to specimen examined here); it is possible that moderate length, erect, minutely plumose se- the mandibles were simply worn or set close tae. Tegula with sparse, appressed, minute the the face where the large subapical tooth setae. Scutellar setae as described for mesos- would be completely obscured (for instance, cutum except setae dense and elongate on in the available specimen the labrum and posterior border. Pleura with short, scattered, clypeus totally cover the subapical tooth of erect, simple setae. Lateral and posterior sur- one mandible while the other, more fully faces of propodeum as described for pleura opened, displays this character nicely). except setae minute; basal area of propodeum without pubescence. Corbicular setae Protobombus basilaris, new species mostly simple but a few minutely plumose Figures 75, 76 also with a few minute setae on corbicular surface itself, inner surface of metatibia DIAGNOSIS: This species is notable for the mostly covered by keirotrichiate ®eld, ®eld position of the basal vein that is basad cu-a. separated from metatibial apex by length ap- Protobombus fatalis is similar in this respect proximately equal to its width; metabasitar- but has only two submarginal cells. sus with scattered, short, simple setae, pos- 106 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 75±77. Wings of Protobombus species. 75. Forewing of Protobombus basilaris, new species. 76. Hind wing of P. basilaris, new species. 77. Forewing of P. hirsutus (Cockerell). Scale bars ϭ 1 mm (a ϭ ®g. 76; b ϭ ®gs. 75, 77). 2001 ENGEL: BALTIC AMBER BEES 107 terior edge with longer setae. Metasomal ter- with sparse, small punctures, integument be- ga with sparse, minute, appressed, simple se- tween smooth. Propodeum smooth and im- tae; sterna with suberect to erect, short, punctate. Corbicula smooth and impunctate. scattered setae, each with a few minute Metasomal terga smooth and impunctate; branches, setae entirely postgradular. sterna ®nely imbricate and impunctate except MATERIAL: One specimen. Holotype. Fe- apical margins more strongly imbricate. male, worker caste, MB.I.1939 (ZMHB) la- Where evident, integument dark brown beled: ``Museum fuÈr Naturkunde Berlin, Pa- and shining. Wing membrane hyaline; veins laÈontologisches Museum, Inv. Nr. MB.I.1939 dark brown. (No. 36)'' // ``36 [handwritten label]'' // Pubescence whitish. Labrum with short, ``Holotype, Protobombus basilaris Engel''. scattered, erect setae. Clypeus with scattered, ETYMOLOGY: The speci®c epithet is the short, simple, suberect setae intermixed with Greek word basilaris, meaning ``at the scattered, minute, appressed, simple setae. base'', and is a reference to the basal position Face below level of antennal sockets with ap- of the basal vein relative to cu-a. pressed, short, minutely plumose setae, setae numerous but not obscuring integument; su- Protobombus tristellus Cockerell praclypeal area, vertex, gena, and remainder of face with scattered, suberect or erect, sim- Protobombus tristellus Cockerell, 1909c: 24. ple setae, setae of vertex and gena with mi- Electrapis (Protobombus) tristellus (Cockerell); Zeuner and Manning, 1976: 233. nute branches. Postgena with scattered, short, erect, simple setae. Pronotum with sparse, DIAGNOSIS: This species is similar to P. in- short, suberect, simple setae except those of decisus and P. hirsutus but can be distin- dorsolateral angle and pronotal lobe dense, guished from both by the apical margin of moderately long, erect, and plumose setae. the clypeus not extending below the lower Mesoscutum with scattered, short, erect, mi- tangent of compound eyes. nutely plumose setae. Tegula with sparse, ap- DESCRIPTION: Female. Total body length pressed, scattered, minutely plumose setae. 6.13 mm; forewing length 5.13 mm. Head Scutellar setae as described for mesoscutum wider than long (length 1.78 mm, width 2.31 except setae dense and elongate on posterior mm). Upper interorbital distance 1.47 mm; border. Mesepisternum with moderately long, lower interorbital distance 1.25 mm. Intero- scattered, erect, simple setae and intermixed cellar distance 0.44 mm; ocellocular distance with scattered, minute, appressed, simple se- 0.39 mm; median to lateral ocellus 0.09 mm. tae; hypoepimeral area without longer setae, Lower third of clypeus below lower tangent only with minute, appressed setae; metepis- of compound eyes. Intertegular distance 1.72 ternum with setae as on mesepisternum ex- mm. Basal vein con¯uent with cu-a, straight; cept simple and distinctly more dense on dor- second abscissa Rs arched; 1m-cu basad 1rs- sal half than on ventral half. Setae of lateral m by six times vein width; 2rs-m con¯uent and posterior surfaces of propodeum as de- 2m-cu, strongly arched; posterior border of scribed for ventral half of metepisternum ex- second submarginal cell 2.5 times length of cept setae minute; basal area of propodeum anterior border; posterior border of third sub- without pubescence. Corbicular setae mi- marginal cell twice length of anterior border, nutely plumose, inner surface of metatibia anterior border 1.5 times as long as anterior mostly covered by keirotrichiate ®eld, ®eld border of second submarginal cell. separated from metatibial apex by length ap- Labrum imbricate and impunctate. Clype- proximately equal to one-half its width; meus with small, faint punctures separated by tabasitarsus with scattered, short, simple se- 1±2 times a puncture width, integument be- tae, posterior edge with longer setae, inner tween smooth. Supraclypeal area, face, ver- surface with seven comb rows. Metasomal tex, gena, and postgena with sparse, small, terga with sparse, minute, appressed, simple faint punctures, integument between smooth. setae, slightly longer on more apical terga; Pronotum smooth and impunctate. Mesos- sterna with suberect to erect, short to mod- cutum and scutellum with sparse, faint punc- erately long, scattered setae, each with a few tures, integument between smooth. Pleura minute branches, setae entirely postgradular. 108 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

MATERIAL: One specimen. Neotype (here Schimmel and sundry small items of debris. designated). Female, worker caste, MB.I.1943 Pleura impunctate ®nely imbricate. Corbicula (ZMHB) labeled: ``Museum fuÈr Naturkunde with remains presumably of pollen covering Berlin, PalaÈontologisches Museum, Inv. Nr. surface. Metasomal terga and sterna ®nely MB.I.1943'' // ``50b [handwritten label]'' // imbricate. ``Neotype, Protobombus tristellus Cockerell, Where evident, integument dark brown desig. M. S. Engel''. and shining. Wing membrane very lightly fuscous; veins dark brown. Protobombus hirsutus (Cockerell), Pubescence whitish or slightly fuscous. new combination Labrum with short, scattered, erect, simple Figure 77 setae. Clypeus with scattered, short, simple, Plate 5d suberect setae intermixed with scattered, minute, appressed, simple setae. Face below Chalcobombus hirsutus Cockerell, 1908b: 326. level of antennal sockets with appressed, Cockerell, 1909b: 12. Zeuner and Manning, 1976: 207. short, minutely plumose setae, setae numerous but not obscuring integument; supracly- DIAGNOSIS: This species is most similar to peal area, vertex, gena, and remainder of face P. indecisus but differs by the separation of with scattered, simple, suberect or erect se- the keirotrichiate ®eld from the metatibial tae, a few on vertex and gena with minute apex being equal to one-half of its apical branches. Postgena with scattered, short, width and the posterior border of the third erect, simple setae. Pronotum with sparse, submarginal cell only twice as long as the short, suberect, simple setae except along anterior border. posterior border and covering pronotal lobe DESCRIPTION: Female. Total body length with moderately long, erect, dense, plumose 8.01 mm; forewing length 6.38 mm. Head setae. Pubescence of mesosomal dorsal sur- wider than length (length 2.19 mm, width face dif®cult to interpret, those mesoscutal 2.25 mm). Upper interorbital distance 1.41 setae appearing through layer of Schimmel mm; lower interorbital distance 1.19 mm. In- and debris appearing to be scattered, mod- terocellar distance 0.44 mm; ocellocular dis- erate-length, erect, and minutely plumose; tance 0.34 mm; median to lateral ocellus 0.13 scutellar setae as described for mesoscutum mm. Lower half of clypeus below lower tan- except setae dense on posterior border and gent of compound eyes. Intertegular distance more elongate. Pleura with scattered, long, 1.88 mm. Basal vein con¯uent with cu-a, erect, simple setae. Lateral and posterior sur- straight; second abscissa Rs arched; 1m-cu faces of propodeum as described for pleura basad 1rs-m by six times vein width; 2rs-m except setae minute; basal area of propo- distad 2m-cu by vein width, strongly arched; deum without pubescence. Corbicular setae posterior border of second submarginal cell simple, inner surface of metatibia covered by approximately ®ve times length of anterior keirotrichiate ®eld, ®eld separated from me- border; posterior border of third submarginal tatibial apex by length approximately equal cell 1.75 times length of anterior border, an- to one-half its width; metabasitarsus with terior border slightly more than twice as long scattered, short, simple setae, posterior edge as anterior border of second submarginal with longer setae. Metasomal terga with cell; hind wing with eight distal hamuli ar- sparse, minute, appressed, simple setae; ster- ranged in a single, evenly spaced series; hind na with scattered, long, erect, fuscous, simple wing with ®rst abscissa M approximately setae along apical margins. equal in length to second abscissa MϩCu. MATERIAL: Four specimens. Neotype Labrum imbricate and impunctate. Clype- (here designated). Female, worker caste, B- us with sparse, small, faint punctures, integ- JH 92 (AMNH) labeled: ``Baltic amber: Eo- ument between faintly imbricate. Supracly- cene, Kaliningrad, Yantarny'' // ``Neotype, peal area, face, vertex, gena, and postgena Chalcobombus hirsutus Cockerell, desig. M. with sparse, small, faint punctures, integu- S. Engel'' // ``Protobombus hirsutus (Cock- ment between smooth. Pronotum ®nely im- erell), det. M. S. Engel''. bricate. Dorsum of mesosoma obscured by Non-type. Female, worker caste (CJVG) 2001 ENGEL: BALTIC AMBER BEES 109 labeled: ''Protobombus hirsutus (Cockerell), gel (1999c), references to the shape of the det. M. S. Engel''. ®rst submarginal cell should refer to the third Non-type. Female, worker caste, Nr. 1254 submarginal cell]. Among electrapines, (CHFG) labeled: ``Nr. 1254, Balt. Bernstein'' Thaumastobombus is most similar to Proto- // ``Protobombus hirsutus (Cockerell), det. bombus, both sharing the quadrangular me- M. S. Engel''. tabasitarsus. The former differs, however, by Non-type. Female, worker caste, Nr. 1255 the linear epistomal sulcus and weakly emar- (CHFG) labeled: ``Nr. 1255, Balt. Bernstein'' ginate compound eyes that converge below. // ``Protobombus hirsutus (Cockerell), det. DESCRIPTION: Mandible with a few, weak M. S. Engel''. apical teeth along upper half. Malar space short, shorter than basal mandibular width. Protobombus sp. indet. Clypeus ¯at, not protuberant in lateral view. Epistomal sulcus linear (®g. 80). Inner mar- MATERIAL: One specimen. Non-type. Fe- gins of compound eyes slightly converging male, Nr. 2608 (CCGG) labeled: ``Nr. 2608'' below, weakly emarginate (®gs. 79, 80). F1 // ''Protobombus sp. indet., det. M. S. En- longer than F2, not longer than F2±3 com- gel''. bined; F3 longer than F2. Mesoscutal anterior border broadly rounded; median and par- Protobombus sp. indet. apsidal lines moderately impressed; scutel- MATERIAL: One specimen. Non-type. Fe- lum projecting over metanotum and basal male, Nr. 1962.I.262 (BSPG): labeled ``Bay- area of propodeum. Basal area of propodeum er. St. Slg. PalaÈont. Hist. Geol. (BSP), Nr. strongly declivitous (®g. 78). Keirotrichiate 1962.I.262, Apidae, Honigbiene, Unteroli- ®eld not elevated; metatibial spur pectinate gozaÈn, Ostpreussen'' // ``Protobombus sp. in- (®gs. 83, 84); auricular basket dense, setae det., det. M. S. Engel, 1999''. long (®g. 81); rastellum strong and formed COMMENTS: This specimen is in exceed- of stiff setae (®g. 83); metabasitarsus about ingly poor shape. The bee is almost com- as long as wide (®g. 81). Margin of pteros- pletely pyritized. The general habitus, prestigma within marginal cell convex; marginal ence of a corbicula, and quadrangular meta- cell apex offset from wing margin by slightly basitarsus suggests a species of Protobom- less than pterostigma width, apex appendi- bus. The identity of this specimen will culate (®g 85). Worker gonostyli minutely probably never be known with any reason- setose at apices (®g. 78); sting not barbed able degree of certainty. (except see Thaumastobombus cf. andreniformis). Thaumastobombus, new genus ETYMOLOGY: The new genus-group name is a combination of the Greek words thau- TYPE SPECIES: Thaumastobombus andren- mastos (meaning ``wonderful'') and bombos iformis Engel, new species. (meaning ``buzzing''; a derivative of bom- DIAGNOSIS: This group super®cially resem- bylios meaning ``bumble bee''). The name is bles in its general habitus a short-tongued masculine. bee (either an andrenine, rophitine, or mel- ittine) as well as the dwarf honey bees [Ap- Thaumastobombus andreniformis, ini, Apis (Micrapis)] (®g. 78; pl. 5f). It, how- new species ever, readily falls away from the former by Figures 78±85 being a long-tongued bee and a corbiculate Plate 5f apine at that. From the latter it differs in the tribal characters [Apini lacks metatibial spurs DIAGNOSIS: As for the genus (see above). and outer mandibular grooves, has elongate DESCRIPTION: Female. Total body length eye hairs, an elongate malar space, among 6.92 mm; forewing length 4.45 mm. Head other features: refer to Engel (1999c) for a slightly wider than long (length 1.62 mm, diagnosis of the honey bees and their con- width 1.70 mm). Upper interorbital distance stituent groups; however, note that in the sub- 1.10 mm; lower interorbital distance 0.80 generic diagnoses for Apis presented in En- mm. Interocellar distance 0.45 mm; ocello- 110 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 78. Left dorsolateral habitus of holotype female of Thaumastobombus andreniformis, new species. Scale bar ϭ 1 mm.

cular distance 0.25 mm; median to lateral Integument of head and mesosoma smooth ocellus 0.14 mm. Distal third of clypeus set and impunctate. Terga and sterna imbricate. below lower tangent of compound eyes. In- Coloration not well preserved, apparently tertegular distance 1.20 mm. Basal vein ba- black and shining except antennae, metaso- sad cu-a by vein width; 1rs-m distad 1m-cu ma, and legs dark brown; without macula- by seven times vein width; 2rs-m distad 2m- tions. Wing membrane hyaline; veins strong cu by 2.5 times vein width; marginal cell and dark brown. apex separated from wing margin by one- Pubescence generally pale. Labrum with half pterostigma width, feebly appendiculate; sparse, simple, erect setae. Setae of face nu- ®rst submarginal cell shorter than second and merous, simple, appressed, and short, each third combined; second submarginal cell nar- with a few, minute branches, setae partially rowed, anterior border just less than one- obscuring integument, such setae intermixed third length of posterior border, anterior bor- with sparse, erect, minutely branched setae; der just less than one-half length of anterior setae most dense on face below level of an- border of third submarginal cell; anterior tennal sockets and lateral to clypeus; ap- border of third submarginal cell just less than pressed setae disappearing by vertex and one-third length of posterior border; seven erect setae becoming gradually more numer- distal hamuli, arranged in a single, evenly ous. Gena with appressed setae like those of spaced series. face; postgena with sparse, erect, moderate- 2001 ENGEL: BALTIC AMBER BEES 111

Fig. 79. Frontal view of head of holotype female of Thaumastobombus andreniformis, new species. 112 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Sterna with dense, apical bands of moderate to long, simple setae. MATERIAL: One specimen. Holotype. Fe- male, worker caste, B-JH 164 (AMNH) labeled: ``Baltic amber: Eocene, Kaliningrad, Yantarny'' // ``Holotype, Thaumastobombus andreniformis Engel''. ETYMOLOGY: The speci®c epithet is a reference to the super®cial habitus of the species that resembles a short-tongued bee. The species also resembles to some degree the dwarf honey bees (A. ¯orea and A. andreniformis), which also resemble short-tongued bees.

Thaumastobombus cf. andreniformis

MATERIAL: Two specimens. Non-type. Two females, worker caste, Nr. 9 (CSUL) labeled: ``Thaumastobombus cf. andreniformis, det. M. S. Engel''. COMMENTS: These two, well-preserved individuals differ slightly in the shape of the head and particularly in the structure of me- Fig. 80. Frontal view of head of holotype female of Thaumastobombus andreniformis, new tatibial spur whereby the thickening of the species. Scale bar ϭ 0.5 mm. spur toward its apex present in the holotype of T. andreniformis (®g. 84) is apparently absent in both of these individuals. This spec- length, simple setae. Pubescence of mesos- imen also appears to have microscopic barbs cutum as described for vertex. Tegula with a on the sting (perhaps also present in true T. few, minute, appressed, simple setae. Scutel- andreniformis?). These differences are likely lar pubescence as on mesoscutum except se- not great enough to deserve speci®c status tae along posterior border elongate and plu- separated from T. andreniformis; however, I mose. Pleura with dense, long, plumose se- hesitate to place them immediately into T. tae, partially obscuring integument. Posterior andreniformis until more material of the ge- surface of metafemur with keirotrichiate nus is discovered. If these differences contin- zone on apical two-thirds; inner surface of ue to be upheld or are found to be congruent metatibia with keirotrichiate zone not elevat- with additional, yet undiscovered, characters, ed but with narrow glabrous posterior margin then speci®c status for this morph would be that is one-®fth width of keirotrichiate zone, warranted. keirotrichiate zone separated from rastellum MELIKERTINI, New Tribe and metatibial apex by glabrous zone that is as long as width of keirotrichiate zone. Terga TYPE GENUS: Melikertes Engel, 1998a. with sparse setal bands along apical margin, DIAGNOSIS: This group most closely re- setae short and with a few, minute branches. sembles species of the stingless bee tribe Me-

→ Figs. 81±84. Leg structures of holotype female of Thaumastobombus andreniformis, new species. 81. Outer surface of metatibia and metatarsus. 82. Strigil at protibia-probasitarsus junction. 83. Ventral, slightly oblique view of metatarsus and metatibia (thus, outer surface of metatibia is visible while inner surface of metabasitarsus is visible). 84. Magni®ed view of metatibial spur. Scale bars ϭ 0.5 mm (a ϭ ®g. 81; b ϭ ®g. 83; c ϭ ®g. 82). 2001 ENGEL: BALTIC AMBER BEES 113 114 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

TABLE 9 Hierarchical Classi®cation of Tribe ²Melikertini

Fig. 85. Forewing of holotype female of Thaumastobombus andreniformis, new species. Scale bar ϭ 1 mm. liponini. The general habitus of all species is Trigona-like. The melikertines differ from the Meliponini by the complete wing venation, presence of a single metatibial spur, presence of a supraalar carina, toothed claws, group of Baltic amber bees and specimens presence of an auricle, and presence of a seem to be relatively commonly encountered. sting. Table 9 summarizes the classi®cation of the DESCRIPTION: Small to moderate size (ca. tribe as I have outlined it herein. 3±8.5 mm long), slender, sparsely pubescent bees. Mandible without outer mandibular Key to Genera of Melikertini grooves. Labral width 3±4 times length. Clypeus gently convex and weakly protuber- 1. Clypeal protrusion absent (e.g., ®gs. 100, 105) ...... 2 ant in pro®le. Compound eyes bare. SupraaÈ- ± Clypeal protrusion present, i.e., base of clyp- lar carina present; scutellum broadly rounded eus produced into variously modi®ed tu- posteriorly and variously produced (ranging bercles, tubercle bending upward over fron- from projecting over metanotum and propo- to-clypeal portion of epistomal sulcus and deum to not projecting over metanotum). supraclypeal area, ending between antennal Claws of female with minute, inner tooth sockets (e.g., ®gs. 86±88, 93±98) ..... (®gs. 89, 90, 108); arolium strong and pre- ...... Succinapis, n. gen. sent (e.g., ®g. 108); single, reduced metati- 2. Scutellum bulging, overhanging metanotum bial spur present (®gs. 90, 102, 107); malus and propodeum; apical margins of meta- of strigilis with short anterior prong in ad- somal terga distinctly lighter than remainder of metasoma, thus metasoma appears dition to primary ventral velum; metabasitar- banded; anterior and posterior margins of sus with distinct auricle at base (®gs. 89, 90, metabasitarus distinctly converging toward 106, 107); metatibia without penicillum. Dis- apex (®g. 107) ...... 3 tal venation of forewing strong and present ± Scutellum not bulging, not overhanging me- (®gs. 91, 103, 109); marginal cell large and tanotum or propodeum (®g. 101); metaso- narrowly rounded at apex, slightly offset mal terga uniformly colored; anterior and from wing margin, feebly appendiculate, cell posterior margins of metabasitarsus ap- longer than distance from its apex to wing proximately parallel (®g. 102) ...... apex; pterostigma present and moderate size, ...... Melikertes Engel much longer than prestigma, r-rs arising near 3. Anterior margin of ®rst submarginal cell in- or just beyond midpoint, margin within mar- side marginal cell approximately equal to length of anterior margin of second sub- ginal cell convex; 1m-cu angled; hind wing marginal cell inside marginal cell (i.e., vein with distinct jugal lobe, lobe broadly and r-rs as long as immediately succeeding ab- deeply incised (®gs. 92, 104, 110); hamuli scissa of Rs) (®g. 109); basal vein con¯uent reduced; wing membrane without alar papil- with cu-a; compound eyes converging be- lae. Sting not reduced; apparently not barbed. low (®g. 105); F2 distinctly shorter than F3, COMMENTS: This is a particularly diverse F1 distinctly shorter than combined lengths 2001 ENGEL: BALTIC AMBER BEES 115

of F2±3 (®g. 105) ...... ± Clypeal protrusion extending dorsally above ...... Melissites, n. gen. level of antennal sockets by more than the ± Anterior margin of ®rst submarginal cell in- diameter of an antennal socket (®gs. 96± side marginal cell many times longer than 98) ...... S. proboscidea, n. sp. length of anterior margin of second sub- 2. Clypeal protrusion straight, apex not bent an- marginal cell inside marginal cell (i.e., vein teriorly, apex with short setae (®gs. 86±88); r-rs many times longer than immediately mesepisternum smooth ...... succeeding abscissa of Rs); basal vein con- ...... S. goeleti, n. sp. ¯uent with cu-a; compound eyes approxi- ± Clypeal protrusion bent anteriorly at apex, mately parallel; F2 approximately equal in apex with long setae (®gs. 93±95); mese- length to F3, F1 approximately equal to pisternum punctured ...... combined lengths of F2±3 ...... S. micheneri, n. sp...... Roussyana Manning Succinapis goeleti, new species Succinapis, new genus Figures 86±92 TYPE SPECIES: Succinapis proboscidea En- Plate 7d gel, new species. DIAGNOSIS: This genus is most similar in DIAGNOSIS: Succinapis goeleti is the most general habitus to Melikertes but differs by primitive species of the genus as it is pres- the presence of a basal clypeal protrusion. ently understood (see phylogenetic discus- DESCRIPTION: Malar space short, shorter sion below; ®g. 99). The species can be dis- than basal mandibular width. Epistomal sul- tinguished from all other Succinapis by the cus forming obtuse angle; clypeus with basal short clypeal protrusion that does not extend clypeal protrusion (i.e., base of clypeus above the level of the antennae by more than slightly extending outward and upward over the diameter of an antennal socket (®gs. 86± fronto-clypeal sulcus, typically covering su- 88), the greatly narrowed second submargin- praclypeal area and ending in a tubercle be- al cell (®g. 91), and the impunctate pleura, tween antennal sockets) (®gs. 86±88, 93±98). among other features. F1 longer than F2; F2 equal to F3. Inner mar- DESCRIPTION: Female. Total body length gins of compound eyes roughly parallel. Pre- 3.55 mm; forewing length 3.30 mm. Head occipital ridge rounded. Mesoscutal anterior wider than long (length 0.93 mm, width 1.23 border broadly rounded; tegula tear-drop mm). Clypeal protrusion short, not extending shaped; scutellum not bulging, not projecting dorsally above level of antennal sockets by over metanotum. Basal area of propodeum more than diameter of an antennal socket nearly horizontal, not declivitous. Keirotri- (®gs. 86±88), protrusion not bent anteriorly. chiate ®eld not elevated (®g. 90); metatibial Upper interorbital distance 0.92 mm; lower spur serrate or minutely ciliate; auricular bas- interorbital distance 0.82 mm. Interocellar ket sparse, setae short; rastellum strong and distance 0.27 mm; ocellocular distance 0.32 formed of stiff setae (®g. 90); metabasitarsus mm; median to lateral ocellus 0.08 mm. In- parallel-sided. Three submarginal cells (®g. tertegular distance 0.78 mm. Basal vein ba- 91). Metasomal terga not banded. sad cu-a by 2.5 times vein width; 1m-cu ba- ETYMOLOGY: The new genus-group name sad 2rs-m by ®ve times vein width; 2rs-m is a combination of the Latin words succi- distad 2m-cu by 1.5 times vein width; ®rst neus (meaning ``amber'') and apis (meaning submarginal cell shorter than second and ``bee''). The name is feminine. third combined; length of anterior border of COMMENTS: The peculiar clypeal protru- second submarginal cell one-tenth that of sion is a unique feature among the corbicu- posterior border (i.e., second submarginal late Apinae. At present the function of such cell strongly narrowed anteriorly); length of a structure in workers is illusive. posterior border of third submarginal cell 1.5 times that of anterior border, anterior border Key to Species of SUCCINAPIS seven times length of anterior border of sec- 1. Clypeal protrusion extending above level of ond submarginal cell; six distal hamuli, ar- antennal sockets by an antennal socket di- ranged in a single, evenly spaced series. ameter or less (®gs. 86±88, 93±95) .... 2 Clypeus impunctate and smooth. Face, 116 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 86±88. Head of holotype female of Succinapis goeleti, new species. 86. Frontal view. 87. Lateral view. 88. Frontodorsal, oblique view. Scale bar ϭ 0.5 mm. 2001 ENGEL: BALTIC AMBER BEES 117

Figs. 89±90. Metatibia and metatarsus of holotype female of Succinapis goeleti, new species. 89. Outer surface. 90. Inner surface. Scale bar ϭ 0.5 mm. vertex, and gena with sparse, minute punc- of vertex and gena as described for face. tures, integument between smooth. Pronotum Postgena with short, simple, erect setae. Pu- with sparse, faint, minute punctures, integu- bescence of pronotum as described for face. ment between smooth. Mesoscutum and scu- Mesoscutum with short, sparse, simple, erect tellum sculptured as on mesoscutum. Tegula setae. Scutellum with erect, long (2.5±4 OD) impunctate and smooth. Metanotum impunc- setae on posterior border, setae minutely plu- tate and faintly imbricate. Pleura impunctate mose. Pleural pubescence as described for and smooth. Propodeum glabrous. Metasoma face. Lateral surface of propodeum with pu- impunctate and faintly imbricate. bescence as described for face; basal area of Head, mesosoma, and metasoma black propodeum without pubescence. Inner sur- without maculations; legs dark brown. Wing face of metafemur and metatrochanter with- membrane hyaline; veins strong and dark out pubescence except apical sixth of meta- brown. femur with dense ®eld of keirotrichiae; inner Pubescence fuscous. Labrum with moder- surface of metatibia with keirotrichiate ®eld, ate-length, simple, erect setae scattered on ®eld separated by its width from metatibial surface. Clypeus with sparse, minute, sub- apex; corbicula bordered by long, minutely- erect, simple setae and short, simple, sub- plumose setae; metatarsus with simple, stout erect, anteriorly-directed setae on dorsal-fac- setae; seven comb rows on inner surface of ing surface of clypeal protrusion. Face with metabasitarsus. Metasomal terga with sparse, sparse, suberect, minute, simple setae. Setae simple, short, appressed setae, slightly more 118 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 91±92. Wings of holotype female of Succinapis goeleti, new species. 91. Forewing. 92. Hind wing. Scale bar ϭ 0.5 mm. numerous laterally; sterna with scattered, that one of these spectacular fossils bear his simple, erect (2.5±3 OD) setae. name. MATERIAL: Two specimens. Holotype. Fe- male, worker caste, B-JH 90 (AMNH) la- Succinapis micheneri, new species beled: ``Baltic amber: Eocene, Kaliningrad, Figures 93±95 Yantarny'' // ``Holotype, Succinapis goeleti Plate 7c Engel''. Paratype. Female, worker caste, B-W 162 Electrapis (Roussyana) palmnickenensis (Rous- sy); Zeuner and Manning, 1976: 233. [misiden- (AMNH) labeled: ``Baltic amber: Eocene, ti®cation] Kaliningrad, Yantarny'' // ``Paratype, Succi- napis goeleti Engel''. DIAGNOSIS: This species is similar to S. ETYMOLOGY: The speci®c epithet is a pat- goeleti in that the clypeal protrusion is rela- ronymic honoring Mr. Robert G. Goelet, tively short (not extending above the level of Chairman Emeritus of the AMNH Board of the antennae by more than the diameter of Trustees. Mr. Goelet has generously support- an antennal socket) but differs in that the ed my work at the AMNH, while at the same apex of the process is bent anteriorly (®g. time greatly augmenting the collection of liv- 93±95). Moreover, the second submarginal ing and amber-fossil insects. It is only ®tting cell is not as strongly narrowed anteriorly 2001 ENGEL: BALTIC AMBER BEES 119

(the anterior border is only one-fourth that of Pubescence generally whitish. Labrum the posterior border in S. micheneri by com- with moderate-length, simple, erect setae parison to approximately one-tenth in S. goe- scattered on integumental surface. Clypeus leti) and the pleura are distinctly punctured. without setae except moderate-length, sim- DESCRIPTION: Female. Total body length ple, suberect, anteriorly-directed setae on 3.68 mm; forewing length 3.05 mm. Head dorsal-facing surface of clypeal protrusion. wider than long (length 1.08 mm, width 1.13 Face with sparse, suberect, short, simple se- mm). Clypeal protrusion short, not extending tae, setae more dense in lower paraocular dorsally above level of antennal sockets by area but not obscuring integument. Setae of more than diameter of an antennal socket, vertex and gena as described for face except protrusion strongly bent anteriorly (®gs. 93± minute. Postgena with short, simple, erect se- 95). Upper interorbital distance 0.83 mm; tae. Pubescence of pronotum as described for lower interorbital distance 0.77 mm. Intero- face except setae of dorsal surface restricted cellar distance 0.25 mm; ocellocular distance to posterior border and minute. Mesoscutum 0.27 mm; median to lateral ocellus 0.07 mm. with short, sparse, simple, erect setae. Scu- Intertegular distance 0.75 mm. Basal vein ba- tellum with erect, long (1±3 OD) setae on sad cu-a by 1.5 times vein width; 1m-cu bi- posterior quarter, setae each with several mi- secting second submarginal cell; 2rs-m distad nute branches and slightly fuscous. Hypoe- 2m-cu by two times vein width; ®rst sub- pimeral area without setae; remainder of marginal cell shorter than second and third pleura with pubescence as described for face. combined; length of anterior border of sec- Lateral surface of propodeum with pubes- ond submarginal cell one-fourth that of pos- cence as described for face; basal area of pro- terior border; length of posterior border of podeum without setae. Inner surface of me- third submarginal cell 1.5 times that of an- tafemur and metatrochanter without pubes- terior border, anterior border twice as long as cence except apical quarter of metafemur that of second submarginal cell; six distal with dense ®eld of keirotrichiae; inner sur- hamuli, arranged in a single, evenly spaced face of metatibia mostly covered by ®eld of series. keirotrichiae, ®eld separated from metatibial Clypeus impunctate and smooth. Scape apex by length equivalent to its own width; with sparse, minute punctures, integument corbicula bordered by long, minutely-plu- between smooth. Face with minute punctures mose setae; metatarsus with simple, stout se- separated by 2±4 times a puncture width, in- tae; six comb rows on inner surface of me- tegument between smooth. Sculpturing of tabasitarsus. Metasomal terga with scattered, vertex and gena as described for face. Post- simple, short, appressed setae, sparse on cen- gena impunctate and smooth. Pronotum with tral discs; sterna with scattered, simple, sub- minute punctures separated by a puncture erect setae that are short on S1±2 (0.5±1 OD) width except medially punctures faint, integ- then progressively longer on more apical ument between smooth. Mesoscutum with sterna (reaching 2.5 OD by S5). faint, sparse, minute punctures, integument MATERIAL: Twenty-one specimens. Holo- between smooth. Scutellum sculptured as on type. Female, worker caste, B-JH 103 mesoscutum. Tegula with minute, sparse, (AMNH) labeled: ``Baltic amber: Eocene, faint punctures, integument between smooth. Kaliningrad, Yantarny'' // ``Holotype, Suc- Pleura with small punctures separated by 1± cinapis micheneri Engel''. 2 times a puncture width except hypoepi- Paratype. Female, worker caste, B-W 154 meral area impunctate, integument otherwise (AMNH) labeled: ``Baltic amber: Eocene, smooth between punctures. Sculpturing of Kaliningrad, Yantarny'' // ``Paratype, Succi- propodeal lateral surface as described for napis micheneri Engel''. mesepisternum; basal area of propodeum gla- Paratypes. Five females, worker caste brous. Metasomal terga smooth and impunc- (CFEG) labeled: ``Paratype, Succinapis tate; sterna ®nely imbricate and impunctate. micheneri Engel''. Color, where evident, brown, without mac- Paratype. Female, worker caste, Nr. 3709 ulations. Wing membrane hyaline; veins (CCGG) labeled: ``Paratype, Succinapis strong and brown. micheneri Engel''. 120 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 93±95. Head of holotype female of Succinapis micheneri, new species. 93. Fronal view. 94. Ventrolateral, oblique view. 95. Dorsal view. Scale bars ϭ 0.5 mm (a ϭ ®g. 93; b ϭ ®gs. 94, 95).

Paratypes. Eleven females, worker caste (GPUH) labeled: ``Nr. 80 (Scheele)'' // ``Erd- (eight complete, three partials), Nr. 3±17 biene, Apidae, genus Andrena?'' // ``Para- (CGHG) labeled: ``Nr. 3±17'' // ``Paratype, type, Succinapis micheneri Engel''. This is Succinapis micheneri Engel''. the specimen misidenti®ed as Electrapis Paratype. Female, worker caste, Nr. 80 (Roussyana) palmnickenensis by Zeuner and 2001 ENGEL: BALTIC AMBER BEES 121

Manning (1976: see Comments under Rous- tures becoming gradually more faint and syana palmnickenensis, below). more sparse toward vertex and on gena. Paratype. Female, worker caste (PMUZ) Pronotum with minute punctures separated labeled: ``Paratype, Succinapis micheneri by a puncture width except medially punc- Engel''. tures faint, integument between smooth. Me- ETYMOLOGY: The speci®c epithet is a pat- soscutum mostly obscured by a thin layer of ronymic honoring my mentor and friend, Dr. Schimmel; where evident, integument with Charles D. Michener, world's authority on faint, minute punctures separated by 1±2 bees. times a puncture width, integument between smooth. Scutellum sculptured as on mesos- Succinapis proboscidea, new species cutum. Tegula with minute, faint punctures Figures 96±98 on outer half, otherwise integument smooth. Plate 7b Metanotum obscured from view by fracture planes and ¯ows from scutellum. Pleura with DIAGNOSIS: This is the most distinctive of small punctures separated by 1±2 times a all the Succinapis species. The grossly en- puncture width, becoming faint on central larged clypeal protrusion that is both bent an- disc of mesepisternum and separated by 2±4 teriorly as well as extending above the level times a puncture width, and hypoepimeral of the antennae by more than the diameter of area with faint and exceedingly sparse punc- an antennal socket (®gs. 96±98) serves to im- tures, integument of pleura smooth between mediately differentiate S. proboscidea from punctures. Propodeal lateral surface with mi- both S. micheneri and S. goeleti. nute, faint punctures separated by 2±3 times DESCRIPTION: Female. Total body length a puncture width, integument between 4.15 mm; forewing length 3.55 mm. Head smooth; basal area of propodeum glabrous. wider than long (length 1.34 mm, width 1.43 Metasoma faintly imbricate and impunctate. mm). Clypeal protrusion greatly enlarged, Color, where evident, dark brown, without extending above level of antennal sockets by maculations. Wing membrane hyaline; veins more than diameter of an antennal socket, strong and dark brown. protrusion bent anteriorly (®gs. 96±98). Up- Pubescence generally whitish. Labrum per interorbital distance 0.98 mm; lower in- with moderate-length, simple, erect setae terorbital distance 0.93 mm. Interocellar dis- widely scattered over surface. Clypeus with tance 0.40 mm; ocellocular distance 0.30 minute, suberect, simple setae restricted to mm; median to lateral ocellus 0.10 mm. In- lateral borders and short, simple, suberect, tertegular distance 0.98 mm. Basal vein ba- anteriorly-directed setae on dorsal-facing sad cu-a by vein width; 1m-cu bisecting sec- surface of clypeal protrusion. Face with ond submarginal cell; 2rs-m distad 2m-cu by sparse, suberect, minute, simple setae, such two times vein width; ®rst submarginal cell setae becoming slightly more dense in lower shorter than second and third combined; paraocular area near clypeal lateral border. length of anterior border of second submar- Setae of vertex and gena as described for ginal cell one-fourth that of posterior border; face. Postgena with short, simple, erect setae. length of posterior border of third submar- Pubescence of pronotum as described for ginal cell 1.75 times that of anterior border, face except setae of dorsal surface restricted anterior border two times length of that of to posterior border. Mesoscutum with short, second submarginal cell; six distal hamuli, sparse, simple, erect setae evident through arranged in a single, evenly spaced series. thin layer of Schimmel. Scutellum with erect, Clypeus with sparse, minute punctures, in- long (1±3 OD) setae on posterior third, setae tegument between smooth; anterior-facing each with several minute branches. Hypoe- surface of clypeal protrusion with a few pimeral area without setae; remainder of weak longitudinal striae. Scape with minute pleura with pubescence as described for face. punctures separated by a puncture width, in- Lateral surface of propodeum with pubes- tegument between smooth. Face with minute cence as described for face; basal area of pro- punctures separated by 1±2 times a puncture podeum without setae. Inner surface of me- width, integument between smooth; punc- tafemur and metatrochanter without pubes- 122 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 96±98. Head of holotype female of Succinapis proboscidea, new species. 96. Frontal view. 97. Oblique, lateral view. 98. Dorsal view. Scale bar ϭ 0.5 mm. 2001 ENGEL: BALTIC AMBER BEES 123 cence except apical quarter of metafemur applies if the polarities are reversed for each with dense ®eld of keirotrichiae; inner sur- of the discussed characters. Fortunately, the face of metatibia with keirotrichiate zone; sculpturing of the mesepisternum provides corbicula bordered by long, minutely-plu- some information that can be compared to mose setae; metatarsus with simple, stout se- the related melikertine genera and for polar- tae; six comb rows on inner surface of me- izing the species in Succinapis. The mese- tabasitarsus. Metasomal terga with scattered, pisternum in all species of Melikertes is simple, short, appressed setae, sparse on cen- smooth and impunctate. Within Succinapis tral discs; sterna with scattered, simple, erect, smooth pleural integument is only found in slightly fuscous setae. S. goeleti, while both S. micheneri and S. MATERIAL: Three specimens. Holotype. proboscidea have punctured mesepisterna. It Female, worker caste, B-JH 96 (AMNH) la- would therefore appear that S. goeleti is the beled: ``Baltic amber: Eocene, Kaliningrad, most plesiomorphic species of the genus by Yantarny'' // ``Holotype, Succinapis probos- comparison to Melikertes. This hierarchy po- cidea Engel''. larizes the clypeal protrusion morphology Paratype. Female, worker caste, B-JH 99 (®g. 99). The shortened clypeal protrusion (AMNH) labeled: ``Baltic amber: Eocene, that does not project more than an antennal Kaliningrad, Yantarny'' // ``Paratype, Succi- socket diameter above the antennal sockets napis proboscidea Engel''. observed in S. goeleti and S. micheneri is Paratype. Female, worker caste, Nr. 10 presumably plesiomorphic. The apical bend (CSUL) labeled: ``Paratype, Succinapis pro- of the clypeal protrusion is an apomorphic boscidea Engel''. feature uniting S. micheneri and S. probos- ETYMOLOGY: The speci®c epithet is de- cidea, while the greatly enlarged process is rived from the Greek word proboskidos, re- an autapomorphy of S. proboscidea (®g. 99). ferring to the trunk of an elephant, and is a reference to the structure of the large clypeal Genus Melikertes Engel, status novus protrusion of this species. Electrapis (Melikertes) Engel, 1998a: 95. Type species: Electrapis (Melikertes) stilbonota En- Internal Phylogeny of Succinapis gel, 1998a, original designation.

The morphology of the clypeal protrusion DIAGNOSIS: This genus is similar to Suc- suggests a hierarchy of relationship among cinapis but lacks the basal clypeal protrusion. the species of Succinapis (®g. 99). By com- DESCRIPTION: Malar space short, shorter parison to other melikertine genera as out- than basal mandibular width. Epistomal sul- groups it is possible to build a preliminary cus forming obtuse angle or nearly linear cladistic hypothesis for the three known Suc- (e.g., M. stilbonotus: ®g. 100); clypeus with- cinapis species. The presence of the clypeal out basal clypeal protrusion (®g. 100). F1 protrusion is a unique apomorphy among the longer than F2; F2 equal to F3. Inner mar- corbiculate Apinae and nicely serves to sup- gins of compound eyes roughly parallel. Pre- port the monophyly of the genus. The polar- occipital ridge rounded or weakly carinate. ity of the different morphotypes of clypeal Mesoscutal anterior border broadly rounded; protrusions is impossible to determine in iso- tegula tear-drop shaped; scutellum not bulg- lation from other characters as there is no ing, not projecting over metanotum (®g. corresponding structure in the outgroups. 101). Basal area of propodeum nearly hori- The apically bent clypeal protrusions of S. zontal, not declivitous. Keirotrichiate ®eld micheneri and S. proboscidea could be inter- not elevated (®g. 102); metatibial spur serrate preted as plesiomorphic with S. goeleti and or minutely ciliate; auricular basket sparse, S. micheneri perhaps clustered on the basis setae short; rastellum strong and formed of of shortened protrusion and S. goeleti auta- stiff setae (®g. 102); metabasitarsus parallel- pomorphic for a straight process, or if the sided (®g. 102). Three submarginal cells (®g. polarity of the protrusion's size is removed, 103). Metasomal terga not banded. then our three-taxon statement collapses to a COMMENTS: I previously (Engel, 1998a) er- trichotomy. The same scenario of dif®culties roneously reported an absence of metatibial 124 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 99. Phylogeny of Succinapis based on morphology of the clypeal protrusion. spurs for Melikertes. Subsequent study of the 2. Apical margin of clypeus unmodi®ed, type material for M. stilbonotus as well as straight, and ¯at as on remainder of clypeus newly discovered material of other meliker- ...... M. stilbonotus (Engel) tine bees has revealed a single, reduced me- ± Apical margin of clypeus strongly projecting tatibial spur. This structure is dif®cult to ob- outward from face with deep medial cleft, remainder of clypeus relatively ¯at .... serve in the holotype and paratype of M. stil- ...... M. clypeatus, n. sp. bonotus but is distinctly present (®g. 102).

Key to Species of MELIKERTES Melikertes proavus (Menge), new combination 1. Tegula without posterior lamella, oval or tear- drop shaped; body size small (ca. 3±4.5 Apis proava Menge, 1856: 26. mm) ...... 2 Electrapis (Roussyana) proava (Menge); Zeuner ± Tegula with short, posterior lamella; body and Manning, 1976: 236. size moderate (ca. 8 mm) ...... Trigona (Roussyana) proava (Menge); Kerr and ...... M. proavus (Menge) Cunha, 1976: 39. 2001 ENGEL: BALTIC AMBER BEES 125

Figs. 100±101. Holotype female of Melikertes stilbonotus (Engel). 100. Frontal view of head. 101. Dorsal view. Scale bars ϭ 0.5 mm (a ϭ ®g. 101; b ϭ ®g. 100).

Electrapis (Melikertes) proava (Menge); Engel, anterior border of second submarginal cell; 1998a: 95. six distal hamuli, arranged in a single, evenly DIAGNOSIS: This is the largest and least un- spaced series. derstood species of Melikertes (simply owing Integument of head, mesosoma, and me- to the fact that the two specimens known are tasoma apparently smooth and impunctate in poor condition by comparison to material except metanotum rugulose and sterna im- of other species). The species is exceptional bricate. for its large size compared to other Meliker- Coloration not well preserved, apparently tes. dark brown to black and shining, without DESCRIPTION: Female. Total body length maculations. Wing membrane hyaline; veins 8.30 mm; forewing length 6.0 mm. Apical strong and dark brown. margin of clypeus straight, not bent apically. Pubescence generally pale. Setae of face Intertegular distance 2.15 mm. Tegula with and vertex widely scattered, simple, and short, posterior lamella. Basal vein basad cu- short. Gena with simple, short, suberect setae a by two times vein width; 1m-cu bisecting very sparsely scattered; postgena with long, second submarginal cell; 2rs-m distad 2m-cu; simple setae sparsely scattered over integu- ®rst submarginal cell only slightly shorter ment. Pronotal collar without pubescence; than second and third combined; second sub- pronotal border with mesoscutum with short, marginal cell narrowed anteriorly, not very simple setae; lateral surface with similar mi- strongly so; length of anterior border of third nute setae. Mesoscutum with scattered, mi- submarginal cell half of that of posterior bor- nute setae, more sparsely scattered on central der, anterior border about as long as that of disc. Pubescence of scutellum as described 126 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Paralectotype, Transf. [transferred] from Zool. Dept. [Zoology Department], 15 Dec. [December] 1904, (In. 18757), 92±14 [74?]'' // ``Neotype, Apis proava Menge, 1856, desig. ICZN (M. S. Engel)''. Formerly the paralectotype designated by Zeuner and Man- ning (1976: 236; see Comments below); designated as neotype by ICZN Opinion Nr. 1964 (ICZN, 2000). The amber piece is set into Canadian balsam and mounted onto a microscope slide. Non-type. Female, worker caste, In. 43592 (BMNH) labeled: ``In. 43592, E. proava, Lectotype'' // ``M. proava? (Menge), non-type, desig. ICZN (M. S. Engel)'' // ``Melikertes proavus? (Menge), det. M. S. Engel''. Formerly lectotype; designation by Zeuner and Manning (1976: 236; see Com- ments below). This individual is assigned to M. proavus with great hesitation owing to its extremely poor condition. Zeuner and Man- ning (1976), who examined the specimen before it was damaged, considered it to be conspeci®c with the above specimen. COMMENTS: The type designations of Zeu- ner and Manning (1976) have been suppressed owing to the poor condition of their chosen lectotype (Engel, 1999a; ICZN, Fig. 102. Inner surface of metatibia and meta- 2000). tarsus of holotype female of Melikertes stilbonotus (Engel). Melikertes stilbonotus (Engel), new combination Figures 100±104 for mesoscutum. Hypoepimeral area without Electrapis (Melikertes) stilbonota Engel, 1998a: pubescence; remainder of mesepisternum 95. with widely scattered, minute setae. Basal area and posterior surface of propodeum DIAGNOSIS: Refer to diagnosis for M. cly- without pubescence. Inner surface of meta- peatus (see below). femur and metatrochanter without pubes- DESCRIPTION: Female. Total body length cence except apical quarter of metafemur 3.76 mm; forewing length 3.00 mm. Head with dense ®eld of keirotrichiae; inner sur- wider than long (length 1.12, width 1.32: face of metatibia with keirotrichiate zone. T1 measurements from paratype). Upper inter- without pubescence on central disc, a few, orbital distance 0.86 mm; lower interorbital simple setae on lateral borders; pubescence distance 0.82 mm (both metrics from para- of T2±T6 as described for T1 except a few type). Apical margin of clypeus straight, not simple setae on posterolateral borders; sterna bent apically. Intertegular distance 0.82 mm. with sparse, simple, subappressed setae. Basal vein basad cu-a by two times vein MATERIAL: Two specimens. Neotype. Fe- width; 1m-cu bisecting second submarginal male, worker caste, Nr. 13781 (BMNH) la- cell; 2rs-m distad 2m-cu by 1.5 times vein beled: ``No. 13781, Bee, Museum Stantien & width; ®rst submarginal cell shorter than sec- Becker'' // ``515, Dr. R. Klebs, 92±14 [74?]'' ond and third combined; length of anterior // ``XII B781 [on the amber block]'' // ``Elec- border of second submarginal cell one-tenth trapis proava (Menge), Amber, East Prussia, that of posterior border (i.e., second submar- 2001 ENGEL: BALTIC AMBER BEES 127

Figs. 103±104. Wings of holotype female of Melikertes stilbonotus (Engel). 103. Forewing. 104. Hind wing. Scale bar ϭ 0.5 mm. ginal cell strongly narrowed anteriorly); scattered over integument. Pronotal collar length of anterior border of third submarginal without pubescence; pronotal border with cell half of that of posterior border, just over mesoscutum with short, simple setae; lateral three times length of anterior border of sec- surface with similar minute setae, such setae ond submarginal cell; six distal hamuli, ar- appressed but not obscuring integument. Me- ranged in a single, evenly spaced series; cu- soscutum with scattered, simple setae, more a of hind wing orthogonal to MϩCu. sparsely scattered and shorter on central disc, Integument of head, mesosoma, and me- those setae on anterolateral borders with a tasoma smooth and impunctate except me- few short branches. Pubescence of scutellum tanotum rugulose. S3±6 weakly and sparsely as described for mesoscutum except longer nodulate, integument between smooth. and restricted to posterior border. Metanotum Coloration not well preserved, apparently with dense, minute, simple setae, not ob- dark brown to black and shining, without scuring integument. Hypoepimeral area with- maculations. Wing membrane hyaline; veins out pubescence; remainder of mesepisternum strong and dark brown. with scattered, simple setae, such setae grad- Pubescence generally pale. Setae of face ually become longer ventrally; central disc, widely scattered, simple, and short; such however, without pubescence. Basal area and hairs becoming gradually longer toward ver- posterior surface of propodeum without pu- tex. Gena with simple, short, suberect setae; bescence; lateral surface with scattered, long, postgena with long, simple setae sparsely simple setae intermixed with shorter, ap- 128 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 pressed setae, such setae partially obscuring ever, is immediately recognizable by the pe- integument. Pubescence of legs generally culiar modi®cation of the clypeal apical mar- simple and scattered except inner surfaces of gin that is strongly ¯exed forward below the mesotrochanter and mesofemur without pu- level of the lower tangent of the compound bescence and outer surface of mesotibia with eyes. Moreover, the projecting portion of the dense, branched setae; inner surface of me- clypeal apical margin possesses a strong metafemur and metatrochanter without pubes- dial cleft. cence except apical quarter of metafemur DESCRIPTION: Female. Total body length with dense ®eld of keirotrichiae; inner sur- 3.10 mm; forewing length 2.65 mm. Head face of metatibia with keirotrichiate zone; wider than long (length 1.02 mm, width 1.22 eight comb rows on inner surface of meta- mm). Upper interorbital distance 0.83 mm; basitarsus, each composed of stiff, elongate, lower interorbital distance 0.75 mm. Intero- simple setae; outer surface with scattered, cellar distance 0.23 mm; ocellocular distance long, simple setae. T1 without pubescence on 0.28 mm; median to lateral ocellus 0.07 mm. central disc, a few, simple setae on lateral Apical margin of clypeus strongly bent api- borders; pubescence of T2 as described for cally, with distinct medial cleft. Intertegular T1 except a few simple setae on posterolat- distance 0.83 mm. Basal vein basad cu-a by eral borders; T3±6 with simple setae longer two times vein width; 1rs-m distad 1m-cu by than those of T1±2, sparsely scattered over six times vein width; 2rs-m distad 2m-cu by central disc, more concentrated on lateral three times vein width; ®rst submarginal cell margins; sterna with sparsely scattered, sim- shorter than second and third combined; ple setae. length of anterior border of second submar- MATERIAL: Five specimens. Holotype. Fe- ginal cell one-third that of posterior border; male, worker caste, In. 17778 (BMNH). The length of anterior border of third submarginal specimen bears labels reading ``Holotype, cell half of that of posterior border, twice Electrapis stilbonota, desig. M. S. Engel [red length of anterior border of second submar- label]'' // ``Amber Inclusa, Hymenoptera, In. ginal cell; ®ve distal hamuli, arranged in a 17778, Samland, No. 67 [white label]''. Am- single, evenly spaced series. ber piece preserved in Canadian balsam on a Integument of head, mesosoma, and me- slide mount. tasoma smooth and impunctate. Paratype. Female, worker caste, In. 17778 Coloration not preserved. Wing membrane (BMNH); same block of amber as holotype. hyaline; veins strong and brown. Paratype total body length 3.72 mm; fore- Pubescence generally pale. Setae of face wing length 3.16 mm. Refer to Engel sparse, simple, suberect, and short, although (1998a) for more measurements. such setae becoming erect on vertex. Meso- Non-type. Female, worker caste, B-JH 76 scutum with sparse, simple, short setae. Pu- (AMNH) labeled: ``Baltic amber: Eocene, bescence of scutellum as described for me- Kaliningrad, Yantarny'' // ''Melikertes stil- soscutum except longer on posterior border. bonotus (Engel), det. M. S. Engel''. Pleura with sparse, simple, short setae. Pu- Non-type. Female, worker caste, B-JH 82 bescence of legs generally simple and scat- (AMNH) labeled: ``Baltic amber: Eocene, tered except inner surfaces of mesotrochanter Kaliningrad, Yantarny'' // ``Melikertes stil- and mesofemur without pubescence and out- bonotus (Engel), det. M. S. Engel''. er surface of mesotibia with dense, branched Non-type. Female, worker caste, Nr. 63 setae; inner surface of metafemur and meta- (CJDL) labeled: ``Nr. 63'' // ``Melikertes stil- trochanter without pubescence except apical bonotus (Engel), det. M. S. Engel''. quarter of metafemur with dense ®eld of keirotrichiae; inner surface of metatibia with Melikertes clypeatus, new species keirotrichiate zone; comb rows on inner sur- Plate 7a face of metabasitarsus, each composed of stiff, elongate, simple setae; outer surface DIAGNOSIS: This species is most similar to with scattered, long, simple setae. Terga and M. stilbonotus, the two species looking re- sterna with exceedingly sparse, minute, sim- markably similar. Melikertes clypeatus, how- ple, appressed or subappressed setae. 2001 ENGEL: BALTIC AMBER BEES 129

MATERIAL: Holotype. Female, worker caste, B-JH 77 (AMNH) labeled: ``Baltic amber: Eocene, Kaliningrad, Yantarny'' // ``Holotype, Melikertes clypeatus Engel''. The only known specimen has a great deal of Schimmel on the mesosoma that entirely obscures the propodeum and metanotum. The scutellum, mesoscutum, tegula, and pleura can be seen with some dif®culty. The posterior portion of the head is also covered with some Schimmel, as are lateral portions of T1. ETYMOLOGY: The speci®c epithet is a reference to the modi®ed apical margin of the clypeus.

Melissites, new genus

TYPE SPECIES: Melissites trigona Engel, new species. DIAGNOSIS: See Diagnosis for Roussyana (below). DESCRIPTION: Malar space short, shorter than basal mandibular width (®g. 105). Ep- Fig. 105. Frontal view of holotype female istomal sulcus forming obtuse angle (®g. head of Melissites trigona, new species. Scale bar 105); clypeus without basal clypeal protru- ϭ 0.5 mm. sion. F1 longer than F2; F2 shorter than F3. Compound eyes strongly converging below and emarginate (®g. 105). Preoccipital ridge wider than long (length 1.25 mm, width 1.53 rounded. Mesoscutal anterior border broadly mm). Upper interorbital distance 0.97 mm; rounded; tegula oval; scutellum bulging, pro- lower interorbital distance 0.73 mm. Intero- jecting over metanotum and basal area of cellar distance 0.37 mm; ocellocular distance propodeum. Basal area of propodeum decliv- 0.22 mm; median to lateral ocellus 0.12 mm. itous. Keirotrichiate ®eld not elevated (®g. Intertegular distance 1.00 mm. Basal vein 107); metatibial spur ciliate; auricular basket con¯uent with cu-a; 1rs-m distad 1m-cu by sparse, setae short (®g. 106); rastellum strong eight times vein width; 2rs-m distad 2m-cu and formed of stiff setae; lateral margins of by 1.5 times vein width; ®rst submarginal metabasitarsus converging toward apex (®gs. cell shorter than combined lengths of second 106, 107). Three submarginal cells; anterior and third submarginal cells; length of pos- border of second submarginal cell as long as terior border of second submarginal cell r-rs (®g. 109). Metasomal terga banded. slightly less than twice anterior border; ETYMOLOGY: The new genus-group name length of anterior border of third submarginal is a combination of melissa (Greek, meaning cell three-quarters that of posterior border, ``bee'') and the suf®x -ites (Greek, meaning 1.25 times length of anterior border of sec- ``nature of'' or ``likeness'', a common suf®x ond submarginal cell; six distal hamuli ar- for fossil genera). The name is feminine. ranged in a single, evenly spaced series (®g. Melissites trigona, new species 110). Figures 105±110 Integument of head and mesosoma smooth Plate 6d and impunctate. Terga and sterna imbricate and impunctate. DIAGNOSIS: As for the genus (see above). Head and mesosoma black. Antennae, DESCRIPTION: Female. Total body length legs, and metasoma dark brown except apical 4.22 mm; forewing length 4.00 mm. Head margins of terga light brown to pale yellow. 130 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Figs. 106±108. Leg structures of holotype female of Melissites trigona, new species. 106. Outer surface of metatibia and metabasitarsus. 107. Inner surface of metatibia and metabasitarsus. 108. Claw and arolium. Scale bar ϭ 0.5 mm (®gs. 106, 107); 0.25 mm (®g. 108).

Wing membrane hyaline; veins strong and without pubescence and outer surface of me- dark brown. sotibia with dense, branched setae; inner sur- Pubescence lightly infuscated. Setae of face of metafemur and metatrochanter with- face widely scattered, simple, and short; such out pubescence except apical quarter of me- setae longer on vertex. Gena with simple, tafemur with dense ®eld of keirotrichiae; in- short, appressed setae; postgena with long, ner surface of metatibia with keirotrichiate simple setae sparsely scattered. Mesoscutum zone; corbicular setae simple; seven comb with sparse, simple setae, more sparsely scat- rows on inner surface of metabasitarsus, each tered and shorter on central disc. Pubescence composed of stiff, elongate, simple setae; of scutellum as described for mesoscutum outer surface with scattered, long, simple se- except two or more times longer, plumose, tae. Terga and sterna with short, simple, and dense on posterior half. Metanotum without pubescence. Hypoepimeral area sparse setae. without pubescence; remainder of mesepi- MATERIAL: One specimen. Holotype. Fe- sternum and metepisternum with scattered, male, worker caste, B-JH 102 (AMNH) la- simple, long setae. Basal area and posterior beled: ``Baltic amber: Eocene, Kaliningrad, surface of propodeum without pubescence; Yantarny'' // ``Holotype, Melissites trigona lateral surface with scattered, minute, sub- Engel''. erect, simple setae. Pubescence of legs gen- ETYMOLOGY: The speci®c epithet is taken erally simple and scattered except inner sur- (as a noun in apposition) from the genus- faces of mesotrochanter and mesofemur group name Trigona (Meliponini) and is a 2001 ENGEL: BALTIC AMBER BEES 131

Figs. 109±110. Wings of holotype female of Melissites trigona, new species. 109. Forewing. 110. Hind wing. Scale bars ϭ 1mm(aϭ ®g. 109; b ϭ ®g. 110). reference to the overall, super®cial resem- basal clypeal protrusion. F1 longer than F2; blance of this species to some stingless bees. F2 equal to F3. Inner margins of compound eyes roughly parallel. Preoccipital ridge Genus Roussyana Manning, status novus rounded. Mesoscutal anterior border broadly Electrapis (Roussyana) Manning, 1960: 306. rounded; tegula oval; scutellum bulging, pro- Type species: Apis palmnickenensis Roussy, jecting over metanotum and basal area of 1937, original designation. Zeuner and Man- propodeum. Basal area of propodeum decliv- ning, 1976: 233. itous. Keirotrichiate ®eld not elevated; me- Russyana Petrov, 1992: 361. Lapsus calami. tatibial spur serrate; auricular basket sparse, DIAGNOSIS: Roussyana most closely re- setae short; rastellum strong and formed of sembles Melissites; both genera have the dis- stiff setae; lateral margins of metabasitarsus tinctive banding of the metasoma owing to converging toward apex. Three submarginal the apical margins of the terga being very cells; anterior border of second submarginal pale brown in comparison to the remainder cell much shorter than r-rs. Metasomal terga of the terga, which are dark brown. The ge- banded. nus can be separated from Melissites by the strongly narrowed second submarginal cell, Roussyana palmnickenensis (Roussy) basal vein basal to cu-a, and the approxi- Apis palmnickenensis Roussy, 1937: 66. mately parallel compound eyes. Electrapis (Roussyana) palmnickenensis (Rous- DESCRIPTION: Malar space short, shorter sy); Manning, 1960: 306. Zeuner and Manning, than basal mandibular width. Epistomal sul- 1976: 233 [misidenti®cation: see Succinapis cus forming obtuse angle; clypeus without micheneri, above] 132 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Electrapis minuta Kelner-Pillault, 1970a: 16. NEW stiff, elongate, simple setae; outer surface SYNONYMY. with scattered, long, simple setae. T1±5 with Trigona (Roussyana) palmnickenensis (Roussy); sparse, minute, suberect, simple setae; T6 Kerr and Cunha, 1976: 39. with numerous, short, simple setae uniformly Roussyana palmuickenensis Petrov, 1992: 361. covering surface; sterna with sparsely scat- Lapsus calami. tered, short, simple setae and with dense, DIAGNOSIS: As for the genus (see above). subapical rows of long setae. DESCRIPTION: Female. Total body length MATERIAL: Three specimens. Neotype 3.08 mm; forewing length 2.3 mm. Head lon- (palmnickenensis; here designated). Fe- ger than wide (length 0.93 mm, width 0.88 male, worker caste, NB.I.1945 [Berendt Col- mm). Mandible with a single small tooth on lection] (ZMHB) labeled: ``Neotype, Apis upper one-®fth of apical margin. Intertegular palmnickenensis Roussy, desig. M. S. En- distance 0.82 mm. Basal vein basad cu-a by gel'' // ``50a'' [Berendt handwriting] // two times vein width; 1rs-m distad 1m-cu by ``NB.I.1945''. The types for Roussy's species seven times vein width; 2rs-m distad 2m-cu were in his private collection. A diligent by two times vein width; ®rst submarginal search for their whereabouts failed to locate cell shorter than combined lengths of second them. I have thus here designated a neotype and third submarginal cells; second submar- for the species. The limited description Rous- ginal cell strongly narrowed anteriorly, an- sy (1937) presented for the species, however, terior border shorter than r-rs; anterior border best agrees to Kelner-Pillault's specimens of third submarginal cell approximately nine among all of the corbiculate bees in Baltic times longer than anterior border of second amber. I, therefore, believe Roussy's and submarginal cell; six distal hamuli arranged Kelner-Pillault's specimens to be conspeci®c in a single, evenly spaced series. and have chosen the most completely pre- Head and mesosoma smooth and impunc- served of the two individuals in the piece to tate except corbicula ®nely imbricate. Terga serve as the neotype for Apis palmnickenen- and sterna ®nely and faintly imbricate except sis Roussy as well as the lectotype for Elec- lighter apical margins of terga glabrous. trapis minuta Kelner-Pillault. The two para- Head and mesosoma black. Antennae, lectotype individuals (designated below) are legs, tegulae, and metasoma dark brown ex- clustered together on one end of the piece, cept apical margins of terga light brown. while the neotype/lectotype is alone on the Pubescence generally pale. Labrum with opposite end. several, long, simple setae widely scattered. Lectotype (minuta; here designated). Fe- Setae of face widely scattered, simple, and male, worker caste, NB.I.1945 (ZMHB) la- short, although setae becoming slightly lon- beled: ``Lectotype, Electrapis minuta Kelner- ger on vertex. Mesoscutum with scattered, Pillault, desig. M. S. Engel'' // ``Electrapis long, simple setae. Pubescence of scutellum minuta S.K.P., syntypes, S. Kelner-Pillault, as described for mesoscutum except some- det.'' [Kelner-Pillault handwriting] // ``Rous- what longer. Metanotum without pubescence. syana minuta (Kelner-Pillault), det. M. S. Hypoepimeral area without pubescence; re- Engel, 1999''. Since this is the same speci- mainder of mesepisternum with scattered, men designated above as the neotype for A. simple setae, although particularly sparse on palmnickenensis, the remaining labels are central disc; setae slightly longer ventrally. identical to those listed above for A. palm- Basal area of propodeum without pubes- nickenensis (refer to preceding paragraph). cence. Pubescence of legs generally simple Paralectotypes (minuta; here designat- and scattered except inner surfaces of me- ed). Two females, worker caste, NB.I.1945 sotrochanter and mesofemur without pubes- (ZMHB): these specimens are in the same cence and outer surface of mesotibia with amber block as the lectotype and bear the dense, branched setae; inner surface of me- same labels. They are distinguished from the tafemur and metatrochanter without pubes- lectotype by the poorer state of preservation, cence; inner surface of metatibia with kei- both are heavily covered in Schimmel and rotrichiate zone; distinct comb rows on inner surrounded by numerous small fracture surface of metabasitarsus, each composed of planes. 2001 ENGEL: BALTIC AMBER BEES 133

COMMENTS: The specimen ®gured as a non-type of Roussyana palmnickenensis by Zeuner and Manning (1976: their pl. 3 as Electrapis palmnickenensis) is not actually a specimen of Roussyana. The specimen is in GPUH and upon examination it is actually S. micheneri. The specimen lacks the de®ning features of not only the species but also the genus. Moreover, the specimen has a distinct clypeal protrusion (a character of Succinapis) and sparse mesoscutal setae. A thin layer of Fig. 111. Forewing of holotype female of Kelneriapis eocenica (Kelner-Pillault). Scale bar pollen and mold on the specimen was appar- ϭ 0.5 mm. ently interpreted as copious pubescence by Zeuner and Manning. The description they presented for R. palmnickenensis, therefore, does not apply to this species. DESCRIPTION: Minute to moderate size (ca. Kelner-Pillault (1970a) designated the two 1.5±13 mm long), sparsely to moderately pu- specimens discussed above as syntypes but bescent bees. Mandible without outer man- did not select one to be the name-bearing dibular grooves. Labral width three to four type. I have, therefore, in the interest of no- times length. Clypeus variously produced, menclatural stability, selected a lectotype and typically gently convex and not protuberant paralectotype from her syntypes. Kelner-Pil- in pro®le. Compound eyes typically bare. Su- lault (1970a) enigmatically ®gured the hind praaÈlar carina absent; scutellum broadly wing without a jugal lobe, which is not only rounded posteriorly and variously produced present but deeply incised and visible in the (i.e., ranging from projecting over metano- specimens. tum and propodeum to not projecting at all: e.g., see Michener, 1990). Claws of female Tribe MELIPONINI Lepeletier de Saint Fargeau simple (e.g., ®g. 115); arolium strong and present; metatibial spurs absent; malus of Meliponites Lepeletier de Saint Fargeau, 1836: strigilis without anterior velum; metabasitar- 407. Type genus: Melipona Illiger, 1806. sus without auricle; metatibia with penicil- Trigonini Moure, 1946: 611. Type genus: Trigona Jurine, 1807. lum (e.g., ®g. 114). Distal venation of fore- Lestrimelittini Moure, 1946: 611. Type genus: wing weakened (e.g., ®gs. 111, 113); mar- Lestrimelitta Friese, 1903. ginal cell apex typically open (e.g., ®gs. 111, 113); pterostigma present, moderate to large DIAGNOSIS: Among living taxa the Meli- ponini are allied to the honey bees (tribe Ap- in size, much longer than prestigma, r-rs aris- ini); both tribes share the complete loss of ing near midpoint, margin within marginal metatibial spurs and outer mandibular cell convex; 1m-cu, when present, angled; grooves and possess a jugal lobe in the hind hind wing with distinct jugal lobe, lobe wing. The meliponines differ from Apini by broadly and deeply incised; hamuli reduced; the absence of an auricle, absence of an inner wing membrane without alar papillae. Sting tooth on the claw, the reduced forewing ve- reduced. nation, and the reduction of the sting, among COMMENTS: The tribe Meliponini contains other characters. Numerous ethological traits the familiar stingless bees. The group is to- similarly serve to differentiate the tribes (re- day worldwide in the tropics, with a partic- viewed by Michener, 1990: as subfamilies). ularly high diversity in the neotropics. Mich- Among the fossil taxa meliponines most ener (2000a) recognized 23 Recent genera closely resemble the tribe Melikertini but dif- and subgenera worldwide. Although no me- fer notably by the aforementioned characters liponines today occur in Europe, at least two as well as the complete loss of metatibial species were present in the middle Eocene spurs (melikertines retain a single metatibial fauna of this region. Both seem closely allied spur). to Recent sub-Saharan African genera. 134 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

ameter. F1 approximately equal in length to Key to Genera of Meliponini pedicel; F1 shorter than F2; F2 approximate- in Baltic Amber ly equal in length to F3; ¯agellomeres with 1. Apical bend in M (at point where vein would numerous, minute sensillar plates. Inner mar- meet 1m-cu) present (®g. 111); antennal gin of compound eyes straight, eyes appar- sockets at least one antennal socket diam- ently parallel (not converging below). Pre- eter above basal clypeal margin; posterior occipital area rounded. Anterior border of corner of corbicula weakly rounded; scu- mesoscutum broadly rounded; tegula oval; tellum projecting over metanotum and pro- scutellum strongly projecting over metano- podeum; basal area of propodeum shorter than scutellum and declivitous ...... tum and propodeum, without medioapical V- ...... Kelneriapis Sakagami shaped notch, apical margin rounded. Basal ± Apical bend in M (at point where vein would area of propodeum much shorter than scu- meet 1m-cu) absent (®g. 113); antennal tellum, strongly declivitous. Corbicula only sockets less than one antennal socket di- weakly concave along apical third of meta- ameter from basal clypeal margin (®g. tibia; posterior angle of corbicula angled but 112); posterior corner of corbicula distinct- not sharply (intermediate between Hypotri- ly pointed (®g. 114); scutellum not pro- gona and Liotrigona); inner surface of me- jecting over metanotum; basal area of pro- tatibia with narrow keirotrichiate ®eld, kei- podeum horiztonal and as long as scutellum rotrichiate ®eld weakly elevated, bordered by ...... Liotrigonopsis, n. gen. broad, weakly depressed zone (as in Hypo- trigona); inner surface of metabasitarsus Genus Kelneriapis Sakagami without basal sericeous area. Forewing with Tetragonula (Kelneriapis) Sakagami, 1978: 232. distal bend at point where nebulous 1m-cu Type species: Hypotrigona eocenica Kelner-Pil- meets M present (®g. 111); no indication of lault, 1969a, monobasic. Michener, 1990: 106 submarginal cells (not even by nebulous [as a genus]. veins); marginal cell apex open; hind wing Kelnermelia Moure In Moure and Camargo, dif®cult to see, without closed cells. 1978: 565. Type species: Hypotrigona eocenica COMMENTS: The authorship of the name Kelner-Pillault, 1969a, monobasic and original Kelnermelia was indicated as ``Moure and designation, isotypic with Kelneriapis Sakaga- mi, 1978. Camargo'' by Michener (1990, 1997); however, the name is attributed solely to Padre DIAGNOSIS: This genus differs from the Moure in the original publication. only other Baltic amber meliponine genus, Unlike the description by Kelner-Pillault Liotrigonopsis, by the separation of the an- (1970b), which suggests that the specimen tennal sockets from the basal margin of the was a male (i.e., that there was no corbicula, clypeus more than 1 OD, the rounded apical 13 antennomeres, absence of penicillum), the corner of the metatibia, the scutellum pro- specimen on which her description was jecting over the metanotum and propodeum, based (labeled in her own hand as the holo- and the strongly declivitous and shortened type and matching the photograph she pre- basal area of the propodeum. Among living sented) is in fact a female with a corbicula, genera Kelneriapis is most similar to, and 12 antennomeres, and a penicillum. perhaps sister to, Hypotrigona from Africa; both genera have the posterior apical corner Kelneriapis eocenica (Kelner-Pillault), of the metatibia rounded, although slightly new combination less so in Kelneriapis. Kelneriapis differs, Figure 111 however, by the scutellum that projects over Plate 7e the metanotum and propodeum, the absence of mandibular dentition, and the shortened Hypotrigona eocenica Kelner-Pillault, 1969a: 87. Trigona (Hypotrigona) eocenica (Kelner-Pillault); and declivitous propodeum. Kelner-Pillault, 1970b: 437. DESCRIPTION: Mandible without dentition. Tetragonula (Kelneriapis) eocenica (Kelner-Pil- Malar space shorter than basal mandibular lault); Sakagami, 1978: 232. width. Antennal sockets set above base of Kelnermelia eocenica (Kelner-Pillault); Moure clypeus by more than an antennal socket di- and Camargo, 1978: 565. 2001 ENGEL: BALTIC AMBER BEES 135

DIAGNOSIS: As for the genus (see above). to inner margin; scutellum as described for DESCRIPTION: Female. Total body length mesoscutum except setae slightly longer, se- 3.1 mm; forewing length 2.24 mm. Head tae noticeably more dense along posterior wider than long (length 1.21 mm, width 1.24 margin and slightly longer; metanotum and mm). Interocellar distance 0.22 mm; ocello- basal area of propodeum without pubes- cular distance 0.17 mm; median to lateral cence. Corbicula bordered by long, simple ocellus 0.07 mm. Labrum much broader than setae; apex with penicillum; outer surface of long, apical margin straight. Glossa relatively metabasitarsus without pubescence, laterally short; ¯abellum minute; setae of labial palp with short, stiff, simple setae, inner surface segments identical to that described for Lio- with stiff comb rows. Metasoma with sparse, trigona mahafalya Brooks and Michener minute, simple, subappressed setae. (Michener, 1990: his ®g. 61). Scape relative- MATERIAL: One specimen. Holotype. Fe- ly straight; ¯agellum with 10 ¯agellomeres male, worker caste, MB.I.1946 (ZMHB) la- (original description by Kelner-Pillault is in beled: ``15 [old Berendt collection number]'' error). Forewings with identical venation // ``Holotyp [sic], PalaÈontologisches Museum (original description by Kelner-Pillault is in Berlin, Trigona (Hypotrigona) eocenica Kel- error by mentioning they are different!); bas- ner-Pillault, 1970, Baltischer Bernstein'' // al vein basad cu-a crossvein. ``Holotype, Trigona eocenica Kelner-Pil- Mandible smooth and impunctate, without lault'' // ``Hypotrigona eocenica S.K.P., Ho- outer grooves. Labrum, clypeus, supraclypeal lotype, S. Kelner-Pillault det.[in Kelner-Pil- area, face, vertex, and gena smooth and im- lault's handwriting]''. punctate. Pronotum smooth and impunctate; COMMENTS: Although Kelner-Pillault's mesoscutum smooth with a few, faint, small 1970 paper (1970b) is commonly cited as the punctures separated by ®ve times a puncture original proposal of the species, the name width or more; tegula and scutellum smooth was apparently made available by Kelner-Pil- and impunctate; metanotum apparently ®nely lault a year earlier (1969a), where a one-sen- imbricate; pleura smooth and impunctate. tence diagnosis is presented to separate the Corbicula and outer surface of metabasitar- species from extant Hypotrigona; the name sus ®nely imbricate. Basal area of propo- is given as ``Hypotrigona eocenica n. sp.'', deum glabrous (lateral and posterior surfaces and two ®gures are provided to distinguish not visible). Metasoma ®nely and faintly im- the fossil from living meliponines. Although bricate. meeting abstracts are excluded from avail- Head and mesosoma (where preserved) ability (ICZN, 1999b: Art. 9.9), published dark brown to black, without maculations. proceedings [as is the case for Kelner-Pillault Legs dark brown. Wing membrane hyaline; (1969a)] are available. I therefore consider veins light brown. Metasoma apparently dark the name as having been made available in brown. 1969 rather than 1970, and that the original Pubescence generally white. Mandible combination was Hypotrigona eocenica rath- with widely scattered, minute, subappressed, er than Trigona (Hypotrigona) eocenica. simple setae. Labrum with minute, simple, Although Michener (1990) was the ®rst to subappressed setae evenly scattered over sur- use Kelneriapis at the generic level (Saka- face. Clypeus, supraclypeal area, and face to gami treated this group as a subgenus of Te- slightly above level of antennal sockets as tragonula), he did not make the associated described for labrum. Face above level of an- taxonomic combination for the type species tennal sockets with setae as on clypeus but and I have therefore considered my usage noticeably more sparse, erect, and intermixed above to be a new combination. with simple, erect, slightly longer setae; such erect setae also on vertex but disappearing Liotrigonopsis, new genus on gena where pubescence is as described for clypeus. Mesoscutum with widely scattered, TYPE SPECIES: Liotrigonopsis rozeni Engel, short, simple setae, setae becoming more new species. dense toward anterolateral corners; tegula DIAGNOSIS: In keys to the genera of Me- with scattered, minute, erect setae restricted liponini this group runs to the African and 136 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Malagasy genus Liotrigona Moure (1961). This fossil differs, however, in the following generic characteristics: antennae inserted low on face (separated from clypeus by less than 1 OD) and not far above lower tangent of compound eyes as well as vein M without apical bend among other, more trivial, features. Liotrigonopsis can be separated from Kelneriapis, also in Baltic amber, by the characters presented above in the Diagnosis for Kelneriapis. DESCRIPTION: Malar space shorter than basal mandibular width (®g. 112). Antennal sockets set near base of clypeus, separated by less than an antennal socket diameter (®g. 112). F1 approximately equal in length to F2; F2 approximately equal in length to F3; ¯a- gellomeres with numerous, minute sensillar plates. Preoccipital area rounded. Anterior Fig. 112. Right lateral view of head of holo- border of mesoscutum broadly rounded; te- type female of Liotrigonopsis rozeni, new species. gula oval; scutellum clearly not projecting Scale bar ϭ 0.5 mm. over metanotum, without medioapical V- shaped notch, apical margin rounded. Basal area of propodeum as long as scutellum, hor- abcissa of Rs after separation from M pre- izontal. Posterior angle of corbicula sharply sent, M terminating shortly thereafter with- angled (as in Liotrigona) (®g. 114); inner out apical bend. surface of metatibia with narrow keirotri- Integument of head, mesosoma, and legs chiate ®eld, keirotrichiate ®eld not elevated, smooth and impunctate. Terga and sterna bordered by broad, glabrous zone; inner sur- ®nely imbricate and impunctate. face of metabasitarsus without basal seri- Head and mesosoma dark brown except ceous area. Forewing without distal bend at scape light brown (remainder of antenna dark point where 1m-cu would meet M (®g. 113); brown). Legs and metasoma light brown or without indication of submarginal cells (®g. ferruginous. Wing membrane hyaline; veins, 113); marginal cell apex open; hind wing dif- when present, light brown. ®cult to see, apparently without closed cells. Pubesence golden, sparse, and simple. Se- ETYMOLOGY: The new genus-group name tae not apparent on head. Mesosoma with is a combination of Liotrigona and the suf®x sparse, simple, short, erect setae. Setae of -opsis (Greek, meaning ``appearing like''). legs simple and scattered; inner surface of The name is a reference to the similarity be- metatibia densely covered by keirotrichiae tween the fossil and Liotrigona, a genus of except narrow (ca. 0.75 OD) glabrous pos- African and Malagasy stingless bees. The terior border; rastellar bristles of moderate name is feminine. length, tapering at apices, not ¯attened. Terga with exceedingly sparse, short, suberect setae; setae of sterna sparse, restricted to apical Liotrigonopsis rozeni, new species thirds, and moderately long. Figures 112±115 MATERIAL: One specimen. Holotype. Fe- Plate 7f male, worker caste, B-JH 79 (AMNH) la- DIAGNOSIS: As for the genus (see above). beled: ``Baltic amber: Eocene, Kaliningrad, DESCRIPTION: Female. Total body length Yantarny'' // ``Holotype, Liotrigonopsis roz- 3.37 mm; forewing length 2.8 mm. Head eni Engel.'' The specimen is partially pre- length 0.87 mm (width indeterminate from served along the edge of the amber piece specimen). Basal vein distad cu-a by three with the left half of the head and left anterior times vein width; minute basal stub of ®rst portion of the mesosoma missing. Enough of 2001 ENGEL: BALTIC AMBER BEES 137

Figs. 113±115. Mesosomal structures of Liotrigonopsis rozeni, new species. 113. Forewing. 114. Outer surface of metatibia and metatarsus. 115. Metadistitarsus, claw, and arolium. Scale bars ϭ 0.5 mm (a: for ®g. 113) (b: for ®g. 114); 0.25 mm (b: for ®g. 115). the specimen is preserved to allow for not level of family. I have listed them here sim- only identi®cation but for meaningful com- ply as a record of the families and for the parison to living species. total number of individual bees recognized ETYMOLOGY: The speci®c epithet is a pat- in Baltic amber. ronymic honoring Dr. Jerome G. Rozen, Jr. APIDAE gen. et sp. indet.: One female, for his friendship and support of my studies MB.I.1938 (ZMHB) labeled: ``Museum fuÈr on bees. Naturkunde Berlin, PalaÈontologisches Mu- seum, Inv. Nr. MB.I.1938 (No. 53)'' // ``53'' APOIDEA INCERTAE SEDIS // ``Apidae indet., det. M. S. Engel''. One Genus and Species Indeterminate female, Nr. 2616 (CCGG) labeled: ``Nr. The following specimens are too poorly 2616'' // ``Apidae indet., det. M. S. Engel''. preserved to allow identi®cation below the MEGACHILIDAE gen. et sp. indet.: One 138 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 female, Nr. 8 (CSUL) labeled: ``Megachili- Bombus carbonarius Menge dae indet., det. M. S. Engel''. Bombus carbonarius Menge, 1856: 27.

Missing Taxa of Uncertain Identity COMMENTS: The size and general habitus of B. carbonarius from Menge's description The following named taxa are known only suggest a species of Electrapis; however, this on the basis of their fragmentary original de- is entirely conjectural. There is not enough scriptions. No specimens are known to be ex- information to con®dently assign this species tant for any of these species. Interestingly, to any of the several ``Bombus-like'' genera. most were considered to be bumble bees, or bumble bee ancestors, by their authors. It is Bombus muscorum Roussy likely that none were actually bumble bees or even closely related to the Bombini, but Bombus muscorum Roussy, 1937: 58. Nomen this may never be known with certainty. praeoccupatum (nec Linnaeus, 1758). Three of these names (Bombus carbonarius, B. pusillus, Bombusoides mengei) were er- COMMENTS: The name for this species roneously listed as nomina nuda by Keilbach must eventually be changed as it is a junior (1982). secondary homonym of Linnaeus's Apis muscorum, which has been considered a valid species of Bombus for well over a century. Andrena wrisleyi Salt The type was deposited in Roussy's private Andrena wrisleyi Salt, 1931: 141. collection and is now presumably lost. As COMMENTS: The description and illustra- mentioned above, this species is likely not a tions of this specimen are adequate to deter- true bombine at all; Roussy (1937) himself mine that the species was not an Andrena or considered this specimen to be representative even an andrenid. It is possible that the spe- of a solitary bee, while all bombines are cies was a melittid of some sort that has not known to be social, a fact universally known subsequently been discovered among newer in Roussy's time. material. Although the melittid hypothesis is perhaps the best possibility, the original de- Bombus pusillus Menge scription and particularly Salt's ®gure of the Bombus pusillus Menge, 1856: 27. wing venation are enigmatically suggestive of an electrapine. Although the ®gure of the COMMENTS: A supposed bumble bee that hind tibia does not show a corbicula, the de- was described as ``. . . ist kaum 3 mill. lang scription provided of the hind leg by Salt und 1 mill. breit. Behaarung gelblich weisz, does not match his ®gure and is somewhat auf dem brustruÈcken zottig.'' (Transl. ``. . . suggestive: ``. . . tibiae triangular, much wid- is scarcely three millimeters long and 1 mil- ened apically, ...'' (Salt, 1931: 142). The limeter wide. Pilosity yellowish-white, of the wing venation is quite similar to species of thoracic dorsum shaggy''; translation of the both Electrapis and Protobombus (if an elec- author). It is hard to imagine what this spe- trapine, Andrena wrisleyi would fall close to, cies might have been (perhaps a spheciform or in, Electrapis owing to the elongate me- or other aculeate?). If indeed a bee, then it tabasitarsus). It seems hard to imagine but it was certainly one of the smallest in Baltic is possible that Salt's specimen was actually amber. an unknown corbiculate apine in the Electra- pini! The holotype was deposited in the ill- Genus Bombusoides Motschulsky fated University of KoÈnigsberg and was not subsequently located in any other institution. Bombusoides Motschulsky, 1856: 28. Type species: Bombusoides mengei Motschulsky, 1856, None of the bees before me can be readily monobasic. associated with Salt's ``Andrena'' and so I have not designated a neotype. The name COMMENTS: Refer to Comments provided must be relegated to incertae sedis. for the type species (below). 2001 ENGEL: BALTIC AMBER BEES 139

Bombusoides mengei Motschulsky TABLE 10 Characters Used in Cladistic Analysis of Bombusoides mengei Motschulsky, 1856: 28. Lithurginae COMMENTS: Motschulsky's treatment of this specimen is exceedingly short and provides no clue as to what the bee may have actually been. The entire reference to this bee consists of the clause ``. . . entre autres une treÁs belle Andraena [sic] et un Bombus nain d'a peine 1 ½ ligne de longueur, que je me permets de deÂdier aÁ M. Menge, en le nom- mant Bombusoides Mengei.'' (Transl. ``. . . among others a very beautiful Andrena and a dwarf Bombus scarcely 1.5 lines in length, which I allow myself to dedicate to Monsieur Menge, with the name Bombusoides mengei''; translation courtesy M. G. Rightmyer). There is no way to associate this name with any of the smaller bees presently known from Baltic amber and thus the name must be relegated to incertae sedis. nus-group taxon inclusive of both subgenera of Lithurgus and Lithurgomma, a junior syn- CLADISTIC ANALYSES onym of Trichothurgus (sensu Michener, 1983, 2000a). Like Michener (1983), I could Cladistic analyses were undertaken in or- ®nd no qualitative character to differentiate der to both acquire an understanding of the Lithurgomma from Trichothurgus and there- phylogenetic position of particular fossil taxa fore, when coding the matrix, chose to retain and to explore the potential effects on hy- these taxa as synonymous. The subgenera of potheses of relationships previously based Lithurgus, however, could be qualitatively solely on Recent species. Data matrices were diagnosed, as could the enigmatic Australian constructed in WINCLADA (Nixon, 1999) species Lithurgus rubricatus Smith (1853), and submitted from there for analysis by and each was coded individually in the ma- NONA (Goloboff, 1993). An initial search trix. Ten characters of adult external mor- was made on each matrix using the wh* phology were identi®ed and coded for the re- command to identify a single tree or set of cent lithurgines, the fossil genus Protolithur- trees upon which more exhaustive branch gus, and the basal megachilid subfamily Fi- swapping was undertaken using the max* deliinae (used as an outgroup). The resulting command. Topologies were visualized and data matrix is presented in table 11, while printed using WINCLADA (Nixon, op. cit.). character de®nitions are provided in table 10. Analysis of the data matrix resulted in a sin- LITHURGINAE gle topology of length 11, CI 0.88, and RI No previous attempt has been made to cla- 0.90 (®g. 116). distically reconstruct lithurgine relationships. The relationships proposed by Michener Three recent genera have generally been rec- (1983) are generally in accord with those ognized: Trichothurgus, Microthurge, and presented here (®g. 116). Protolithurgus is Lithurgus; the last has two subgenera, Li- placed as sister to all other lithurgines owing thurgopsis and Lithurgus proper (Michener, to the plesiomorphic retention of a ¯attened 1983). Michener (1983) discussed characters metabasitarsus (typical of other bees), two supporting the monophyly of the subfamily mandibular teeth, and absence of spicules on and presented an argument for the relation- the tibiae. Another feature apparently uniting ships among these three genera as Tricho- the living genera is the elongation of the pro- thurgus (Microthurge ϩ Lithurgus). Herein I boscis; however, this quantitative character have examined representatives of each ge- showed little discrete differentiation from 140 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

TABLE 11 The genus Trichothurgus, as in Michener's Data Matrix for Analysis of Generic system, is sister to all other extant lithurgine Relationships of Lithurginae genera owing to the lowest mandibular tooth (Character descriptions presented in table 10) being longer than those above it and the non- projecting pygidial plate in females. Unex- pectedly, the genus Microthurge, although itself likely monophyletic, was sister to Li- thurgus exclusive of Lithurgopsis and L. rubricatus. The monophyly of Lithurgus should be carefully scrutinized as this preliminary analysis could not support the group as it has been traditionally de®ned. The subgenus Li- thurgopsis should perhaps be accorded generic rank and L. rubricatus transferred to its own genus. It must be noted that the phylog- some ®deliines and alternative states could eny presented here is preliminary. A more not be consistently and unambiguously as- thorough analysis of lithurgine relationships signed. For this reason the elongation of the is needed before major classi®catory changes proboscis was not included in the data anal- are made to the living genera. I have placed ysis but the general congruence of this fea- all extant genera in a nominate tribe (with ture with the resulting topology is interesting Trichothurgini Moure as a junior synonym), and noteworthy. Although Protolithurgus while the fossil is suf®ciently distinct to war- seems to possess an enigmatic combination rant the recognition of a monogeneric tribe of characters unique among megachilids, the sister to Lithurgini (see Protolithurgini, genus does share with other Lithurginae the above). distinctive ¯attened, ®rst metasomal tergum with a rounded apical margin, a feature XYLOCOPINAE found only in lithurgines and which unam- Sakagami and Michener (1987) investigat- biguously unites the fossil with this clade. ed tribal relationships with the Xylocopinae,

Fig. 116. Phylogeny of Lithurginae based on cladistic anlaysis of data presented in table 11 (Length 11, CI 0.88, RI 0.90). Black dots are unreversed changes; white dots homoplastic character transitions. The character number is indicated above the branch and the state change is indicated below. Fideliinae is the outgroup. 2001 ENGEL: BALTIC AMBER BEES 141

TABLE 12 Characters Used in Cladistic Analysis of Xylocopinae

although they assumed this group to be sister locopini and Manueliini from the earlier to the corbiculate Apinae (Apidae in their study were in fact reversed. Thus, the topol- system) and used this group, particularly the ogy of xylocopine relationships was Xylo- basal tribe Euglossini (see below), for a copini (Manueliini (Ceratinini ϩ Allodapi- priori character polarizations. They conclud- ni)). ed that the monogeneric tribe Manueliini was In order to determine the phylogenetic sister to all other xylocopines and that Xy- placement of the enigmatic Baltic amber xylocopa (Xylocopini) was intermediate be- locopines (i.e., Boreallodape) a character tween Manuelia and a Ceratinini ϩ Alloda- matrix was constructed to explore relation- pini clade. As part of a more exhaustive ships among the tribes of the subfamily. Fif- study on long-tongued bee tribal relation- teen characters were identi®ed and coded for ships, Roig-Alsina and Michener (1993) the sole genus of Xylocopini (Xylocopa sen- demonstrated that the xylocopines were more su Minckley, 1998), the sole genus of Man- basal in apid phylogeny and not closely al- ueliini (Manuelia), one of the two genera of lied to the corbiculates. Furthermore, they Ceratinini (Ceratina), and two genera of Al- concluded that the relative positions of Xy- lodapini (Macrogalea and Allodape). The two genera of allodapines were selected to TABLE 13 represent phylogenetic diversity within the Data Matrix for Analysis of Tribal tribe based on the cladistic studies of Mich- Relationships of Xylocopinae ener (1977) and Reyes (1998). The genus Ex- (Character descriptions presented in table 12; omalopsis was used as an outgroup. Char- the one multistate is nonadditive) acters identi®ed for analysis are presented in table 12, while the complete matrix is presented in table 13. Analysis of the data produces a single topology of length 16, CI 1.00, and RI 1.00. The topology is depicted in ®gure 117. The results of this analysis are in complete accord with the analysis of Roig-Alsina and Michener (1993) in that Xylocopini is basal within the subfamily owing to the plesiomorphic retention of alar papillae and an elon- 142 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 117. Phylogeny of Xylocopinae based on cladistic analysis of data presented in table 13 (Length 16, CI 1.00, RI 1.00). Black dots are unreversed changes; white dots homoplastic character transitions. The character number is indicated above the branch and the state change is indicated below. Exomalopsis is the outgroup. gate ®rst ¯agellomere. The Ceratinini, Allo- haps of a sub-Saharan African origin and that dapini, and Boreallodape are grouped togeth- Exoneuridia represents a subsequent dispers- er in a well-supported clade (®g. 117). This al into Asia Minor. Most likely, the proto- group is most notable for the abruptly nar- allodapines (perhaps together with proto-bo- rowed mandibular structure (e.g., ®g. 54). reallodapines) were of an original Gondwan- The analysis demonstrates that Boreallodape an origin (as is likely the same for several is most closely related to the Allodapini, both bee tribes and subfamilies) and the group as groups sharing the presence of two submar- we recognize it today diversi®ed in sub-Sa- ginal cells and the absence of the metabasi- haran Africa, subsequently radiating further tibial plate. As discussed above (under the as they dispersed in the Old World. Under description of the tribe Boreallodapini) dif- either scenario, Boreallodape serves as an- ferences between the Allodapini and Boreal- other example of Baltic amber fossils related lodape are signi®cant and inclusion of the to groups now found in Asia or sub-Saharan latter as the basalmost member of the former Africa (see below under Discussion). would mask the enigmatic features of the fossil among xylocopines. Boreallodape is as CORBICULATE APINAE distinctive as any of the other tribes of the subfamily and recognition of a separate tribe Relationships among the corbiculate bees for this group is well supported. It is biogeo- have been controversial as have their impli- graphically interesting to note that Boreal- cations for understanding the evolution of lodape is sister to the Allodapini, a group eusocial behavior in this group of bees. As today primarily distributed in sub-Saharan was brie¯y discussed above, in the modern Africa, Asia, and Australia. Among the al- fauna there are four well-de®ned tribes: Ap- lodapines only the genus Exoneuridia occurs ini (honey bees), Bombini (bumble bees), in the West Palearctic and extends as far Euglossini (orchid bees), and Meliponini north as the Mediterranean region in the (stingless bees). Of these four, the Bombini, southeastern half of Turkey (Terzo, 1999). Apini, and Meliponini are all eusocial, al- However, a historical biogeographic analysis though advanced eusociality (i.e., those so- of the allodapines derived from the recent cieties with morphologically differentiated cladogram of Reyes (1998) suggests that the queen and worker castes) is found only in extant groups of the tribe as a whole are per- Apini and Meliponini (not just among cor- 2001 ENGEL: BALTIC AMBER BEES 143 biculates, but among all of the Apoidea). Of corbiculate relationships. Herein I have both the 15 possible rooted topologies for four expanded the available morphological data as taxa, eight have been proposed at one time well as the taxon representation (tables 14, or another for the living corbiculates based 15). The character-state matrix is presented on either a priori interpretations of the same in table 15. Analysis of these data produces 10±20 morphological characters, single char- two most parsimonious topologies (length acter analyses, or studies of limited DNA se- 65, CI 0.81, RI 0.93), the strict consensus of quences. Outgroup-based cladistic analysis which is depicted in ®gure 118. Of the two of morphological evidence produced a sin- trees, only one of the resultant topologies is gle, fully resolved topology (Prentice, 1991; strictly supported (Nixon and Carpenter, Roig-Alsina and Michener, 1993; ChavarrõÂa 1996) and is identical to the consensus (®g. and Carpenter, 1994; Schultz et al., 1999). 118). The analysis produces a nested set of This topology supports the ``single origins'' relationships, with numerous groups break- hypothesis whereby both general eusocial being up some of the long branches between havior and advanced eusocial behavior arose the living tribes. More importantly, these re- once in a hierarchical fashion. Thus, euso- sults produce a hierarchy of intermediary lin- ciality arose in the common ancestor of the eages separating the advanced eusocial tribes Bombini, Meliponini, and Apini, while ad- (i.e., Apini and Meliponini) from the bumble vanced eusociality arose in the common an- bees and orchid bees. Topologies attempting cestor of Meliponini and Apini. Molecular to unite Bombini with Meliponini cannot re- analyses have produced alternative clado- motely account for the character combina- grams that are not consistent with this sce- tions exhibited by the fossil taxa. That this nario, nor are they always consistent with hierarchy is congruent with behavioral char- themselves (e.g., Cameron, 1991, 1993). acters and other biological traits (e.g., Noll, These analyses imply either dual origins of 1998) is noteworthy. Thus, quite contrary to advanced eusocial behavior or ambiguous re- the view asserted by Patterson (1981), pale- constructions by uniting the bumble bees and ontological data has had a signi®cant impact stingless bees. A simultaneous analysis of on our understanding of corbiculate bee re- these DNA sequences with morphological lationships. Interestingly, the corbiculate data produces topologies that support the sin- bees are a nice example of the type of group gle origin for advanced eusocial behavior by wherein fossils are hypothesized to be most reuniting the Meliponini and Apini (Chavar- important for phylogeny reconstruction. rõÂa and Carpenter, 1994; Schultz et al., 1999). Gauthier et al. (1989: 193) hypothesized, However, while these combined studies typ- ``. . . fossils should be most important in ically also support a single origin for general phylogenetic inference when the group of in- eusociality, the support is not as strong. terest is old and only a few, highly modi®ed, Thus, a clear resolution has yet to be terminal taxa are extant''. The extant tribes achieved concerning relationships among of corbiculate bees are highly derived with these tribes and the addition of more char- numerous synapomorphies supporting each, acters and more taxa to analyses is needed. and the tribes are undoubtedly ancientÐex- Since most characters used in morphological tending into the Late Cretaceous, as shown studies of the tribes are ®xed across taxa by the presence of a true meliponine in am- within each tribe, added taxa of living rep- ber of probable Maastrichtian age (Michener resentatives provide little information for res- and Grimaldi, 1998a; Engel, 2000b; see also olution of relationships outside of more ac- below under Origin of Bees). Under such curately reconstructing the basal node of conditions intermediary fossil lineages are each respective tribe. Most of the Baltic am- critical for evaluating relationships among ber corbiculates as demonstrated above, the surviving lineages. however, do not fall into the living tribes and The reconstruction of social behavior on possess combinations of characters unknown the cladogram may, at ®rst glance, appear to in any of the living lineages. Thus, the ad- be problematic owing to the absence of direct dition of these groups to analyses may have observations for the social state of the fossil important implications for understanding taxa. It is possible, however, to infer behav- 144 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

TABLE 14 Characters Used in Cladistic Analysis of Corbiculate Apinae (Characters 35 and 48 additive; all others nonadditive) 2001 ENGEL: BALTIC AMBER BEES 145

TABLE 15 Data Matrix for Analysis of Tribal Relationships Within the Corbiculate Apinae (Character descriptions presented in table 14)

ioral character information from fossils either duced metasomal structure (and to a lesser through 1. particular morphologies that are degree a barbed sting) typical of workers; in- tightly correlated or unique to a given etho- dicating that they were members of advanced logical trait (e.g., Michener and Grimaldi, eusocial societies (®g. 119). Thus, although 1988b; Poinar, 1991; Engel, 1998c, 2000b; the fossils were coded and analyzed as un- Simmons and Geisler, 1998); 2. ``concrete known for their social state, all except Elec- behaviors'' (e.g., nest architecture, foot- trobombus could essentially have been coded prints), whereby the products of a behavioral as ``advanced eusocial''. The fact that those repertoire are preserved as trace fossils either taxa with worker-caste morphologies cladis- in association with the remains of the organ- tically group with the Apini and Meliponini ism or in isolation (e.g., Carpenter, 1992; (®g. 119) reinforces the reconstruction of a Genise and Hazeldine, 1998; Lockley and single origin for advanced eusocial behavior Matsukawa, 1999); 3. preservation of the in- in the bees. Moreover, the position of Elec- dividual while in the act of performing some trobombus within a clade of already eusocial portion of a particular behavioral repertoire (either primitive or advanced eusocial) line- (e.g., Norell et al., 1995; Clark et al., 1999); ages implies, via phylogenetic inference, eu- or, 4. phylogenetic inference (e.g., Michener social behavior to some degree in this taxon and Grimaldi, 1988b; Engel, 1998c, 2000b). (®g. 119). In summary, taking all of this in- As mentioned above, advanced eusocial so- formation into account produces a single cieties are recognized by morphologically possible reconstruction of eusocial evolution differentiated queen and worker castes, and within the corbiculate bees. The available ev- this attribute is known only for these socie- idence supports only the ``single origins'' ties. Among the fossils, all except the single scenario wherein general eusociality arose individual of Electrobombus exhibit the re- once in the common ancestor of the Bom- 146 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 are the outgroups. Xylocopa and Anthophora, Centris, Fig. 118. Phylogeny of corbiculate Apinae based on cladistic analysis of data presented in table 15 (Length 65, CI 0.81, RI 0.93). Black dots are unreversed changes; whiteindicated dots below. homoplastic character transitions. The character number is indicated above the branch and the state change is 2001 ENGEL: BALTIC AMBER BEES 147

Fig. 119. Distribution of social ethotypes among the corbiculate apines as well as fossils exhibiting worker morphologies. The euglossine genera (Euglossa, Eufriesea, and Eulaema) are generally communal or solitary, while the outgroups (not depicted here) are solitary. Extinct genera are italicized. bini, Electrobombini, Electrapini, Melikerti- al., 1999; Mardulyn and Cameron, 1999). In- ni, Apini, and Meliponini with a subsequent, terestingly, a simultaneous analysis of mor- single evolutionary elaboration of this trait to phological characters and of the sequence advanced eusociality in the common ancestor data published by Koulianos et al. (1999) of at least the Electrapini, Melikertini, Apini, produces a ``single origins'' topology. These and Meliponini (®g. 119) (Engel, in press-b). sequence data are particularly problematic in Recently, new studies of DNA sequences that they employ mitochondrial DNA regions have attempted to provide further support for (like the earlier studies of Cameron, 1991, a Meliponini ϩ Bombini clade (Koulianos et 1993) commonly used in species-level anal- 148 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 yses owing to high levels of interspeci®c var- metatibial spurs. Surprisingly, however, the iation. For example, analysis of the earlier Apini and Meliponini are separated by a mitochondrial DNA data for relationships group of extinct taxa that are sister to the among species within a given genus were Meliponini (i.e., the Melikertini) and that more internally congruent than when exam- have a single metatibial spur. Thus, the im- ining older relationships (Engel and Schultz, plication is that the loss of spurs in the honey 1997; Schultz et al., 1999). That the corbi- bees and stingless bees is not a feature shared culate tribes are undoubtedly ancient only through common ancestry (i.e., not a syna- serves to reinforce the need for careful se- pomorphy for the two tribes); nonetheless, lection of gene regions when undertaking an support for their close relationship was not analysis, particularly in a group that extends degraded by the loss of this supposed syna- back into the Mesozoic [the divergence pomorphy. The apines and meliponines in- among the tribes being at least 75 Ma owing dependently lost tibial spurs from a single- to the presence of a true meliponine in Late spurred ancestor. From the viewpoint of ``re- Cretaceous amber (Engel, 2000b)]. The data ciprocal illumination'' this interpretation of of Mardulyn and Cameron (1999) are an im- independent loss makes sense. A reeÈxami- provement over those of previous studies by nation of the metatibia-metabasitarsus junc- attempting to select relatively conserved tion in living stingless bees and honey bees gene regions, but Ascher and Danforth (in reveals two, somewhat different morpholo- rev.) have demonstrated that there are nu- gies, suggesting at an observational level the merous other critical problems with these se- possibility that the homology of absence is quence data and analyses. Moreover, all of incorrect in this case. The inner apex of the these studies have suffered from poor taxon metatibia and the junction with the metabas- sampling and choice of outgroups. Thus, the itarsus in honey bees is essentially unmodi- available sequence data are not at all reliable ®ed; the only signi®cant difference by com- and a well approached (e.g., choice of in- parison to ``spurred'' corbiculate bees is the group taxa, choice of outgroup taxa, number simple absence of the metatibial spurs. On of taxa examined, number of informative the other hand, in stingless bees the entire characters, choice of gene region) molecular junction between these two leg segments is analysis remains to be undertaken for the grossly transmogri®ed, perhaps partly corbiculate Apinae. Perhaps one of the more interesting mor- through the loss of the auricle. In most sting- phological implications of the fossil corbi- less bee taxa the inner apical region of the culate taxa and the cladistic analysis pre- metatibia where the metatibial spurs would sented here concerns the evolution of the me- articulate is modi®ed with a slight impres- tatibial spurs. The apomorphic absence of sion leading down to the articulation with the metatibial spurs in the Apini and Meliponini metabasitarsus, which itself is highly modi- has often been used as one of several traits ®ed by the complete absence of an auricle. uniting these two tribes in analyses of the Likewise, the inner apical margin of the me- living taxa; the presence of two metatibial tatibia extending posteriorly from this im- spurs is plesiomorphically found in the out- pression where the metatibial spurs would groups, euglossines, and bombines. Those otherwise articulate is weakened; in some in- Baltic amber corbiculate genera that do not stances this is further manifested through a cladistically fall into any of the extant tribes weakening of the rastellum. These two dif- have a single, often reduced, metatibial spur ferent morphologies of ``absence'' suggest (dif®cult to see in many specimens). The from examination of living taxa alone that taxa exhibiting this ``one spur'' character- the conditions seen in honey bees and sting- state form a paraphyletic assemblage derived less bees are perhaps not homologous and, in from a two-spurred ancestor and subsequent- fact, represent two separate character states. ly giving rise to the Apini and Meliponini, A paleontological perspective has thus pro- neither of which have metatibial spurs. This vided illumination toward understanding not pattern itself is intuitively pleasing in that it only cladistic relationships among the living implies a gradual reduction in the number of taxa but also for interpreting their morphol- 2001 ENGEL: BALTIC AMBER BEES 149

Fig. 120. Hypothesis of relationship for the corbiculate bees as envisioned by Cockerell (reproduced from Cockerell, 1908b). He did not include tribe Euglossini and the ages he used for particular deposits are now understood to be as follows: Calyptapis [considered as a junior subjective synonym of Bombus by Zeuner and Manning (1976)] is from early Oligocene deposits of Florissant, while the genera So- phrobombus, Chalcobombus, Protobombus, and Electrapis, all in Baltic amber, are middle Eocene in age. Most species of Synapis (a subgenus of Apis) are from Oligocene strata but at least two species are from early Miocene deposits (Engel, 1999c, unpubl. data). Meliponorytes (described by Tosi, 1896) is either a true fossil in Miocene amber from Sicily or perhaps misidenti®ed in African copal and congeneric with living meliponines (see appendix 1). ogy via a character-state known only from sented a phylogeny for this group of bees the fossil record. (excluding the Euglossini) derived from a The analysis presented here is the ®rst cla- few characters and a great deal of intuition. distic analysis combining fossil corbiculate His interpretation (®g. 120) is not too differ- genera with living genera. It is, however, not ent from the one presented here; i.e., Cock- the ®rst phylogenetic attempt to unite the fos- erell united the Apini and Meliponini as sis- sil record of corbiculate apines with their ex- ter taxa. My interpretation of the fossils dif- tinct counterparts. Cockerell (1908b) prefers from that of Cockerell in that he also 150 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 used plesiomorphic traits to unite genera; for giosperms have generated a great deal of instance, he brought together those Bombus- controversy (and rightly so) but are, unfor- like groups (e.g., Electrapis, Protobombus) tunately, entirely unfounded. The accounts on the primitive absence of elongate setae on by Hong (1984) and Hong and Miao (1992) the compound eyes (®g. 120). A cladistic in- of a bee from the earliest Cretaceous of Chi- terpretation of these same taxa based on out- na can be immediately dismissed since this group comparison (both with the Euglossini fossil is easily identi®able as a sphecid wasp as well as non-corbiculate apine tribes) dem- (Darling and Sharkey, 1990; Michener, 1997; onstrates that although fossils such as Elec- Engel, 1998c, 1999c, 2000b) and in fact has trapis and Protobombus are plesiomorphi- been recently synonymized with the genus cally similar to bumble bees, these genera Archisphex (Rasnitsyn et al., 1998). Similar- share apomorphic traits that unite them more ly, the fossil identi®ed as a ``native bee'' by closely to honey bees and stingless bees (®g. Carroll (1962) from the Jurassic of Australia 120). Thus, the Bombus-like genera form a is not actually a bee. Carroll's specimen is a paraphyletic grade leading to the Apini, Me- very poorly preserved compression fossil liponini, and Melikertini (species of the latter lacking wings and a complete head (see her were not known to Cockerell, as he had not ®g. 1) and cannot therefore be assigned to seen the only described melikertine in his any insect group with great certainty. It must era; i.e., M. proavus). Cockerell also consid- be noted that no single character is preserved ered some of the fossils to be directly ances- that could place this fossil among the Apo- tral to modern lineages (e.g., the single spe- idea (nor even among the Aculeata!). cies of Synapis was the ancestor of living The reports by Hasiotis and Demko Apis species). While many of these taxa are (1996), Hasiotis (1997), Hasiotis et al. (1995, indeed plesiomorphic in most respects by 1998), and Kay et al. (1999) are not based comparison to living relatives, none can be on body fossils but instead on trace fossils interpreted as ancestors of extant lineages. from the Jurassic and Triassic of North Paraphyletic stem groups that are probably America. These accounts are fraught with er- ancestral to large extant families are known rors, with statements like, ``. . . Jurassic in the amber fossil record, a good example bees, like their modern homologs, may have being Prioriphora (Phoridae), known only in also used carrion for food and nutrients...'' Cretaceous amber (Grimaldi and Cumming, (Hasiotis and Demko, 1996: 366) and ``Tri- 1999). assic hymenopterans may also have scav- enged carrion. . . as do some modern species DISCUSSION of halictid, anthophorid, trigoniid [sic], and meliponine bees''7 (Hasiotis et al., 1998: ORIGIN OF BEES 116) Per common knowledge, bees are ex- The bees are a derived, monophyletic ceptional for their use of pollen; they collect group of the spheciform wasps (MuÈller, and provision their young with a mixture of 1872; Michener, 1944, 2000a; Brothers, pollen, nectar, and/or plant oils. Even clep- 1975, 1999; Lomholdt, 1982; Alexander, toparasitic bees feed on pollen, although the 1992; Brothers and Carpenter, 1993; Alex- mother does not collect the pollen herself. Of ander and Michener, 1995; Melo, 1999), per- the nearly 20,000 described species of living haps most closely related to the family Cra- bees, only three species of the highly derived bronidae (Alexander, 1992; Melo, 1999). Al- though alternative arguments have been pre- 7 A small taxonomic note: Enigmatically, Hasiotis et sented that suggest bees to be related to al. (1998: 116) have removed the necrophagous Trigona species from the tribe Meliponini and accorded this me- mutillids and formicids (e.g., BoÈrner, 1919; liponine genus familial rank as ``trigoniids''. Trigona is Lanham, 1979, 1980), these hypotheses were a genus of Meliponini; there is no such thing as a ``tri- based primarily on two characters taken in goniid''. An additional taxonomic problem arises in that isolation and have not been supported by any Hasiotis and Demko (1996: 366) refer to their nest as the product of ``. . . sweat bees in the Anthophoridae and rigorous analysis of aculeate relationships. Halictidae''. Sweat bees are species of the subfamily Reports of bees from pre-Cretaceous de- Halictinae; other halictids (i.e., rophitines, nomiines) and posits and arising prior to the origin of an- anthophorines are not sweat bees. 2001 ENGEL: BALTIC AMBER BEES 151 tribe Meliponini are obligate necrophages ies (see also critique by Grimaldi, 1999, who (Camargo and Roubik, 1991). Despite the arrived at the same conclusion). Several claim by Hasiotis et al. (1998), no halictid or modern beetle groups make galleries that are anthophorine provisions its nests with carri- similar to the traces they have recovered. The on. The three Trigona necrophages certainly chemical characteristics presented by Kay et do not represent the groundplan feeding be- al. (1999) to be diagnostic for primitive bees havior for bees, as they are from a derived are in fact not diagnostic for bees at all. Phe- genus, of a derived tribe, of the most derived netic comparisons in chemical composition subfamily, of the most derived family of are meaningless for a positive identi®cation; bees. Even if one wanted to argue that the what is needed would be an apomorphic fossil nests represented an extinct species of chemical trait unique (i.e., ®xed and diag- this derived clade, the position would still be nostic) to bees. No such chemical or blend unfounded, as all three construct resinous has been identi®ed to date. nests and combs in tree or ground hollows Some bee species have been observed to and not branching burrows/galleries in the collect pollen from gymnospermsÐTrigona soil or in wood (Roubik, 1983; Camargo and carbonaria Smith on Cycas media Brown Roubik, 1991). The large number of cells in (Cycadaceae) (Ornduff, 1991) and Colletes the fossil nest described by Hasiotis and sp. on Juniperus virginiana Linnaeus (Cu- Demko (1996) was taken as evidence for eu- pressaceae) (Burnham, 1978)Ðand this social behavior. As has been repeatedly dem- might be seen to lend credence to a pre-an- onstrated for ground-nesting bees (e.g., Sak- giosperm origin for the bees. Such forgaing agami and Michener, 1962; Eickwort and behavior led both Burnham (1978) and Orn- Sakagami, 1979; Engel, 1998b), there is no duff (1991) to speculate that bees might be correlation between nest architecture and lev- older than ¯owering plants; however, to truly el of sociality. Solitary and communal spe- support such a conclusion one must demon- cies can make nests just as large and elabo- strate that the groundplan foraging behavior rate as semisocial and eusocial species. Has- for the bees was on gymnosperm pollen with iotis and Demko's fossil nest shows no single a subsequent ``host-shift'' to angiosperms. character indicative of bee activity. The pres- The foraging activity of the polylectic T. car- ence of ¯ask-shaped cells, the slightly con- bonaria does not re¯ect any groundplan for- stricted opening, and shafts/corridors are aging behavior for the bees owing to its apo- generalized features common to many morphic position in the Meliponini (®g. 123). ground-nesting Hymenoptera, as well as The behavior of the unidenti®ed Colletes some insects in other orders, so such char- species is more tantalizing owing to the basal acters are not diagnostic for bees as errone- position of this subfamily (albeit not neces- ously suggested by Hasiotis and Demko sarily this genus). However, this foraging be- (1996). The presence of a spiral cell closure havior is not distributed across a series of is one of the few features suggestive of bee basal species in Colletes, the Colletinae, or activity (although it also occurs in some oth- even the Colletidae (or other bee families, for er insects) and such a structure was not found that matter, as would be required for a cla- with their trace fossils. Otherwise, bee nests distic reconstruction of gymnosperm forag- in the ground are similar in general plan to ing in the bee groundplan). Colletes, in fact, many groups of Hymenoptera. Researchers shares credible larval synapomorphies with should be far more hesitant to attribute such the Hylaeinae, Xeromelissinae, and Eury- trace fossils to bees. These same dif®culties glossinae while the remainder of the Colle- apply equally to the Triassic trace fossil dis- tinae as it is currently conceived (i.e., the covered in a petri®ed tree in Arizona and Paracolletini) is more basal (McGinley, popularized by Hasiotis (1997; see also Wil- 1981). Thus, such an observation in a single ford, 1995), Hasiotis et al. (1995, 1998), and species of Colletes does not re¯ect a ground- Kay et al. (1999). None of these nests are the plan trait for the bees. Instead, the foraging products of bees; not only do they lack any activities of a variety of genera across the characters suggestive of bees, they actually Paracolletini (as well as numerous other col- show evidence of having been beetle galler- letid groups) and basal genera of other basic 152 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 short-tongued bee families would need to be selves either originated in the earliest Creta- observed before any such conclusion could ceous (Crane et al., 1995) or the uppermost be drawn. Until an identi®able body fossil of Jurassic (Sun et al., 1998). Thus, the avail- a bee is discovered from pre-Cretaceous sed- able evidence suggests quite the opposite iments (or in association with nest remains), scenario from those of the aforementioned there exists no evidence that bees arose prior authors. Bees arose sometime after the origin to the origin and early diversi®cation of the of ¯owering plantsÐa long-standing conclu- angiosperms. sion arrived at by numerous authors (e.g., A particular problem with claims for a Ju- Michener, 1979; Engel, 1996, 2000b; Gri- rassic or Triassic origin is that they hypoth- maldi, 1999) and the only one with available esize, in the absence of any bee fossil, that evidence. bees arose prior to Aculeata (in the case of Interestingly, the radiation of bees coin- the Jurassic) and before the Apocrita (in the cides nicely with the period in which angio- case of the Triassic)! The entire order Hy- sperm diversity increased dramatically. The menoptera does not appear in the fossil re- oldest fossil bee presently recorded is Cre- cord until the Triassic and then only on the totrigona in Late Cretaceous (Maastrichtian) basis of the basalmost symphytan family amber from New Jersey8 (Engel, 2000b). Xyelidae. No apocritan lineage has been Cretotrigona is a derived apine of the tribe found prior to the Jurassic. Bees simply Meliponini (Apidae: Apinae). Thus, the clad- could not have been present in the Triassic ogenetic events that produced all of the lin- since no apocritans or even advanced wood eages between the origin of bees and the wasps had yet originated. Likewise, in Juras- branch that eventually gave rise to the me- sic deposits the known hymenopterans are liponines must have taken place prior to the basal apocritan lineages, a diversity of sym- Late Cretaceous. If a cladogram of bee fam- phytans, and a single plesiomorphic family ilies is overlayed on the geological column of aculeates. The earliest aculeate fossils are and the oldest possible age for bees assumed of the extinct family Bethylonymidae from (®g. 121), then the diversi®cation of bees the Uppermost Jurassic of Kazakhstan (Ras- into higher lineages must have coincided nitsyn, 1975) considered to be the sister with the angiosperm radiations that took group to all other aculeates (Rasnitsyn, 1988; place from 130±90 Ma (Crane et al., 1995), Ronquist et al., 1999). All other aculeates in with a particularly dramatic increase in ge- the fossil record have their ®rst appearance neric diversity 115±90 Ma (Lidgard and in the Cretaceous. Moreover, the earliest Crane, 1988; Crane and Lidgard, 1990). members of the Apoidea are plesiomorphic Even if the bees are somewhat younger than spheciform wasps in Lower Cretaceous sed- the 125 Ma date hypothesized here, they still iments of Brazil, Europe, and Central Asia. must have radiated prior to the Late Creta- No single specimen has been found of a ceous [simply owing to the presence of Cre- more advanced spheciform lineage (e.g., totrigona and the existence of plants today Crabronidae) prior to the Early Cretaceous. tightly associated with Apinae in 90 Ma de- As mentioned above, bees are a derived, posits (Crepet and Nixon, 1998)]. Thus, the monophyletic group arising from the para- window for both the origin and early diver- phyletic assemblage of spheciform families si®cation of bees into higher lineages lies be- in the Apoidea. Bees, therefore, must have tween ca. 125 Ma and 100 Ma. This period originated after the earliest spheciforms. of diversi®cation for bees accords nicely Since spheciforms (and thereby the entire su- with similar periods in the evolution of de- perfamily Apoidea) did not appear until the rived ¯oral characters associated with insect Cretaceous, bees must have originated in the pollination (Crepet, 1996). There is, at pre- Cretaceous. If one prefers to argue for the oldest possible age of bees, then the upper- 8 The Cretaceous age of this amber was questioned by most boundary for their age is the earliest Rasnitsyn (In Rasnitsyn and Michener, 1991) and considered to be Paleocene. Grimaldi (1999), however, has part of the mid-Cretaceous, or about 125 Ma. argued convincingly for a Cretaceous age of this deposit This automatically places the origin of bees and the Late Maastrichtian age (65±70 Ma) is adopted after the origin of angiosperms, which them- here [see also Engel (2000b)]. 2001 ENGEL: BALTIC AMBER BEES 153

Fig. 121. Phylogeny of bee families overlaid on the geological column. The shaded area indicates the period of angiosperm diversi®cation. Although ¯owering plants originated earlier than the shaded area indicates, the geological record does not show a dramatic increase in angiosperm diversity until when ®rst indicated in the ®gure. sent, no escape from the conclusion that bees an (Elliott and Nations, 1998) to the earliest radiated along with angiosperms in the Cre- Paleocene (e.g., Genise and Bown, 1996; taceous. Genise and Hazeldine, 1998; Genise, 1999; As just discussed, bee body fossils are Genise and Verde, 2000). The depth and total presently known only as far back as the number of cells in some of these nests were Maastrichtian (Engel, 2000b). Trace fossils taken as evidence for social behavior (e.g., believed to be the product of bees are known Elliott and Nations, 1998) but as mentioned from a variety of localities but the most no- above such attributes are not correlated with table for the discussion here are those from sociality in living bees and solitary bees can desposits ranging from the latest Cenomani- dig remarkably deep and large nests. It 154 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 would be impossible to state, based on nest sizes in Uruguay auroranormae Roselli are design, whether any of these presumed tra- from 12±15 mm (Genise and Bown, 1996)]; cemakers (if indeed bees) were social. The 2. the thickness of cell walls is quite variable identity of most of these traces is suspect but in halictines, and the most distinct thickenen- a fewÐsuch as the ichnogenus Uruguay ing of the walls in Uruguay are at the cell (Roselli, 1938)Ðare clearly the product of apex, a feature typical in nests where the bee activity. Thus, trace fossils do provide cells are reused; for example, in Pseudau- some, albeit limited, information for docu- gochlora where cells in a cell-cluster are re- menting Cretaceous bees. The Late Maas- used, the bees ®ll in more soil mostly at the trichtian (although perhaps earliest Paleo- apex of the old cell and to a lesser degree on cene) ichnogenus Uruguay is remarkably the sides before applying a new cell lining similar to cell-cluster nests of halictid bees, (Michener and Lange, 1958), resulting in a and those of the tribe Augochlorini in partic- similar cell construction to that of the trace- ular [this based on a cladistic reconstruction fossil; and 3. spiral closures are well known of nest architecture known for living Augo- in halictines, albeit less conspicuous in some chlorini Engel (1998b: also summarized brief- species (Sakagami and Michener, 1962). The ly in Engel, 2000a), which reconstructed a possibility remains that Uruguay is the oldest groundplan design for the tribe that included evidence of sweat bee activity. If indeed the cell-clusters]. Although another feature con- products of bees (perhaps also Halictinae), cluded to be plesiomorphic to the tribe was then the fossilized nests described by Elliott semisocial behavior, this determination was and Nations (1998) would be the oldest re- based merely on the distribution of sociobio- cord of bees presently known (ca. 92 Ma), logical attributes of Recent species and not as well as superceding Uruguay as the oldest on correlated aspects of their nest architec- record for Halictinae. Ichnology contributes ture (Engel, 1998b, 2000a). At that time the important information for understanding the augochlorines were hypothesized to be at evolutionary history of particular taxa. The least 75±80 Ma and to have originated from uni®cation of paleontology and paleoichnol- regions today in southern South America; ogy will undoubtedly be increasingly impor- thus, there is a tantalizing correlation be- tant in the future for elucidating the evolution tween the reconstructed groundplan nest de- of bees (Genise and Engel, 2000). sign for Augochlorini and the structure of Although the region of bee origination and Uruguay. It is possible that the tracemakers diversi®cation is speculative, the xeric inte- may not have been primitive Augochlorini rior of western Gondwanaland (southern but neither should augochlorines be excluded South America, Africa, and portions of Ant- as a likely candidate. Genise and Verde arctica) is most likely to have been the area (2000) dismissed the augochlorine hypothe- from which they arose. Today, bees and sis for these cells, concluding that ``. . . Uru- spheciform wasps, particularly the basal guay cannot be attributed to sweat bees be- groups of most families, are most abundant cause of its size, thickened walls, spiral clo- and diverse in such xeric habitats (although sures and other features''. In actuality, none clear exceptions do occur in some subfami- of these can exclude the possibility of sweat lies). This pattern of xeric-concentrated di- bees for the following reasons: 1. it is true versity is also true for the Masarinae and ma- that for typical sweat bees, such as Dialictus jor pollinating ¯ies (Gess, 1996; Grimaldi, (tribe Gastrohalictini), the cell sizes of Uru- 1999). A rudimentary cladistic reconstruc- guay are too large; however, the cell sizes are tion of habitat preference among bees would ample for the more robust augochlorines predict a distributional restriction to xeric re- (e.g., Pseudaugochlora, Megommation, some gions for the ancestor of all Apiformes. This Augochloropsis, some Rhinocorynura, &c.); is congruent with the hypothesis that the ®rst moreover, several of these species are known angiosperms were decumbent herbaceous to produce cell clusters [(of cell-cluster-pro- plants (Taylor and Hickey, 1992) and that the ducing Augochlorini, cell sizes can range climate in the Cretaceous was generally drier from 8 mm up to at least 21 mm (Sakagami than today (Spicer et al., 1993). Flowering and Michener, 1962), while the range of cell plants themselves likely originated (although 2001 ENGEL: BALTIC AMBER BEES 155 at an earlier date) in these xeric regions (Ra- pattern. However, the most plesiomorphic li- ven and Axelrod, 1974; Taylor and Hickey, thurgine, P. ditomeus (see Cladistic Analyses 1992). Associating this hypothesized ances- above), is present in Baltic amber indicating tral bee habitat with the supposed area of extinct, basal lineages that were once more origination for angiosperms implicates west- globally distributed. Extinction has certainly ern Gondwanaland as the most likely region- been a signi®cant factor in bee evolution and al candidate. As hypothesized by Grimaldi must be taken into consideration when at- (1999), the signi®cant xeric diversity of pol- tempting to explain present day distributions linating insects (including bees) may repre- (refer also to Grande, 1985; Grimaldi, 1992). sent Cretaceous ``refugia''. That the most There is a possible taphonomic outcome plesiomorphic and presumably ancient bees of the original habitat preference of bees that of the paraphyletic subfamily Colletinae are may pose dif®culties when trying to locate most diverse in temperate South America mid-Cretaceous fossils. If bees originated in and Australia is perhaps indicative of this xeric regions and subsequently invaded more origination in Gondwanaland (colletines are forested and tropical habitats, then it may be- also represented in southern Africa by Col- come increasingly dif®cult to ®nd older bee letes and Scrapter, but to a much lesser de- fossils in amber since these are not the pa- gree than elsewhere). It is perhaps also sig- leoenvironments thought to eventually pro- ni®cant that many basal groups of the various duce amber deposits. The original bees may families show globally disjunct or, in some simply not have occurred in regions where cases, primarily Gondwanan distributions. amber was being formed. If this is the case, For example, aside from Colletinae, there are then there will be a heavy reliance on com- the subfamilies of Halictidae (themselves pression fossils for locating the earliest bees. each likely ancient) that perhaps originated Furthermore, the minute details needed to early and subsequently diversi®ed in differ- distinguish an early bee from a spheciform ent regions. The Andreninae are found most- wasp would perhaps be hard to discern in a ly in the Laurasian continents and perhaps mid-Cretaceous amber inclusion. Such a dis- diversi®ed there after having moved out of tinction among taxa may be overwhelmingly western Gondwanaland. The remaining basal dif®cult even in the ®nest of compression subfamilies of Andrenidae and basal tribes of fossils. Therefore, it may become increasing- Panurginae are southern in distribution (the ly challenging to piece together progressively subfamily Euherbstiinae is the sole represen- more ancient bee faunas. tative of non-panurgine andreninds in south- How the transition from a prey-hunting ern South America with Alocandreninae spheciform wasp to vegetarian bee took slightly farther north in Peru). The Panurgi- place is, of course, entirely conjectural. De- nae are diverse in xeric regions and the Old spite our inability to ever know how such a World tribes (i.e., Panurgini, Melitturgini, signi®cant evolutionary transition might and Meliturgulini) perhaps invaded through have unfolded, it is interesting to speculate Africa during the breakup of the continents on this event as well as those groundplan fea- and then subsequently returned to western tures most likely to have characterized the North America in the Tertiary (i.e., within Urbiene or ``proto-bee''. Several authors the Panurgini). Primitive megachilids of the have hypothesized about the traits of the Fideliinae (which occur in southern South ``proto-bee'' with varying degrees of specu- America and southern Africa except for one lation on processes (e.g., Malyshev, 1968; species in Morocco) and Xylocopinae in the Radchenko and Pesenko, 1994a, 1994b, Apidae also demonstrate similar patterns of 1996; Michener, 2000a, 2000b). The follow- diversity. These patterns, however, must be ing account presented herein is generally in taken with caution since some of these accord with most of those prior views and I groups may have been once more diverse have therefore kept this discussion and my than they are today. For instance, on the basis speculative scenarios to a minimum. of living taxa alone, the Lithurginae, with By undertaking a cladistic reconstruction basal living groups most diverse in temperate for the Apiformes (®gs. 122, 123) it is pos- South America, would appear to hold this sible to obtain a generalized picture of the 156 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Fig. 122. Phylogeny of the bees (short-tongued bee families). groundplan morphological and biological at- glossinae, and Xeromelissinae is likely not to tributes that were likely present in the ances- be plesiomorphic for this family nor from tor of all bees. The Colletidae are indeed the where groundplan traits of all bees should be most basal family of the Apiformes (®gs. sought. As alluded to above, the subfamily 121, 122) but the clade consisting of the Colletinae as it is presently constituted is ``wasp-like'' subfamilies Hylaeinae, Eury- very likely paraphyletic not only to Stenotri- 2001 ENGEL: BALTIC AMBER BEES 157

Fig. 123. Phylogeny of the bees (long-tongued bee families). 158 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 tinae and Diphaglossinae but also to the Hy- risk of death to the provisioning female from laeinae ϩ Euryglossinae ϩ Xeromelissinae those prey that might ®ght back would be clade. Presently, relationships among the immediately given up. Such presumably several genera of Colletinae are not entirely strong selective pressures in this scenario clear so I have avoided splitting the subfam- would quickly result in any such lineage of ily apart for the time being. Some genera, wasps to become vegetarian. The plumose such as Scrapter and Callomelitta, may setae, a distinguishing trait of bees, were prove to be more closely related to the latter likely not an original adaptation for the trans- three subfamilies as well as Colletes, while port of pollen. Plumose setae were perhaps, the stenotritines may be sister to a clade of as discussed by Michener (2000a), a means Australian colletines (e.g., some Paracolleti- of conserving water in an arid environment. ni), thereby rendering Colletinae with its cur- Branched setae are not a necessity for the rent composition paraphyletic to all other transport of pollen since many bees have colletids (see also McGinley, 1981). The in- simple scopal setae. As mentioned above, ternal phylogeny of Colletidae, however, is bees likely arose in the xeric interior of in need of clari®cation and any discussion Gondwanaland and plumose setae would po- (including the one presented herein) of the tentially have been a novel mechanism for ``proto-bee'' must be considered as tentative. decreasing integumental evaporation (in con- By this account, however, the general wasp- trast to simply increasing the total number of like features of hylaeines and euryglossines setae). As also pointed out by Michener (e.g., reduced scopae) are apomorphic for (2000a), that such setae are generally pale this colletid clade and not plesiomorphic for (white or off-white) and are a groundplan bees. Thus, groundplan features for the bees feature for the bees is also suggestive since should be derived from plesiomorphic traits many xeric-environment insects presumably of the Colletinae, Halictidae, and Andrenidae use pale hue to re¯ect heat and as protective as well as the remaining families. From these coloration. As just mentioned, pilosity serves considerations the ``proto-bee'' was a rela- a thermoregulatory function (e.g., Church, tively robust, moderately pubescent, short- 1960). In hovering and other strong ¯ying, tongued apoid with a broad glossa. Pollen pollinating insects, like bees and bee¯ies, would have been carried externally on the thick pilosity also serves to maintain a high body and not within the crop (as is done by body temperature, especially as ¯ight begins species of Hylaeinae and Euryglossinae). after torpor from cold, desert nights. Clearly, Ground-nesting is a groundplan feature of some desert bees have minimal setae (e.g., each family and thereby of the bees as a some Xylocopa) but those that ¯y earlier in whole; the ``proto-bee'' would have therefore the morning tend to be more setose. Plumose constructed simple burrows in the soil. The setae in the ``proto-bee'' likely played a role stem-group wasps from which the ``proto- in thermoregulation and water conservation bee'' itself arose would have nested in the rather than in pollen transport. soil (such a reconstruction based on the fea- The major lineages of bees (i.e., families, tures of the spheciform wasps is well sup- perhaps some subfamilies) perhaps diversi- ported). Such wasps would perhaps have ®ed rapidly shortly following the origin of brought back pollen-covered prey that fe- bees as a whole (®gs. 121±123). The division males had captured on early ¯owering plants. into those ancestral lineages that eventually Once the wasp larva had by chance become gave rise to the various families recognized able to digest and make use of the pollen as today must have taken place sometime be- a protein resource, it was perhaps not long tween 125±90 Ma. These families then pro- before pollen became the primary, if not sole, gressed along independent evolutionary source of food. A female wasp would have tracks, undoubtedly with numerous groups a decreased search-time for provisions owing that exhibited interesting character combi- to the fact that ¯owers advertise themselves nations becoming extinct at various stages for pollination and are stationary while prey (and as is documented above, several by the attempt to hide and are mobile. Moreover, latest Eocene at least since only modern negative consequences such as injury and groups are known in the Oligocene and 2001 ENGEL: BALTIC AMBER BEES 159

younger deposits), leaving the six families THE EOCENE BEE FAUNA we recognize today. The family Paleomelit- tidae represents one such `ìntermingled'' lin- A general pattern of af®nity between the eage whose extinction left large character Eocene fauna of Europe and the present day faunas of Asia and sub-Saharan Africa is gaps between the surviving lineages. Such documented for various groups (e.g., Ander, extinct lineages were perhaps dwindling by 1942; Larsson, 1978). For example, the fa- middle Eocene times. At present there should mous Baltic amber lizard has af®nities to be little or no concern for the absence of a groups in Africa and was even assigned, until tight correlation between the stratigraphic recently, to the living African genus Nucras ranks and phylogenetic ranks of bee taxa. (BoÈhme and Weitschat, 1998). Likewise, the Signi®cant correlations have been found in a Baltic amber scorpion Palaeolychras balti- variety of taxa where the fossil record is rel- cus LourencËo and Weitschat has as its nearest atively well represented and cladograms are relative a genus presently occurring in Africa well resolved (e.g., Norell and Novacek, and southern Asia (LourencËo and Weitschat, 1992a, b; Borkent, 1995; Grimaldi and Cum- 1996). A similar pattern certainly holds true ming, 1999). For the bees, however, the fos- for the Baltic amber bees. The Borealloda- sil record is comparatively sparse, with geo- pini is allied to the Allodapini, a tribe that logical data points based on limitations: 1. in has its greatest diversity in sub-Saharan Af- number of well preserved specimens upon rica, southeast Asia, and Australia (see also which to base character analyses; 2. in chro- discussion above under Cladistic Analyses). nological diversity and number of horizons The genera Kelneriapis, Liotrigonopsis, and with identi®able bee specimens (only a few, Electrolictus are all most similar and certain- scattered deposits have at present revealed ly related to genera today occurring in Africa fossil bees); 3. in diversity and number of and southeast Asia (namely Hypotrigona, higher-level lineages (e.g., tribes) with a fos- Liotrigona, and Patellapis, respectively). sil record of any sort [e.g., see appendix 2, Similarly, the Melikertini is sister to Meli- where of 83 suprageneric groups (not includ- ponini, a group that is today pantropical in ing subtribes) only 28 are represented in the distribution and the Glyptapina have af®ni- fossil record, and most of these are based on ties with the Old World (principally African) dubiously assigned compression fossils (per- Anthidiini. sonal obs.)]; and 4. in number of cladistic The bee fauna of the Baltic amber is analyses for bee groups. unique, with a wider array of bees than any Although bees are quite rare as amber in- other LagerstaÈtte in the world. The fauna is clusions (except for the common Proplebeia further important for the preservation of a dominicana in Dominican amber), the explo- number of primitive, higher groups that failed to survive to the present day. This is ration of Cretaceous amber sites for older in sharp contrast to younger fossil faunas bees is imperative, no matter how seemingly from the Oligocene or Miocene where spe- futile. Compression fossils will also play an cies belong to extant genera or extinct genera important, albeit somewhat more limited, closely related to modern groups and in all role in understanding bee evolution and may cases to living tribes, subfamilies, and fami- eventually prove to be critical for under- lies (e.g., lowest Miocene Dominican amber: standing the earliest of bees. Such explora- table 1; Oligocene of Germany: Engel, tion of the Cretaceous will hopefully bring 1998c). It is possible that some of the extinct to science additional lineages that close the lineages from the Baltic amber fauna are the gaps in our knowledge and help us to further ®nal Tertiary survivors of originally Meso- re®ne the scenario of bee diversi®cation I zoic bee lineages. Owing to the presence of have presented. It is from such Mesozoic fos- a meliponine in latest Cretaceous amber (En- sils (particularly those preserved in amber) gel, 2000b), this is almost certainly the case that the greatest contributions will come for for the tribes Electrobombini, Electrapini, not only understanding bee origins but for and Melikertini as well as the Paleomelitti- reconstructing the pattern of bee phylogeny. dae. The almost modern character of the only 160 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 halictine in the Baltic amber fauna, Electrol- whole became very modern at this period. ictus, is indicative of not only this tribe's an- This is noteworthy since the success, as mea- tiquity, but of that for the whole family. sured by ecological dominance and speci®c From the available paleomelittological infor- diversity, of groups such as the termites (ca. mation it would appear that the bees under- 3,000 species), ants (ca. 16,000 species), and went at least two periods of diversi®cation. social wasps (ca. 1,000 species) has been di- The ®rst was either at their origin or shortly rectly attributed to their advanced eusocial thereafter and produced the array of taxa that behavior. The bees have been understandably eventually gave rise to families we recognize included with these lineages since bees are today. The second radiation appears to have undoubtedly more diverse than all three com- been in the Tertiary. As mentioned repeat- bined and arguably more ecologically dom- edly above, those taxa from the Eocene and inant owing to their role as the most signif- earlier all belong to extinct genera and, icant pollinators of angiosperms. Bees as a where information is available, most belong whole, however, are mostly solitary, while to higher categories (i.e., tribes, subfamilies, the advanced eusocial lineages (all restricted and families) that are no longer extant. Im- to the corbiculate Apinae) account for merely mediately following the Eocene and by the ca. 380 species. Not surprisingly, pollination earliest Miocene the bee fauna becomes re- has likely driven the overall speci®c diversity markably modern in appearance, with most of bees but counter-intuitively, it appears that fossils belonging to living genera. There are advanced eusocial behavior has not further no extinct suprageneric lineages in Oligocene fueled diversity in those lineages where it has or younger deposits. The bees in the Eocene arisen. In fact, it could even be argued that and perhaps older deposits were presumably such highly organized and ecologically ag- remnants of originally Cretaceous diversi®- gressive societies have hindered the speci®c cations. At the end of the Eocene those enig- diversity of the corbiculate bees over geolog- matic higher lineages were perhaps dwin- ical time. Advanced eusocial species, like the dling and, at least in Europe, their eventual western honey bee, Apis mellifera, are disappearance was possibly aided by the known to in¯uence the foraging patterns and changing global climate at the time. Thus, at abundance of other species through compe- the Eocene-Oligocene transition there was a tition for resources (Eickwort and Ginsberg, dramatic shift in the tribal composition of the 1980; Wenner and Thorp, 1994; Buchmann, bee fauna to entirely modern tribes and es- 1996). The diversity of native bees has been sentially modern genera that either originated negatively impacted, including that of other or ®rst experienced their greatest radiation at advanced eusocial lineages, in areas where A. that time. Thus, the bee fauna we are familiar mellifera has been introduced (e.g., Roubik with today appears to have had its compo- et al., 1986; Sugden et al., 1996). This neg- sitional origin in the Oligocene Epoch. ative interaction is intense enough that ex- It is signi®cant that there is such a re- tinction of stingless bee colonies was one of markable diversity of advanced eusocial cor- the predicted likely outcomes of the compet- biculate bees in the Eocene fauna and more itive interactions between introduced honey so that most of these taxa represent higher bees and native Meliponini (Roubik et al., lineages that have since become extinct (En- 1986). Introduced honey bees not only neg- gel, in press-b). A general, epoch-by-epoch atively affect native bees but also nectar- overview of the geological history of the cor- feeding bird populations (Paton, 1993). Even biculate Apinae (e.g., Engel, 2000c) shows a amongst the living honey bees it has been decrease in diversity at higher categorical observed that introduced populations of A. levels (e.g., genera and tribes), particularly mellifera aggressively displace A. cerana between the Eocene and Oligocene Epochs. (e.g., Sakagami, 1959). Interestingly, in Apis, During this transition period numerous tribes the most ecologically dominant and aggres- and genera of advanced eusocial lineages sive eusocial group, the speci®c diversity is disappeared so that by the Oligocene the cor- at its lowest for any advanced eusocial line- biculate bee fauna was essentially modern in age (Engel, 1999c). The generally less ag- character and, in fact, the bee fauna as a gressive Meliponini are not only more spe- 2001 ENGEL: BALTIC AMBER BEES 161 ciose than Apini, but the tribe is most diverse ancient ecologies, patterns of evolution, and in regions where Apis species are not native past epochs of life on Earth. (i.e., South and Central America). It is possible that over more expansive reaches of ACKNOWLEDGMENTS time such ecologically dominant foragers This work would not have been possible have had a more devastating impact on not without the generous support of Robert G. only non-social species but also and perhaps Goelet, Chairman Emeritus of the AMNH especially on other advanced eusocial line- Board of Trustees. I am sincerely grateful for ages that were not as ef®cient competitors. his patronage and admirable support of col- Certainly, extrinsic factors have played a role lections-based research. Jerome G. Rozen, in the diversity and distribution of bees and Jr., has been a close mentor and friend as continued paleontological work throughout the world will contribute to either supporting well as serving as a sounding board during or refuting this hypothesis. the past two years for ideas presented herein. Charles D. Michener continually provided support and advice; I am particularly grateful EPILOGUE for his time and patience during my visits to The study of amber inclusions allows the discuss fossils, phylogeny, and evolutionary scientist to peer directly into past eons with trends in bees. David A. Grimaldi has enthu- far greater clarity than is possible from other siastically supported my work in paleoento- kinds of fossils. In the case of the present mology, giving access to equipment, funds, work, these tiny bees, perhaps guards from and supplies, as well as providing valuable some ancient colonies, have waited attenta- advice and friendship. Molly G. Rightmyer tively while 45 million years of history masterfully executed the numerous line illus- passed in review. Arriving in life-like form, trations in this monograph; her patient and surviving untold geological turmoil, these meticulously careful work has greatly en- tiny mummies have opened a window onto hanced the presentation of this material. a world since lost, utterly reshaping our My work also has been greatly facilitated knowledge of bee evolution. I must admit to by assistance and/or advice received either sharing the sentiment expressed by Rev. formally, during visits to foreign institutions, Hope (1836), who, in regard to his own study or during casual discussions from Alger G. of Baltic amber insects, wrote (p. 137): Engel, Donna G. Engel, Hans Jahnke, Jan Koteja, Kumar Krishna, Valerie Krishna, Let then the geologist boast of his Mastodon and Me- Malcolm C. McKenna, Paul Nascimbene, gatherium, his wondrous Saurian Reptiles, and numerous genera of unknown beings; the entomologist also Tam C. Nguyen, Michael Ohl, Erika Pie- prides himself on his Amber Insects, ..., surpassing trzeniuk, Andrew J. Ross, and Wolfgang them in beauty and in colouring. Let the former add Weitschat. This monograph would have been room to room, gallery to gallery, and ®ll a city with far less fruitful had it not been for the gen- his relics and his casts, the latter may also rest con- erosity of the private collectors listed on pp. tented with his stores, less bulky indeed although not less interesting. The earth is a study for them both, an 17±18 (Material and Methods) who patiently inexhaustible ®eld of inquiry, and it may be a matter allowed me to study their specimens; I am of question which will most contribute to illustrate the sincerely grateful to each. Barbara Kosmows- condition and character of its earliest tenants. ka-Ceranowicz kindly supplied copies of her Both the `Àge of Dinosaurs'' and `Àge work and Wolfgang Weitschat copies of re- of Mammals'', periods frequently referred to cent work on Baltic amber stratigraphy and by scientists and laymen alike, are eclipsed dating; the latter also acted as courier for nu- by an Age of Insects. From the late Paleozoic merous specimens from private collections. to the present day, insects have dominated Although I could not agree with his conclu- terrestrial and freshwater ecosystems. A pa- sions, I am appreciative to Stephen T. Hasi- leontological perspective of insect diversity otis for generously supplying copies of his will, therefore, provide a powerful comple- work concerning trace fossils in North Amer- ment, if not in some instances a more sig- ica. JoÈrg Wunderlich, Jens von Holt, and ni®cant component, to the reconstruction of Bernard Striebich made Baltic amber bees 162 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259 available to the AMNH and myself; their Anderson, K. B., and B. A. LePage support and interest was of great value. Last- 1995. Analysis of fossil resins from Axel Hei- ly, I am thankful to Michael Ohl and his fam- berg Island, Canadian Arctic. In K. B. ily for kindly hosting my stay in Berlin, Er- Anderson and J. C. Crelling (eds.), Am- ika Pietrzeniuk for assistance while in the In- ber, Resinite, and Fossil Resins: 170± 192. Washington DC: Am. Chem. Soc. stitut fuÈr PalaÈontologie (Berlin), Hans Jahnke Arillo, A., A. Nel, and V. M. OrtunÄo for providing lodging and assistance in the 1996. Two fossil bees from the Oligocene of Institut und Museum fuÈr Geologie und Pa- Izarra (Alava, Spain) (Hymenoptera, laÈontologie (GoÈttingen), and to Kumar and Apoidea). Bull. Soc. Entomol. France Valerie Krishna for graciously hosting me 101: 59±64. during my stay in London. Oliver C. Phillips Armbruster, L. and Stanley Lombardo, of the University of 1938. Versteinerte Honigbienen aus dem ob- Kansas Classics Department, kindly helped ermiocaÈnen Randecker Maar. Arch. Bi- with Latin translations. enenkd. 19: 1±48, 97±133. I am enormously indebted to Lee Herman, Arroyo, M. T. K., P. Primack, and J. Armesto Brenda Jones, and Robert Voss for their help 1982. Community studies in pollination ecology in the high Andes of central Chile. with the publication of my manuscript. The 1. Pollination mechanisms and altitu- manuscript received critiques from David A. dinal variation. Am. J. Bot. 69: 82±97. Grimaldi, Lee Herman, Zhiwei Liu, Charles Bachmayer, F., N. Symeonidis, and D. Theodo- D. Michener, Molly G. Rightmyer, Jerome G. ropoulos Rozen, Jr., and two anonymous reviewers. I 1971. Einige Insektenreste aus den Jungterti- am grateful to each for their time and pa- aÈren SuÈsswasserablagerungen von Kumi tience. Not all agreed with my conclusions (Insel Euboea, Griechenland). Ann. Geol. and any remaining errors or peculiar inter- Pays Helleniques 23: 165±174. pretations are, naturally, my own. Bachofen-Echt, A. 1949. Der Bernstein und seine EinschluÈsse. Vienna: Springer Verlag KG. REFERENCES Bawa, K. S. (Journal abbreviations are spelled out in appen- 1990. Plant-pollinator interactions in tropical dix 4.) rain forests. Annu. Rev. Ecol. Syst. 21: 399±422. Alexander, B. A. Bawa, K. S., S. H. Bullock, D. R. Perry, R. E. 1992. An exploratory analysis of cladistic re- Coville, and M. H. Grayson lationships within the superfamily Apo- 1985. Reproductive biology of tropical low- idea, with special reference to sphecid land rain forests. II. Pollination sys- wasps (Hymenoptera). J. Hym. Res. 1: tems. Am. J. Bot. 72: 346±351. 25±61. Beck, C. W. Alexander, B. A., and C. D. Michener 1986. Spectroscopic investigations of amber. 1995. Phylogenetic studies of the families of Appl. Spectrosc. Rev. 22: 57±110. short-tongued bees (Hymenoptera: Beck, C. W., E. Wilbur, and S. Meret Apoidea). Univ. Kansas Sci. Bull. 55: 1964. Infrared spectra and the origin of am- 377±424. ber. Nature 201: 256±257. Alexander, B. A., C. D. Michener, and A. L. Gard- Beck, C. W., E. Wilbur, S. Meret, D. Kossove, and ner K. Kermani 1998. Dasypodidae BoÈrner, 1919 (Insecta, 1965. The infrared spectra of amber and the Hymenoptera): Proposed emendation identi®cation of Baltic amber. Archaeo- of spelling to Dasypodaidae, so remov- metry 8: 96±109. ing the homonymy with Dasypodidae Bischoff, H. Gray, 1821 (Mammalia, Xenarthra). 1927. Biologie der Hymenopteren: Eine Na- Bull. Zool. Nomencl. 55: 24±28. turgeschichte der Haut¯uÈgler. Berlin: Ander, K. Springer Verlag. 1942. Die Insektenfauna des baltischen Bern- BoÈhme, W., and W. Weitschat steins nebst damit verknuÈpften zoogeo- 1998. Redescription of the Eocene lacertid liz- graphischen Problemen. Lunds Univ. ard Nucras succinea Boulenger, 1917 AÊ rskr., 2 Afd. 38: 1±83. from Baltic amber and its allocation to 2001 ENGEL: BALTIC AMBER BEES 163

Succinilacerta n.gen. Mitt. Geol.-PalaÈon- Meliponinae). Biol. J. Linn. Soc. 44: tol. Inst. Univ. Hambg. 81: 203±222. 13±39. Borkent, A. Camargo, J. M. F., W. E. Kerr, and C. R. Lopes 1995. Biting Midges in the Cretaceous Amber 1967. Morfologia externa de Melipona (Me- of North America (Diptera: Ceratopo- lipona) marginata Lepeletier (Hyme- gonidae). Leiden: Backhuys. noptera: Apoidea). Pap. Avulsos Zool. BoÈrner, C. (SaÄo Paulo) 20: 229±258. 1919. Stammesgeschichte der Haut¯uÈgler. Biol. Camargo, J. M. F., D. A. Grimaldi, and S. R. M. Zentbl. 39: 145±186. Pedro Bour, R., and A. Dubois 2000. The extinct fauna of stingless bees (Hy- 1984. Nomenclature ordinale et familiale des menoptera: Apidae: Meliponini) in Do- tortues (Reptilia). Stud. Geol. Salmanti- minican amber: Two new species and censia (Stud. Palaeocheloniol.) 1: 77±86. redescription of the male of Proplebeia Brischke, D. dominicana (Wille and Chandler). Am. 1886. Die Hymenopteren des Bernsteins. Mus. Novitates 3293: 24 pp. Schr. Naturf. Gesell. Danzig 6: 278± Cameron, S. A. 279. 1991. Brothers, D. J. A new tribal phylogeny of the Apidae 1975. Phylogeny and classi®cation of the acu- inferred from mitochondrial DNA se- leate Hymenoptera, with special refer- quences. In D. R. Smith (ed.), Diversity ence to Mutillidae. Univ. Kansas Sci. in the Genus Apis: 71±87. Boulder CO: Bull. 50: 483±648. Westview Press. 1976. Modi®cations of the metapostnotum 1993. Multiple origins of advanced eusocial- and origin of the ``propodeal triangle'' ity in bees inferred from mitochondrial in Hymenoptera Aculeata. Syst. Ento- DNA sequences. Proc. Natl. Acad. Sci., mol. 1: 177±182. U.S.A. 90: 8687±8691. 1999. Phylogeny and evolution of wasps, ants Carpenter, K. and bees (Hymenoptera, Chrysidoidea, 1992. Behavior of hadrosaurs as interpreted Vespoidea and Apoidea). Zool. Scr. 28: from footprints in the ``Mesaverde'' 233±249. Group (Campanian) of Colorado, Utah, Brothers, D. J., and J. M. Carpenter and Wyoming. Contrib. Geol., Univ. 1993. Phylogeny of Aculeata: Chrysidoidea Wyoming 1992: 81±96. and Vespoidea (Hymenoptera). J. Hym. Carroll, E. J. Res. 2: 227±304. 1962. Mesozoic fossil insects from Koonwar- Buchmann, S. L., and G. P. Nabhan ra, South Gippsland, Victoria. Aust. J. 1996. The Forgotten Pollinators. Washington Sci. 25: 264±265. DC: Island Press. ChavarrõÂa, G., and J. M. Carpenter Burmeister, H. 1994. ``Total evidence'' and the evolution of 1831. Handbuch der Entomologie: Erste highly social bees. Cladistics 10: 229± Band: Allgemeine Entomologie. Berlin: 258. G. Reimer. Church, N. S. 1832. A Manual of Entomology. London: E. 1960. Heat loss and body temperature of ¯y- Churton. [Translation of Burmeister, ing insects. I. Heat loss by evaporation 1831] Burnham, L. of water from the body. II. Heat con- 1978. Survey of social insects in the fossil reduction within the body and its loss by cord. Psyche 85: 85±133. radiation and convection. J. Exp. Biol. Buttel-Reepen, H., von 37: 171±212. 1906. Apistica. BeitraÈge zur Systematik, Biol- Clark, J. M., M. A. Norell, and L. M. Chiappe ogie, sowie zur geschichtlichen und 1999. An oviraptorid skeleton from the Late geographischen Verbreitung der Hon- Cretaceous of Ukhaa Tolgod, Mongo- igbiene (Apis melli®ca L.), ihrer Var- lia, preserved in an avianlike brooding ietaÈten und der uÈberigen Apis-Arten. position over an oviraptorid nest. Am. Mitt. Zool. Mus. Berl. 3: 117±201. Mus. Novitates 3265: 36 pp. Camargo, J. M. F., and D. W. Roubik Cockerell, T. D. A. 1991. Systematics and bionomics of the apoid 1906. Fossil Hymenoptera from Florissant, obligate necrophages: The Trigona hy- Colorado. Bull. Mus. Comp. Zool. 50: pogea group (Hymenoptera: Apidae; 33±58. 164 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

1907. A fossil honey-bee. Entomol. 40: 227± Crane P. R., and S. Lidgard 229. 1990. Angiosperm radiation and patterns of 1908a. Descriptions and records of beesÐ Cretaceous palynological diversity. In XIX. Ann. Mag. Nat. Hist., ser. 8, 1: P. D. Taylor and G. P. Larwood (eds.), 337±344. Major Evolutionary Radiations: 377± 1908b. Descriptions and records of beesÐXX. 407. Oxford: Clarendon Press. Ann. Mag. Nat. Hist., ser. 8, 2: 323± Crane, P. R., E. M. Friis, and K. R. Pedersen 334. 1995. The origin and early diversi®cation of 1908c. A fossil leaf-cutting bee. Can. Entomol. angiosperms. Nature 374: 27±33. 40: 31±32. Crepet, W. L. 1909a. Some European fossil bees. Entomol. 1996. Timing in the evolution of derived ¯o- 42: 313±317. ral characters: Upper Cretaceous (Tu- 1909b. Descriptions of Hymenoptera from ronian) taxa with tricolpate and tricol- Baltic amber. Schr. Phys.-OÈ kon. Gesell. pate-derived pollen. Rev. Palaeobot. 50: 1±20. Palynol. 90: 339±359. 1909c. Some additional bees from Prussian Crepet, W. L., and K. C. Nixon amber. Schr. Phys.-OÈ kon. Gesell. 50: 1998. Fossil Clusiaceae from the Late Creta- 21±25. ceous (Turonian) of New Jersey and 1909d. Two fossil bees. Entomol. News 20: implications regarding the history of 159±161. bee pollination. Am. J. Bot. 85: 1122± 1909e. New North American bees. Can. En- 1133. tomol. 41: 393±395. Daly, H. V., C. D. Michener, J. S. Moure, and S. 1911a. Fossil insects from Florissant, Colora- F. Sakagami do. Bull. Am. Mus. Nat. Hist. 30: 71± 1987. The relictual bee genus Manuelia and 82. its relation to other Xylocopinae (Hy- 1911b. Descriptions and records of beesÐ menoptera: Apoidea). Pan-Pac. Ento- XXXIV. Ann. Mag. Nat. Hist., ser. 8, mol. 63: 102±124. 7: 225±237. Darling, D. C., and M. J. Sharkey 1913a. Some fossil insects from Florissant, 1990. Order Hymenoptera. In D. A. Grimaldi Colorado. Proc. U.S. Natl. Mus. 44: (ed.), Insects from the Santana Forma- 341±346. tion, Lower Cretaceous, of Brazil. Bull. 1913b. Some fossil insects from Florissant. Am. Mus. Nat. Hist. 195: 123±153. Can. Entomol. 45: 229±233. Donoghue, M. J., J. A. Doyle, J. Gauthier, A. G. 1914. Miocene fossil insects. Proc. Acad. Kluge, and T. Rowe Nat. Sci., Philadelphia 66: 634±648. 1989. The importance of fossils in phylogeny 1917. New Tertiary insects. Proc. U.S. Natl. reconstruction. Annu. Rev. Ecol. Syst. Mus. 52: 373±384. 20: 431±460. 1921. Fossil arthropods in the British Muse- Eickwort, G. C. um. Ann. Mag. Nat. Hist., ser. 9, 8: 1969. A comparative morphological study 541±545. and generic revision of the augochlor- 1923. Two fossil Hymenoptera from Floris- ine bees (Hymenoptera: Halictidae). sant (Vespidae, Megachilidae). Ento- Univ. Kansas Sci. Bull. 48: 325±524. mol. News 34: 270±271. Eickwort, G. C., and H. S. Ginsberg 1925. Descriptions and records of beesÐ 1980. Foraging and mating behavior in Apo- CVI. Ann. Mag. Nat. Hist., ser. 9, 16: idea. Annu. Rev. Entomol. 25: 421± 416±423. 446. 1930a. The bees of Australia. Aust. Zool. 6: Eickwort, G. C., and S. F. Sakagami 205±236. 1979. A classi®cation of nest architecture of 1930b. African bees of the family Ctenoplec- bees in the tribe Augochlorini (Hyme- tridae from the Belgian Congo and Li- noptera: Halictidae; Halictinae), with beria (Hymenoptera Apoidea). Rev. description of a Brazilian nest of Rhin- Zool. Bot. Africa 18: 358±363. ocorynura in¯aticeps. Biotropica 11: 1931. Insects from the Miocene (Latah) of 28±37. Washington, II. Hymenoptera and He- Eldredge, N., and M. J. Novacek miptera. Ann. Entomol. Soc. Am. 24: 1985. Systematics and paleontology. Paleo- 309±312. biology 11: 65±74. 2001 ENGEL: BALTIC AMBER BEES 165

Elliott, D. K., and J. D. Nations 2000b. A new interpretation of the oldest fossil 1998. Bee burrows in the Late Cretaceous bee (Hymenoptera: Apidae). Am. Mus. (Late Cenomanian) Dakota Formation, Novitates 3296: 11 pp. northeastern Arizona. Ichnos 5: 243± 2000c. Fossils and phylogeny: A paleontolog- 253. ical perspective on social bee evolu- Engel, M. S. tion. In M.M.G. Bitondi and K. Hart- 1995. Neocorynura electra, a new fossil bee felder (eds.), Anais do IV Encontro So- species from Dominican amber (Hy- bre Abelhas: 217±224. RibeiraÄo Preto: menoptera: Halictidae). J. New York Universidade de SaÄo Paulo. Entomol. Soc. 103: 317±323. [Publ. In press-a. The ®rst large carpenter bee from date: 5 November 1996] the Tertiary of North America, with a 1996. New augochlorine bees (Hymenoptera: consideration of the geological history Halictidae) in Dominican amber, with a of Xylocopinae (Hymenoptera: Api- brief review of fossil Halictidae. J. dae). Trans. Am. Entomol. Soc. Kansas Entomol. Soc., Suppl. 69: 334± In press-b. Monophyly and extensive extinc- 345. [Publ. date: 15 January 1997] tion of advanced eusocial bees: Insights 1998a. A new species of the Baltic amber bee from an unexpected Eocene diversity. genus Electrapis (Hymenoptera: Api- Proc. Natl. Acad. Sci., U.S.A. dae). J. Hym. Res. 7: 94±101. Engel, M. S., and M. G. Rightmyer 1998b. Phylogeny, classi®cation, and evolu- 2000. A new augochlorine bee species in Ter- tionary ethology of the bee tribe Au- tiary amber from the Dominican Re- gochlorini (Hymenoptera: Halictidae). public (Hymenoptera: Halictidae). Ap- Ph.D. diss., Cornell Univ., Ithaca, NY. idologie 31: 431±436. 1998c. Fossil honey bees and evolution in the Engel, M. S., and T. R. Schultz genus Apis (Hymenoptera: Apidae). 1997. Phylogeny and behavior in honey bees Apidologie 29: 265±281. (Hymenoptera: Apidae). Ann. Entomol. 1998d. Comparative morphology and the phy- Soc. Am. 90: 43±53. logeny of the corbiculate bees (Hyme- Epis, R. C., and C. E. Chapin 1974. Stratigraphic nomenclature of the Thir- noptera: Apidae; Apinae). Proc. 13th tynine Mile volcanic ®eld, central Col- Intl. Congr. IUSSI, Adelaide 1998: 151. orado. U.S. Geol. Surv. Bull., Washing- 1999a. Apis proava Menge, 1856 (currently ton 1395-C. Electrapis proava; Insecta, Hymenop- Foord, A. S. tera): Proposed conservation by desig- 1890. Note on a collection of east coast am- nation of a neotype. Bull. Zool. No- ber belonging to Mrs. Burwood of Yar- mencl. 56: 134±135. mouth. Trans. Norfolk Norwich Nat. 1999b. The ®rst fossil Euglossa and phylogeny Soc. 5: 92±95. of the orchid bees (Hymenoptera: Ap- Friese, H. idae; Euglossini). Am. Mus. Novitates 1903. Neue Meliponiden II. Z. Syst. Hym. 3272: 14 pp. Dipt. 3: 359±361. 1999c. The taxonomy of recent and fossil hon- Gauthier, J., A. G. Kluge, and T. Rowe ey bees (Hymenoptera: Apidae; Apis). 1989. Amniote phylogeny and the importance J. Hym. Res. 8: 165±196. of fossils. Cladistics 4: 105±209. 1999d. Megachile glaesaria, the ®rst megach- Genise, J. F. ilid bee fossil from amber (Hymenop- 1999. Fossil bee cells from the Asencio For- tera: Megachilidae). Am. Mus. Novi- mation (Late Cretaceous-Early Tertia- tates 3276: 13 pp. ry) of Uruguay, South America. Proc. 1999e. Augochlorini Beebe, 1925 (Insecta, First Intl. Palaeoentomol. Conf., Mos- Hymenoptera): Corrected authorship cow 1998: 27±32. and date (not Moure, 1943). Bull. Zool. Genise, J. F., and T. M. Bown Nomencl. 56: 198. 1996. Uruguay Roselli 1938 and Roselli- 1999f. A new xeromelissine bee in Tertiary chnus, n. ichnogenus: two ichnogenera amber of the Dominican Republic (Hy- for clusters of fossil bee cells. Ichnos menoptera: Colletidae). Entomol. Scand. 4: 199±217. 30: 453±458. [Publ. date: January 2000] Genise, J. F., and M. S. Engel 2000a. Classi®cation of the bee tribe Augo- 2000. The evolutionary history of sweat bees chlorini (Hymenoptera: Halictidae). (Hymenoptera: Halictidae): Integration Bull. Am. Mus. Nat. Hist. 250: 90 pp. of paleoentomology, paleoichnology, 166 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

and phylogeny. In V. M. de Godoi Grimaldi, D., and J. Cumming (ed.), International Meeting on Paleoar- 1999. Brachyceran Diptera in Cretaceous am- thropodology, Abstracts: 116±177. Ri- bers and Mesozoic diversi®cation of beiraÄo Preto: Universidade de SaÄo Pau- the Eremoneura. Bull. Am. Mus. Nat. lo. Hist. 239: 124 pp. Genise, J. F., and P. L. Hazeldine Grimaldi, D., E. Bonwich, M. Delannoy, and S. 1998. The ichnogenus Palmiraichnus Roselli Doberstein for fossil bee cells. Ichnos 6: 151±166. 1994. Electron microscopic studies of mum- Genise, J. F., and M. Verde mi®ed tissues in amber fossils. Am. 2000. Corimbatichnus fernandezi: A cluster Mus. Novitates 3097: 31 pp. of fossil bee cells from the Late Cre- Griswold, T. L. taceous±Early Tertiary of Uruguay. 1985. A generic and subgeneric revision of Ichnos 7: 115±125. the Heriades genus-group. Ph.D. diss., Gerlach, J. Utah State Univ., Logan, UT. 1989. Bienen-Inklusen der Gattungen Dasy- Griswold, T. L., and C. D. Michener poda, Megachile und Apis im baltisch- 1997. The classi®cation of the Osmiini of the en Bernstein. MuÈnster. Forsch. Geol. Eastern Hemisphere (Hymenoptera, PalaÈontol. 69: 251±260. Megachilidae). J. Kansas Entomol. Germar, E. F. Soc. 70: 207±253. [Publ. date: 24 1839. Die versteinerten Insecten Solenhofens. March 1988] Nova Acta Leopold. (Kaiserl. Leo- Hasiotis, S. [T.] pold.-Carol. Dtsch. Akad. Naturf.) 19: 1997. Abuzz before ¯owers. Plateau J., Mus. 187±222. North. Arizona 1: 20±27. Gess, S.K. Hasiotis, S. T., and T. M. Demko 1996. The Pollen Wasps: Ecology and Natu- 1996. Terrestrial and freshwater trace fossils, ral History of the Masarinae. Cam- Upper Jurassic Morrison Formation, bridge MA: Harvard Univ. Press. Colorado Plateau. In M. Morales (ed.), Goloboff, P. A. The continental Jurassic. Mus. North. 1993. NoName (NONA), version 1.5.1. Pro- Arizona Bull. 60: 355±370. gram and Documentation. FundacioÂn e Hasiotis, S. T., R. F. Dubiel, and T. M. Demko Instituto Miguel Lillo, TucuÂman, Ar- 1995. Triassic hymenopterous nests: Insect gentina. eusociality predates Angiosperm GoÈppert, H. R. plants. Rocky Mountain Sec., Geol. 1836. Fossile P¯anzenreste des Eisensandes Soc. Am. Reg. Meeting 27: 13. von Aachen. Nova Acta Acad. C. Le- Hasiotis, S. T., R. F. Dubiel, P. T. Kay, T. M. Dem- opold.-Carol. Germ. Nat. Cur. 19: 150 ko, K. Kowalska, and D. McDaniel pp. 1998. Research update on hymenopteran Grande, L. nests and cocoons, Upper Triassic 1985. The use of paleontology in systematics Chinle Formation, Petri®ed Forest Na- and biogeography, and a time control tional Park, Arizona. Natl. Park Serv., re®nement for historical biogeography. Paleontol. Res. [Tech. Rep. NPS/ Paleobiology 11: 234±243. NRGRD/GRDTR-98/01] 3: 116±121. Grimaldi, D. A. Heer, O. 1992. Vicariance biogeography, geographic 1849. Die Insektenfauna der TertiaÈrgebilde extinctions, and the North American von Oeningen und von Radoboj in Oligocene tsetse ¯ies. In N. J. Novacek Croatien: Zweite Abtheilung: Heus- and Q. D. Wheeler (eds.), Extinction chrecken, Flor¯iegen, Ader¯uÈgler, and Phylogeny: 178±204. New York: Schmetterlinge und Fliegen. Neue Columbia Univ. Press. Denkschr. Allg. Schweiz. Gesell. Ges. 1995. The age of Dominican amber. In K. B. Natwiss. 11: 1±264. Anderson and J. C. Crelling (eds.), 1865. Die Urwelt der Schweiz. ZuÈrich: Fried- Amber, resinite, and fossil resins: 203± rich Schulthess. 217. Washington DC: Am. Chem. Soc. 1867. Fossile Hymenopteren aus Oeningen 1999. The co-radiations of insects and angio- und Radoboj. Neue Denkschr. Allg. sperms in the Cretaceous. Ann. Mis- Schweiz. Gesell. Ges. Natwiss. 22: 1± souri Bot. Gard. 86: 373±406. 42. 2001 ENGEL: BALTIC AMBER BEES 167

Hong, Y.-C. ography. Bull. Am. Mus. Nat. Hist. 1983. Fossil insects in the diatoms of Shan- 238: 95 pp. wang. Bull. Tianjin Inst. Geol. Miner. Jurine, L. Res. 8: 1±11. [In Chinese, with English 1807. Nouvelle MeÂthode de Classer les Hy- summary] meÂnopteÁres et les DipteÁres, vol. 1. Ge- 1984. New fossil insects of Laiyang Group neÂve [Geneva]: Paschoud. from Laiyang Basin, Shandong Prov- Kay, P. T., J. King, S. T. Hasiotis ince. Prof. Pap. Stratigr. Paleontol. 11: 1999. Petri®ed Forest National Park Upper 31±41. [In Chinese, with English sum- Triassic trace fossils yield biochemical mary] evidence of phylogenetic link to mod- 1985. Fossil Insects, Scorpionids and Ara- ern bees (Hymenoptera, Apoidea). neids in the Diatoms of Shanwang. Bei- Proc. First Intl. Palaeoentomol. Conf., jing: Geological Publishing House. [In Moscow 1998: 60. Chinese, with English summary] Keilbach, R. Hong, Y.-C., and S.-J. Miao 1982. Bibliographie und Liste der Arten tier- 1992. Fossil bee [sic] and its origin with dis- ischer EinschluÈsse in fossilen Harzen cussion on the origin of the angiosperm sowie ihrer Aufbewahrungsorte. Dtsch. [sic]. Mem. Beijing Nat. Hist. Mus. 51: Entomol. Z. 29: 129±286. 1±19. [In Chinese, with English sum- Kelner-Pillault, S. mary] 1969a. Abeilles fossiles ancetres des apides so- Hope, F. W. ciaux. Proc. VI Congr. IUSSI, Bern 1836. Observations on succinic insects. Trans. Entomol. Soc. London 1: 133± 1969: 85±93. [Publ. date: 15 September 147. 1969] Illiger, K. 1969b. Les abeilles fossiles. Dalle Mem. Soc. 1806. William Kirby's Familien der Bienen- Entomol. Ital. 48: 519±534. [Publ. date: artigen Insekten mit Zusatzen, Na- 30 December 1969] chweisungen und Bemerkungen. Mag. 1970a. L'ambre Balte et sa faune entomolo- Insektenkd. 5: 28±175. gique avec description de deux apoides International Commission on Zoological Nomen- nouveaux. Ann. Soc. Entomol. France clature 6: 3±24. 1993. Some bee family-group names (Insecta, 1970b. Une meÂlipone (s.l.) de l'ambre Balte Hymenoptera): Names based on Col- (Hym. Apidae). Ann. Soc. Entomol. letes Latreille, 1802, on Paracolletes France 6: 437±441. Smith, 1853, on Halictus Latreille, 1974. EÂ tat d'eÂvolution des apides de l'ambre 1804, on Anthidium Fabricius, 1804 Balte. Ann. Soc. Entomol. France: and on Anthophora Latreille, 1803 giv- 623±634. en precedence over some senior names. Kerr, W. E., and R. A. da Cunha Bull. Zool. Nomencl. 50: 85±89. 1976. Taxonomic position of two fossil social 1999a. Dasypodidae BoÈrner, 1919 (Insecta, bees (Apidae). Rev. Biol. Trop. 24: 35± Hymenoptera): Spelling emended to 43. Dasypodaidae, so removing the hom- Kerr, W. E., and V. Maule onymy with Dasypodidae Gray, 1821 1964. Geographic distribution of stingless (Mammalia, Xenarthra). Bull. Zool. bees and its implications (Hymenop- Nomencl. 56: 156±157. tera: Apidae). J. New York Entomol. 1999b. International Code of Zoological No- Soc. 72: 2±17. menclature. London: International Trust Kirby, W. for Zoological Nomenclature. [Fourth 1802. Monographia Apum Angliae, or, An edition] Attempt to Divide into their Natural 2000. Apis proava Menge, 1856 (currently Genera and Families, such Species of Electrapis proava; Insecta, Hymenop- tera): Conserved by the designation of the Linnean Genus Apis, as have been a neotype. Bull. Zool. Nomencl. 57: Discovered in England. [2 vols.] Ips- 236. wich: White. Itturalde-Vinent, M. A., and R. D. E. MacPhee 1837. Part IV, Insects. In J. Richardson, Fau- 1996. Age and paleogeographical origin of na Boreali-Americana; or the Zoology Dominican amber. Science 273: 1850± of the Northern Parts of British Amer- 1852. ica; Containing Descriptions of the Ob- 1999. Paleogeography of the Caribbean re- jects of Natural History Collected on gion: Implications for Cenozoic bioge- the Late Northern Land Expeditions, 168 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Under Command of Captain Sir John relle, AppliqueÂe aux Arts, Principale- Franklin, R.N.: 1±325. London: Long- ment aÁ l'Agriculture et aÁ l'Economie man. Rurale et Domestique, Tome 24, Char- Kirby, W., and W. Spence acteÁres et Tables: 129±200. Paris: De- 1826. An Introduction to Entomology, vol. 3. terville. London: Longman. 1809. Genera Crustaceorum et Insectorum Kohring, R., and T. SchluÈter Secundum Ordinem Naturalem in Fam- Historische und palaÈontologische Bes- 1989. ilias Disposita, Iconibus Exemplisque tandsaufnahme des Simetits, eines fos- Plurimis Explicata, Tome 4. Paris: Ko- silen Harzes mutmaÈûlich mio/pliozaÈnen Alters aus Sizilien. Doc. Nat. 56: 33± enig. 58. Lepeletier de Saint Fargeau, A. L. M. Kosmowska-Ceranowicz, B. 1836. Histoire Naturelle des InsectesÐHy- 1987. Charakterystyka mineralogiczno-petro- meÂnopteÁres, Tome 1. Paris: Roret. gra®czna bursztynonosÂnych osadoÂw Lidgard, S., and P. R. Crane Eocenu w okolicach Chøapowo oraz os- 1988. Quantitative analyses of the early an- adoÂw Paleogenu Poønocnej Polski. giosperm radiation. Nature 331: 344± Biul. Inst. Geol. 356: 29±50. 346. Kosmowska-Ceranowicz, B., and C. MuÈller Linnaeus, C. [LinneÂ, K., von] 1985. Lithology and calcareous nannoplank- 1758. Systema Naturae per Regna Tria Na- ton in amberbearing Tertiary sediments turae, Secundum Classes, Ordines, from boreholes Chøapowo (Northern Genera, Species, cum Characteribus, Poland). Bull. Pol. Acad. Sci. 33: 119± Differentiis, Synonymis, Locis, vol. 1, 128. ed. 10, Reformata. Holmiae [Stock- Koulianos, S., R. Schmid-Hempel, D. W. Roubik, holm]: Salviae. and P. Schmid-Hempel Lockley, M. G., and M. Matsukawa 1999. Phylogenetic relationships within the 1999. corbiculate Apinae (Hymenoptera) and Some observations on trackway evi- the evolution of eusociality. J. Evol. dence for gregarious behavior among Biol. 12: 380±384. small bipedal dinosaurs. Palaeogeogr., Lambert, J. B., J. S. Frye, and G. O. Poinar, Jr. Palaeoclimatol., Palaeoecol. 150: 25± 1985. Amber from the Dominican Republic: 31. Analysis by nuclear magnetic reso- Lomholdt, O. nance spectroscopy. Archaeometry 27: 1982. On the origin of the bees (Hymenop- 43±51. tera: Apidae, Sphecidae). Entomol. Langenheim, J. H. Scand. 13: 185±190. 1969. Amber: A botanical inquiry. Science LourencËo, W. R., and W. Weitschat 163: 1157±1169. 1996. More than 120 years after its descrip- Lanham, U. N. tion, the enigmatic status of the genus 1979. Possible phylogenetic signi®cance of of the Baltic amber scorpion Tityus complex hairs in bees and ants. J. New eogenus Menge, 1869 can ®nally be York Entomol. Soc. 87: 91±94. 1980. Evolutionary origin of bees (Hymenop- clari®ed. Mitt. Geol.±PalaÈontol. Inst. tera: Apoidea). J. New York Entomol. Univ. Hambg. 79: 183±193. Soc. 88: 199±209. Lutz, H. Larsson, S. G. 1993. Eckfeldapis electrapoides nov. gen. n. 1978. Baltic AmberÐA Paleobiological sp., eine ``Honigbiene'' aus dem Mit- Study. Klampenborg: Scandinavian tel-EozaÈn des ``Eckfelder Maares'' bei Science Press. Manderscheid/Eifel, Deutschland (Hy- Latreille, P. A. menoptera: Apidae, Apinae). Mainzer 1802a. Histoire Naturelle des Fourmis, et Re- Natwiss. Arch. 31: 177±199. cueil de MeÂmoires et d'Observations Malyshev, S. I. sur les Abeilles, les AraigneÂes, les Fau- 1968. Genesis of the Hymenoptera and the cheurs, et Autres Insectes. Paris: Cra- Phases of their Evolution. London: Me- pelet. 1802b. Histoire Naturelle GeÂneÂrale et Particu- thuen. lieÁre des CrustaceÂs et des Insectes, Manning, F. J. Tome 3. Paris: Dufart. 1960. A new fossil bee from Baltic amber. 1804. Tableau meÂthodique des insectes. In Verh. XI Intl. Kongr. Entomol., Wien Nouveau Dictionnaire d'Histoire Natu- 1: 306±308. [Publ. date: 1961] 2001 ENGEL: BALTIC AMBER BEES 169

Mardulyn, P., and S. A. Cameron ganomiinae. Contrib. Am. Entomol. 1999. The major opsin in bees (Insecta: Hy- Inst. 18: 1±135. menoptera): A promising nuclear gene 1982. A new interpretation of fossil social for higher level phylogenetics. Mol. bees from the Dominican Republic. So- Phylogenet. Evol. 12: 168±176. ciobiol. 7: 37±45. McGinley, R. J. 1983. The classi®cation of the Lithurginae 1981. Systematics of the Colletidae based on (Hymenoptera: Megachilidae). Pan- mature larvae with phenetic analysis of Pac. Entomol. 59: 176±187. apoid larvae (Hymenoptera: Apoidea). 1986. Family-group names among bees. J. Univ. California Publ. Entomol. 91: 1± Kansas Entomol. Soc. 59: 219±234. 307. 1990. Classi®cation of the Apidae (Hyme- McKenna, M. C. noptera). Univ. Kansas Sci. Bull. 54: 1975. Fossil mammals and early Eocene 75±164. North Atlantic land continuity. Ann. 1991. Proposed precedence of some bee fam- Missouri Bot. Gard. 62: 335±353. ily-group names (Insecta, Hymenop- McKenna, M. C., and S. K. Bell tera): Names based on Colletes Latreil- 1997. Classi®cation of Mammals Above the le, 1802, on Paracolletes Smith, 1853, Species Level. New York: Columbia on Halictus Latreille, 1804, on Anthi- Univ. Press. dium Fabricius, 1804 and on Anthopho- Melo, G. A. R. ra Latreille, 1803 to have precedence 1999. Phylogenetic relationships and classi®- over some senior names. Bull. Zool. cation of the major lineages of Apoidea Nomencl. 48: 227±235. (Hymenoptera), with emphasis on the 1997. Genus-group names of bees and sup- crabronid wasps. Univ. Kansas Nat. plemental family-group names. Univ. Hist. Mus. Sci. Pap. 14: 1±55. Kansas Nat. Hist. Mus. Sci. Pap. 1: 1± Menge, A. 81. 1856. Lebenszeichen vorweltlicher, im Bern- 1999. The corbiculae of bees. Apidologie 30: stein eingeschlossener Thiere. Danzig: 67±74. Kafemann. 2000a. The Bees of the World. Baltimore MD: Michener, C. D. Johns Hopkins Univ. Press. 1941. A generic revision of the American Os- 2000b. What was the proto-bee? In M.M.G. miini with descriptive notes on Old Bitondi and K. Hartfelder (eds.), Anais World genera. Am. Midl. Nat. 26: 147± do IV Encontro Sobre Abelhas: 2±8. 166. RibeiraÄo Preto: Universidade de SaÄo 1944. Comparative external morphology, Paulo. phylogeny, and a classi®cation of the Michener, C. D., and R. W. Brooks bees (Hymenoptera). Bull. Am. Mus. 1984. Comparative study of the glossae of Nat. Hist. 82: 151±326. bees (Apoidea). Contrib. Am. Entomol. 1965. A classi®cation of the bees of the Aus- Inst. 22: 1±73. tralian and South Paci®c regions. Bull. Michener, C. D., and A. Fraser Am. Mus. Nat. Hist. 130: 1±362. 1978. A comparative anatomical study of mandibular structure in bees. Univ. 1977. Discordant evolution and the classi®- Kansas Sci. Bull. 51: 463±482. cation of allodapine bees. Syst. Zool. Michener, C. D., and L. Greenberg 26: 32±56. 1980. Ctenoplectridae and the origin of long- 1978. The classi®cation of halictine bees: tongued bees. Zool. J. Linn. Soc. 69: Tribes and Old World nonparasitic gen- 183±203. era with strong venation. Univ. Kansas Michener, C. D., and D. A. Grimaldi Sci. Bull. 51: 501±538. 1988a. A Trigona from Late Cretaceous amber 1979. Biogeography of the bees. Ann. Mis- of New Jersey (Hymenoptera: Apidae: souri Bot. Gard. 66: 277±347. Meliponinae). Am. Mus. Novitates 1981a. Comparative morphology of the middle 2917: 10 pp. coxae of Apoidea. J. Kansas Entomol. 1988b. The oldest fossil bee: Apoid history, Soc. 54: 319±326. evolutionary stasis, and antiquity of so- 1981b. Classi®cation of the bee family Melit- cial behavior. Proc. Natl. Acad. Sci., tidae with a review of species of Me- U.S.A. 85: 6424±6426. 170 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Michener, C. D., and T. L. Griswold Nascimbene, P., and H. Silverstein 1994. The classi®cation of Old World Anthi- 2000. The preparation of fragile Cretaceous diini (Hymenoptera, Megachilidae). ambers for conservation and study of Univ. Kansas Sci. Bull. 55: 299±327. organismal inclusions. In D. Grimaldi Michener, C. D., and R. B. Lange (ed.), Studies on Fossils in Amber, with 1958. Observations on the behavior of Bras- Particular Reference to the Cretaceous ilian halictid bees, III. Univ. Kansas of New Jersey: 93±102. Leiden: Back- Sci. Bull. 39: 473±505. huys. Michener, C. D., and G. O. Poinar, Jr. Newman, E. 1996. The known bee fauna of the Dominican 1834. Attempted division of British insects amber. J. Kansas Entomol. Soc., Suppl. into natural orders. Entomol. Mag. 2: 69: 353±361. [Publ. date: 15 January 379±431. 1997] Nixon, K. C. Michener, C. D., and J. G. Rozen, Jr. 1999. WINCLADA, version 0.9.99tuc.13, 1999. A new ground-nesting genus of xero- beta. Program and Documentation, melissine bees from Argentina and the Cornell Univ., Ithaca, NY. tribal classi®cation of the subfamily Nixon, K. C., and J. M. Carpenter (Hymenoptera: Colletidae). Am. Mus. 1996. On consensus, collapsibility, and clade Novitates 3281: 10 pp. concordance. Cladistics 12: 305±321. Minckley, R. L. Noll, F. B. 1998. A cladistic analysis and classi®cation 1998. Are behavioral characters informative of the subgenera and genera of the of phylogenetic relationships among large carpenter bees, tribe Xylocopini the corbiculate bees (Hymenoptera, (Hymenoptera: Apidae). Univ. Kansas Apidae, Apinae). Proc. 13th Intl. Congr. Nat. Hist. Mus. Sci. Pap. 9: 1±47. IUSSI, Adelaide 1998: 347. Moldenke, A. R. Norell, M. A., and M. J. Novacek 1976. California pollination ecology and veg- 1992a. etation types. Phytologia 34: 305±361. The fossil record and evolution: Com- Motschulsky, V., de paring cladistic and paleontologic evi- 1856. Voyages. Lettres de M. de Motschulsky dence for vertebrate history. Science aÁM.MeÂneÂtrieÂs. Etude Entomol. 5: 3± 255: 1690±1693. 38. 1992b. Congruence between superpositional Moure, J. S. and phylogenetic patterns: Comparing 1946. MelõÂponas do Brasil. ChaÂcaras Quint. cladistic patterns with fossil records. (SaÄo Paulo) 74: 609±612. Cladistics 8: 319±337. 1949. Las especies chilenas de la sub-familia Norell, M. A., J. M. Clark, L. M. Chiappe, and Lithurginae (Hym.ÐApoidea). Arq. D. Dashzeveg Mus. Parana. 7: 265±286. 1995. A nesting dinosaur. Nature 378: 774± 1961. A preliminary supra-speci®c classi®- 776. cation of the Old World meliponine Novacek, M. J., and Q. D. Wheeler bees (Hym., Apoidea). Stud. Entomol. 1992. Extinction and Phylogeny. New York: 4: 181±242. Columbia Univ. Press. Moure, J. S., and J. M. F. Camargo Novak, O. 1978. A fossil stingless bee from copal (Hy- 1877. Fauna der Cyprisschiefer des Egerer menoptera: Apidae). J. Kansas Ento- TertiaÈrbeckens. Sitzungsber. Akad. mol. Soc. 51: 560±566. [Publ. date: 17 Wiss. Wien, Math.-Natwiss. Kl. 76: November 1978] 71±96. Moure, J. S., and C. D. Michener Olfers, E., von 1955. The bee family Fideliidae in South 1907. Die ``Ur-Insekten'' (Thysanura und America (Hymenopt.ÐApoidea). Du- Collembola) im Bernstein. Schr. Phys.- senia 6: 199±206. OÈ kon. Gesell. 48: 1±40. MuÈller, H. Ornduff, R. 1872. Anwendung der Darwinschen Lehre 1991. Size classes, reproductive behavior, and auf Bienen. Verh. Naturhist. Ver. insect associates of Cycas media (Cy- Preuss. Rheinlande Westphalen 29: 1± cadaceae) in Australia. Bot. Gaz. 152: 96. 203±207. 2001 ENGEL: BALTIC AMBER BEES 171

Panzer, G. W. F. pretation of past behavior based on 1806. Kritische Revision der Insektenfauna functional morphology. Entomol. Deutschlands, vol. 2. NuÈrnberg: Fels- Scand. 22: 193±199. secker. 1994. Bees in fossilized resin. Bee World 75: 1809. Faunae Insectorum Germanicae Initia 71±77. oder Deutschlands Insecten, Heft 107. 1998. Paleoeuglossa melissi¯ora gen. n., sp. NuÈrnberg: Felssecker. n. (Euglossinae: Apidae), fossil orchid Patiny, S. bees in Dominican amber. J. Kansas 1999. Etude phylogeÂneÂtique des Panurginae Entomol. Soc. 71: 29±34. [Publ. date: de l'ancien monde (Hymenoptera, An- 9 February 1999] drenidae). Linzer Biol. Beitr. 31: 249± Poinar, G. O., Jr., and J. Haverkamp 275. 1985. Use of pyrolysis mass spectroscopy in Paton, D. C. the identi®cation of amber samples. J. 1993. Honeybees in the Australian environ- Baltic Stud. 16: 210±221. ment. Bioscience 43: 95±103. Prentice, M. Patterson, C. 1991. Morphological analysis of the tribes of 1981. Signi®cance of fossils in determining Apidae. In D. R. Smith (ed.), Diversity evolutionary relationships. Annu. Rev. in the genus Apis: 51±69. Boulder CO: Ecol. Syst. 12: 195±223. Westview Press. Pesenko, Yu. A. Proctor, M., P. Yeo, and A. Lack 1983. Fauna of the U.S.S.R., Hymenopteran 1996. The natural History of Pollination. Insects, Vol. 17, Nr. 1, Halictid Bees Portland OR: Timber Press. (Halictidae), Subfamily Halictinae, Prothero, D. R. Tribe Nomioidini (in the Palaearctic 1994. The Eocene-Oligocene Transition: Par- Fauna). Leningrad [St. Petersburg]: adise Lost. New York: Columbia Univ. Zool. Inst., Acad. Sci. [In Russian] Press. 1999. Phylogeny and classi®cation of the Radchenko, V. G., and Yu. A. Pesenko family Halictidae revised (Hymenop- 1994a. ``Protobee'' and its nests: A new hy- tera: Apoidea). J. Kansas Entomol. Soc. pothesis concerning the early evolution 72: 104±123. [Publ. date: 19 January of Apoidea (Hymenoptera). Entomol. 2000] Obozr. 73: 913±933. [In Russian] Pesenko, Yu. A., J. Banaszek, V. G. Radchenko, 1994b. Biology of Bees (Hymenoptera: Apo- and T. Cierzniak idea). St. Petersburg: Russian Academy 2000. Bees of the Family Halictidae (Exclud- of Sciences. ing Sphecodes) of Poland: Taxonomy, 1996. ``Protobee'' and its nests: A new hy- Ecology, Bionomics. Bydgoszcz: Ped- pothesis concerning the early evolution agogical Univ. of Apoidea (Hymenoptera). Entomol. Petanidou, T., and D. Vokou Rev. 75: 140±162. [Translation of Rad- 1990. Pollination and pollen energetics in chenko and Pesenko, 1994a] Mediterranean ecosystems. Am. J. Bot. Rasnitsyn, A. P. 77: 986±992. 1975. HymenopteraÐApocrita of the Meso- Petrov, P. zoic. Tr. Paleontol. Inst. Akad. Nauk 1992. Distribution and phylogenesis of the SSSR 147: 1±132. [In Russian] bee genus Apis (Hymenoptera, Api- 1988. An outline of evolution of the hyme- dae). Usp. Sovrem. Biol., Moscow 112: nopterous insects (order Vespida). Ori- 359±372. [In Russian] ent. Insects 22: 115±145. Pielinska, A. Rasnitsyn, A. P., and C. D. Michener 1997. Inclusions of wood in the amber col- 1991. Miocene fossil bumble bee from the lections of the Museum of the Earth in Soviet Far East with comments on the Warsaw. Metalla, Bochum 66: 25±28. chronology and distribution of fossil Piton, L.-E. bees (Hymenoptera: Apidae). Ann. En- 1940. PaleÂontologie du Gisement EÂ oceÁne de tomol. Soc. Am. 84: 583±589. Menat (Puy-de-DoÃme) (Flore et Fau- Rasnitsyn, A. P., E. A. Jarzembowski, and A. J. ne). Paris: Lechevalier. Ross Poinar, G. O., Jr. 1998. Wasps (Insecta: Vespida ϭ Hymenop- 1991. Praecoris dominicana gen. n., sp. n. tera) from the Purbeck and Wealden (Hemiptera: Reduviidae: Holoptilinae) (Lower Cretaceous) of southern Eng- from Dominican amber, with an inter- land and their biostratigraphical and pa- 172 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

laeoenvironmental signi®cance. Cretac. Roubik, D. W. Res. 19: 329±391. 1983. Nest and colony characteristics of Raven, P. H., and D. I. Axelrod stingless bees from PanamaÂ. J. Kansas 1974. Angiosperm biogeography and past Entomol. Soc. 56: 327±355. continental movements. Ann. Missouri Roubik, D. W., J. E. Moreno, C. Vergara, and D. Bot. Gard. 61: 539±673. Wittmann Reyes, S. G. 1986. Sporadic food competition with the Af- 1998. A cladistic analysis of the bee tribe Al- rican honey bee: Projected impact on lodapini (Hymenoptera: Apidae: Xylo- neotropical social bees. J. Trop. Ecol. copinae). Philipp. Entomol. 12: 55±84. 2: 97±111. Riou, B. Roussy, L. 1999. Descriptions de quelques insectes fos- 1937. Contributions a l'etude de l'abeille Ter- siles du MioceÁne supeÂrieur de la Mon- tiaire, de ses parasites et de ses ennem- tagne d'Andance. EPHE Biol. Evol. In- is. Gaz. Apic., Montfavet 388: 49±72. sectes 11/ 12: 123±133. 1960. Insectes et abeilles fossils de l'ambre Ritzkowski, S. de Sicile: Migrations, localisations, 1997. K-Ar-Altersbestimmungen der bern- peuplement du Nouveau Monde, de steinfuÈhrenden Sedimente des Sam- l'Australie, de la Nouvelle Zelande. landes (PalaÈogen, Bezirk Kaliningrad). Gaz. Apic., Montfavet 635: 5±8. Metalla, Bochum 66: 19±23. Rozen, J. G., Jr. Robertson, C. 1970. Biology, immature stages, and phylogenetic relationships of ®deliine bees, 1903. Synopsis of Megachilidae and Bombi- with the description of a new species nae. Trans. Am. Entomol. Soc. 29: of Neo®delia (Hymenoptera, Apoidea). 163±178. Am. Mus. Novitates 2427: 25 pp. 1904. Synopsis of Anthophila. Can. Entomol. 1973. Life history and immature stages of the 36: 37±43. bee Neo®delia (Hymenoptera, Fideli- Roig-Alsina, A., and C. D. Michener idae). Am. Mus. Novitates 2519: 14 pp. 1993. Studies of the phylogeny and classi®- 1996. A new species of the bee Heterosarus cation of long-tongued bees (Hyme- from Dominican amber (Hymenoptera: noptera: Apoidea). Univ. Kansas Sci. Andrenidae; Panurginae). J. Kansas Bull. 55: 123±162. Entomol. Soc., Suppl. 69: 346±352. Ronquist, F., A. P. Rasnitsyn, A. Roy, K. Eriksson, [Publ. date: 15 January 1997] and M. Lindgren 1997. South American rophitine bees (Hy- 1999. Phylogeny of the Hymenoptera: A cla- menoptera: Halictidae: Rophitinae). distic reanalysis of Rasnitsyn's (1988) Am. Mus. Novitates 3206: 27 pp. data. Zool. Scr. 28: 13±50. Sakagami, S. F. RoÈschmann, F., and W. Mohrig 1959. Some interspeci®c relations between 1995. Die TrauermuÈcken des SaÈchsischen Japanese and European honeybees. J. Bernsteins aus dem UntermiozaÈn von Anim. Ecol. 28: 51±68. Bitterfeld/Deutschland (Diptera, Sciar- 1974. Sozialstruktur und Polymorphismus bei idae). Dtsch. Entomol. Z. 42: 17±54. Furchen- und Schmalbienen. In G. H. Roselli, F. L. Schmidt (ed.), Sozialpolymorphismus 1938. Apuntes de geologõÂa y paleontologõÂa bei Insekten: 257±293. Stuttgart: Wis- uruguaya. Sobre insectos del CretaÂcico senschaftliche Verlagsgesellschaft MBH. del Uruguay o descubrimiento de ad- 1976. Speci®c differences in the bionomic mirables instintos constructivos de esa characters of bumblebees. A compara- eÂpoca. Bol. Soc. Amig. Cienc. Nat. tive review. J. Fac. Sci., Hokkaido ``Kraglievich-Fontana'' 1: 72±102. Univ., ser. 6 (Zool.) 20: 390±447. Ross, A. J. 1978. Tetragonula stingless bees of the con- 1998. Amber: The Natural Time Capsule. tinental Asia and Sri Lanka (Hymenop- London: The Natural History Museum. tera, Apidae). J. Fac. Sci., Hokkaido Ross, A. J., and P. V. York Univ., ser. 6 (Zool.) 21: 165±247. 2000. A list of type and ®gured specimens of [Publ. date: June 1978] insects and other inclusions in Burmese Sakagami, S. F., and C. D. Michener amber. Bull. Nat. Hist. Mus., London 1962. The Nest Architecture of the Sweat (Geol.) 56: 11±20. Bees (Halictinae): A Comparative 2001 ENGEL: BALTIC AMBER BEES 173

Study of Behavior. Lawrence KS: Univ. Simmons, N. B., and J. H. Geisler Kansas Press. 1998. Phylogenetic relationships of Icaron- 1987. Tribes of Xylocopinae and origin of the ycteris, Archaeonycteris, Hassianycter- Apidae (Hymenoptera: Apoidea). Ann. is, and Palaeochiropteryx to extant bat Entomol. Soc. Am. 80: 439±450. lineages, with comments on the evolu- Salt, G. tion of echolocation and foraging strat- 1931. Three bees from Baltic amber. Bern- egies in Microchiroptera. Bull. Am. stein-Forsch. 2: 136±147. Mus. Nat. Hist. 235: 182 pp. Sandhouse, G. A. Smith, F. 1943. The type species of the genera and sub- 1853. Catalogue of Hymenopterous Insects in genera of bees. Proc. U.S. Natl. Mus. the Collection of the British Museum, 92: 519±619. Part 1: Andrenidae and Apidae. Lon- Saussure, H., de don: British Museum. 1890. Histoire naturelle des HymeÂnopteÁres. In Snodgrass, R. E. A. Grandidier (ed.), Histoire Physique, 1935. Principles of Insect Morphology. New Naturelle et Politique de Madagascar, York: McGraw Hill. tome 20: 1±590. Paris: Imprimerie Na- 1941. The male genitalia of Hymenoptera. tionale. Smithson. Misc. Coll. 99: 1±86. Schenck, A. 1956. Anatomy of the Honey Bee. Ithaca NY: 1860. Verzeichniss der nassauischen Hyme- Cornell Univ. Press. noptera aculeata. Stettiner Entomol. Spicer, R. A., P. McArees, and J. L. Chapman Ztg. 21: 132±157, 417±419. 1993. Cretaceous phytogeography and cli- 1861. Die Nassauischen Bienen. Jahrb. Ver. mate signals. Philos. Trans. R. Soc. Naturkd. Herzogthum Nassau 14: 1± London, ser. B, Biol. Sci. 341: 277± 414. 286. 1869. Beschreibung der nassauischen Bienen, Spinola, M. zweiter Nachtrag. Jahrb. Nassau. Ver. 1808. Insectorum Liguriae Species Novae aut Naturkd. 21: 269±382. [Preprint, dated Rariores, Quas in Agro Ligustico nuper 1868, publ. 1869; refer to Michener Detexit, Descripsit, et Iconibus Illus- (1986) for details of dating.] travit Maximilianus Spinola, adjecto Schultz, T. R., M. S. Engel, and M. Prentice Catalogo Spiecierum Auctoribus jam 1999. Resolving con¯ict between morpholog- Enumeratarum, Quae in Eadam Re- ical and molecular evidence for the or- gione Occurrunt, vol. 2. Genuae: Gra- igin of eusociality in the ``corbiculate'' vier. bees (Hymenoptera: Apidae): A hy- Statz, G. pothesis-testing approach. Univ. Kan- 1936. Ueber alte und neue fossile Hymenop- sas Nat. Hist. Mus. Spec. Publ. 24: terenfunde aus den tertiaÈren Ablagerun- 125±138. gen von Rott am Siebengebirge. De- Schumann, H., and H. Wendt cheniana, Bonn 93: 256±312. 1989. Kenntnis der tierischen Inklusen des Stuckenberg, R. R. SaÈchsischen Bernsteins. Dtsch. Ento- 1975. New fossil species of Phlebotomus and mol. Z. 36: 33±44. Haematopota in Baltic amber (Diptera: Shedrinsky, A. M., D. Grimaldi, T. P. Wampler, Psychodidae, Tabanidae). Ann. Natal and N. S. Baer Mus. 22: 455±464. 1991. Amber and copal: Pyrolysis gas chro- Sugden, E. A., R. W. Thorp, and S. L. Buchmann matographic (PyGC) studies of prove- 1996. Honey bee-native bee competition in nance. Wiener Ber. Natwiss. Kunst 6± Australia: Focal point for environmen- 8: 37±63. tal change and apicultural response. Shuckard, W. E. Bee World 77: 26±44. 1866. British Bees: An Introduction to the Sun, G., D. L. Dilcher, S. Zheng, and Z. Zhou Study of the Natural History and Econ- 1998. In search of the ®rst ¯ower: A Jurassic omy of the Bees Indigenous to the Brit- angiosperm, Archaefructus, from north- ish Isles. London: Reeve and Co. east China. Science 282: 1692±1695. Silvestri, F. Taylor, D. W., and L. J. Hickey 1912. Die Thysanura des baltischen Bern- 1992. Phylogenetic evidence for the herba- steins. Schr. Phys.-OÈ kon. Gesell. 53: ceous origin of angiosperms. Plant 42±66. Syst. Evol. 180: 137±156. 174 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Terzo, M. In W. L. Halverson and G. J. Maender 1999. ReÂvision du genre Exoneuridia Cock- (eds.), Fourth California Islands Sym- erell, 1911 (Hymenoptera Apoidea Xy- posium: Update on the Status of Re- locopinae Allodapini). Belg. J. Ento- sources: 351±365. Santa Barbara CA: mol. 1: 137±152. Santa Barbara Mus. Nat. Hist. Thomson, C. G. Wheeler, W. M. 1869. Opuscula Entomologica, Fasc. 1. Lund: 1914. The ants of the Baltic amber. Schr. Lundbergska. Phys.-OÈ kon. Gesell. 55: 1±142. Thorp, R. W. Wilford, J. N. 1979. Structural, behavioral, and physiologi- 1995. Which came ®rst: bees or ¯owers? Find cal adaptations of bees (Apoidea) for points to bees. New York Times, May collecting pollen. Ann. Missouri Bot. 23: C1, C11. Gard. 66: 788±812. Wille, A. TkalcuÊ, B. 1959. A new stingless bee (Meliponini) from 1966. Megabombus (Fervidobombus) abditus the amber of Chiapas, Mexico. J. Pa- sp. n. aus aÈquatorial-Afrika. Cas. Mo- leontol. 33: 849±852. rav. Mus. Brne 51: 271±274. 1977. A general review of the fossil stingless Tosi, A. bees. Rev. Biol. Trop. 25: 43±46. 1896. Di un nuovo genre di Apiaria fossile Wille, A., and L. C. Chandler nell'ambra di Sicilia (Meliponorytes 1964. A new stingless bee from the Tertiary succiniÐM. sicula). Riv. Ital. Paleon- amber of the Dominican Republic (Hy- tol., Bologna 2: 352±356. menoptera; Meliponini). Rev. Biol. Turkin, N. I. Trop. 12: 187±195. 1997. Preliminary results of microscopic re- Williams, P. H. search of tangential wood imprints in 1998. An annotated checklist of bumble bees Baltic amber. Metalla, Bochum 66: 55± with an analysis of patterns of descrip- 56. tion (Hymenoptera: Apidae, Bombini). Unger, F. Bull. Br. Mus. Nat. Hist. (Entomol.) 67: 1867. Die fossile Flora von Kumi auf der In- 79±152. sel Euboea. Denkschr. Kaiserl. Akad. Winston, M. L., and C. D. Michener Wiss., Math.-Natwiss. Cl. 27: 27±200. 1977. Dual origin of highly social behavior Urban, D. among bees. Proc. Natl. Acad. Sci., 1967. As espeÂcies do geÃnero Thygater Holm- U.S.A. 74: 1135±1137. berg, 1884 (Hymenoptera, Apoidea). Zeuner, F. E. Bol. Univ. Fed. ParanaÂ, Zool. II, 12: 1931. Die Insektenfauna des BoÈttinger Mar- 177±309. Weber, W. A. mors. Fortschr. Geol. Palaeontol. 9: 1965. Theodore Dru Alison Cockerell, 1866± 247±406. 1948. Univ. Colorado Stud., Ser. Bib- 1938. Die Insektenfauna des Mainzer Hydro- liogr. 1: 1±124. bienkalks. Palaeontol. Z. 20: 104±159. 2000. The American Cockerell: A Naturalist's Zeuner, F. E., and F. J. Manning Life, 1866±1948. Boulder: Univ. Press 1976. A monograph on fossil bees (Hyme- of Colorado. noptera: Apoidea). Bull. Br. Mus. Nat. Weitschat, W. Hist. (Geol.) 27: 149±268. 1997. Bitterfelder BernsteinÐEin eozaÈner Zhang, J.-F. Bernstein auf miozaÈner LagerstaÈtte. 1990. New fossil species of Apoidea (Insecta: Metalla, Bochum 66: 71±84. Hymenoptera). Acta Zootaxon. Sinica Weitschat, W., and W. Wichard 15: 83±91. [In Chinese, with English 1998. Atlas der P¯anzen und Tiere im Bal- summary] tischen Bernstein. MuÈnchen [Munich]: Zhang, J.-F., B. Sun, and X.-Y. Zhang Verlag Friedrich Pfeil. 1994. Miocene Insects and Spiders from Wenner, A. M., and R. W. Thorp Shanwang, Shandong. Beijing: Science 1994. Removal of feral honey bee (Apis mel- Press. [In Chinese, with English sum- lifera) colonies from Santa Cruz Island. mary] 2001 ENGEL: BALTIC AMBER BEES 175

APPENDIX 1 Bees in Amber and Copal The following list enumerates those valid species presently recognized as inclusions in both amber and copal (synonymous names are not listed). The list excludes incertae sedis taxa. All species known from amber are extinct while only one of those recognized from copal is considered an extinct species (Liotrigona vetula). The two meliponine species listed as in Sicilian amber (Tosi, 1896) may actually be in East African copal and synonymous with Recent stingless bee species. Unfortunately, Tosi's specimens were destroyed by a bomb during World War II and their true identity will, therefore, forever remain a mystery. Apis catanensis, also from Sicilian ``amber'', is listed, As discussed by Engel (1999c), A. catanensis is a nomen dubium and was perhaps not a bee at all (as suspected by Kohring and SchluÈter, 1989); or, it may have been a living bee (A. mellifera) in African copal. Owing to the uncertainty over their identities, I have retained all of the Sicilian specimens in the list as bees occurring in true amber. The Eocene amber of Arkansas is rich in insert inclusions. It will be interesting to see if bees are ever discovered from these deposits. Owing to the relative contemporaneous age with the Baltic amber fauna, the possibility of discovering similar taxa is tantalizing. An annotated, general catalog of the world's species of fossil bees (both amber inclusions and compression fossils) as well as trace fossils attributed to bees will be presented elsewhere (Engel, in prep.) 176 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

APPENDIX 1Ð(Continued ) 2001 ENGEL: BALTIC AMBER BEES 177

APPENDIX 2 Tribal Classi®cation and Geological Distribution of Bees The following outline presents the tribal classi®cation of bees adopted by the present author based on continuing cladistic investigations into the higher-level phylogeny of Apoidea (®gs. 122, 123). Some of these analyses have been presented above while others will be detailed in forthcoming papers. Those groups presently recorded from the geological record are followed by the standard geological abbreviation for their oldest epoch/stage [e.g., although numerous Miocene to Eocene fossils exist for Meliponini only Cretaceous/Maastrichtian (K/Maa) is listed owing to a single, older fossil from this period]. Compression fossils are indicated in boldface by CF, amber inclusions by A. Daggers (²) denote higher groups that are extinct. 178 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

APPENDIX 2Ð(Continued ) 2001 ENGEL: BALTIC AMBER BEES 179

APPENDIX 2Ð(Continued ) 180 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

APPENDIX 3 Catalog of Family- and Genus-Group Names nus: Glyptapis Cockerell, 1909a. Stem: Glyptap-. for Fossil Bees Megachilidae: Megachilinae [M86/97±67.1]. Melikertini Engel, 2001: 112. Type genus: Me- The following catalog presents all known fam- likertes Engel, 1998a. Stem: Melikert-. Apidae: ily- and genus-group names proposed for fossil Apinae [M86/97±129.3]. bees (amber inclusions and compression fossils). Paleomelittidae Engel, 2001: 41. Type genus: Not all of the names are currently recognized as Paleomelitta Engel, 2001. Stem: Paleomelitt-. Pa- valid (e.g., Sophrobombus is a synonym of Pro- leomelittidae [M86/97±57.1]. tobombus; Paleoeuglossa is a synonym of Eufrie- Protolithurgini Engel, 2001: 51. Type genus: sea) or are con®dently assigned to higher cate- Protolithurgus Engel, 2001. Stem: Protolithug-. gories (e.g., Protomelecta); thus this list should Megachilidae: Lithurginae [M86/97±61.1]. not be taken as a classi®cation. At the end of the list I have included two genus-group names orig- Genus-Group Names inally proposed as fossil bees but subsequently (47 names) recognized to be insects other than bees. A catalog of the world's species of fossil bees (both am- Anthophorites Heer, 1849: 97. Type species: ber inclusions and compression fossils) will be Anthophorites mellona Heer, 1849, by designation presented elsewhere (Engel, in prep.). of Cockerell, 1909a. Apidae: Anthophorini?. The format is generally that of Michener (1986) Apiaria Germar, 1839: 210. Type species: Api- for family-group names and Michener (1997) for aria dubia Germar, 1839, monobasic. Megachil- genus-group names. For family-group names I idae: Osmiini?. have indicated the higher group to which a given Bombusoides Motschulsky, 1856: 28. Type taxon belongs. The number that indicates the lo- species: Bombusoides mengei Motschulsky, 1856, cation of the name in the system of Michener monobasic. Incertae sedis. (1986: with additions and corrections by Miche- Boreallodape Engel, 2001: 78. Type species: ner, 1997) is appended at the end of each entry. Boreallodape baltica Engel, 2001, original des- The citation ``Engel (2001)'' in the following ignation. Xylocopinae: Boreallodapini. list refers to the present monograph and those Calyptapis Cockerell, 1906: 41. Type species: names newly proposed in the body of the text; Calyptapis ¯orissantensis Cockerell, 1906, mono- thus, this reference will not be found in the bib- basic. Apidae: Bombini. liography. Cascapis Engel, 1999c: 187. Type species: Apis armbrusteri Zeuner, 1931, monobasic and original designation, isotypic with Hauffapis. Proposed as Family-Group Names a subgenus of Apis.Apidae: Apini. (10 names) Chalcobombus Cockerell, 1908b: 326. Type species: Chalcobombus humilis Cockerell, 1908b Boreallodapini Engel, 2001: 77. Type genus: [ϭ Protobombus indecisus Cockerell, 1908b], by Boreallodape Engel, 2001. Stem: Boreallodap-. designation of Cockerell, 1909b; isotypic with Apidae: Xylocopinae [M86/97±120.2]. Protobombus Cockerell, 1908b, by synonymy. Chalicodomopsini Engel, 1999d: 4. Type ge- Apidae: Apinae: Electrapini. nus: Chalicodomopsis Engel, 1999d. Stem: Chal- Chalicodomopsis Engel, 1999d: 3. Type spe- icodomops-. Megachilidae: Megachilinae [M86/ cies: Megachile (Chalicodomopsis) glaesaria En- 97±67.2]. Nomen nudum. gel, 1999d, monobasic and original designation. Ctenoplectrellina Engel, 2001: 54. Type ge- Proposed as a subgenus of Megachile. Megach- nus: Ctenoplectrella Cockerell, 1909a. Stem: ilidae: Megachilini. Ctenoplectrell-. Megachilidae: Megachilinae Cretotrigona Engel, 2000b: 3. Type species: [M86/97±67.3]. Trigona (Trigona) prisca Michener and Grimaldi, Electrapina Engel, 1998a: 99. Type genus: 1988a, monobasic and original designation. Api- Electrapis Cockerell, 1908b. Stem: Electrap-. Ap- dae: Meliponini. idae: Apinae [M86/97±129.1]. Ctenoplectrella Cockerell, 1909a: 314. Type Electrobombini Engel, 2001: 88. Type genus: species: Ctenoplectrella viridiceps Cockerell, Electrobombus Engel, 2001. Stem: Electrobomb-. 1909a, monobasic. Megachilidae: Megachilinae: Apidae: Apinae [M86/97±129.2]. Osmiini. Eomacropidini Engel, 2001: 46. Type genus: Cyrtapis Cockerell, 1908a: 339. Type species: Eomacropis Engel, 2001. Stem: Eomacropid-. Cyrtapis anomalus Cockerell, 1908a, monobasic. Melittidae: Macropidinae [M86/97±57.2]. Halictidae: Halictini. Glyptapinae Cockerell, 1909b: 13. Type ge- Eckfeldapis Lutz, 1993: 180. Type species: 2001 ENGEL: BALTIC AMBER BEES 181

Eckfeldapis electrapoides Lutz, 1993, monobasic Liotrigonopsis rozeni Engel, 2001, monobasic and and original designation. Apidae: Apinae: Elec- original designation. Apidae: Meliponini. trapini. Lithandrena Cockerell, 1906: 44. Type spe- Eickwortapis Michener and Poinar, 1996 cies: Lithandrena saxorum Cockerell, 1906, [1997]: 354. Type species: Eickwortapis domini- monobasic. Andrenidae: Andreninae?. cana Michener and Poinar, 1996, monobasic and Lithanthidium Cockerell, 1911b: 225. Type original designation. Halictidae: Caenohalictini. species: Lithanthidium pertriste Cockerell, 1911b, Electrapis Cockerell, 1908b: 326. Type spe- monobasic. Megachilidae: Anthidiini. cies: Apis meliponoides Buttel-Reepen, 1906, by Melikertes Engel, 1998a: 95. Type species: designation of Cockerell, 1909b. Apidae: Api- Electrapis (Melikertes) stilbonota Engel, 1998a, nae: Electrapini. original designation. Proposed as a subgenus of Electraugochlora Engel, 2000a: 32. Type spe- Electrapis. Apidae: Apinae: Melikertini. cies: Augochlora (Electraugochlora) leptoloba Meliponorytes Tosi, 1896: 352. Type species: Engel, 2000a. Proposed as a subgenus of Augo- Meliponorytes succini Tosi, 1896, by designation chlora. Halictidae: Augochlorini. of Sandhouse, 1943. Apidae: Meliponini. Electrobombus Engel, 2001: 88. Type species: Melissites Engel, 2001: 129. Type species: Mel- Electrobombus samlandensis Engel, 2001, mono- issites trigona Engel, 2001, monobasic and orig- basic and original designation. Apidae: Apinae: inal designation. Apidae: Apinae: Melikertini. Electrobombini. Oligochlora Engel, 1996 [1997]: 336. Type Electrolictus Engel, 2001: 38. Type species: species: Oligochlora eickworti Engel, 1996, orig- Electrolictus antiquus Engel, 2001, monobasic inal designation. Halictidae: Augochlorini. and original designation. Halictidae: Halictini. Paleoeuglossa Poinar, 1998 [1999]: 30. Type Eomacropis Engel, 2001: 46. Type species: species: Paleoeuglossa melissi¯ora Poinar, 1998, monobasic and original designation. Apidae: Eomacropis glaesaria Engel, 2001, monobasic Euglossini. and original designation. Melittidae: Macropi- Paleomelitta Engel, 2001: 42. Type species: dinae: Eomacropidini. Paleomelitta nigripennis Engel, 2001, monobasic Glaesosmia Engel, 2001: 75. Type species: and original designation. Paleomelittidae. Glaesosmia genalis Engel, 2001, monobasic and Pelandrena Cockerell, 1909d: 159. Type spe- original designation. Megachilidae: Megachili- cies: Pelandrena reducta Cockerell, 1909d, nae: Osmiini. monobasic. Andrenidae: Andreninae?. Glyptapis Cockerell, 1909a: 314. Type species: Priorapis Engel, 1999c: 188. Type species: Glyptapis mirabilis Cockerell, 1909a, monobasic. Apis vetusta Engel, 1998c, monobasic and origi- Megachilidae: Megachilinae: Osmiini. nal designation. Proposed as a subgenus of Apis. Hauffapis Armbruster, 1938: 37. Type species: Apidae: Apini. Hauffapis scheuthlei Armbruster, 1938 [ϭApis Probombus Piton, 1940: 218. Type species: armbrusteri Zeuner, 1931], by designation of Zeu- Probombus hirsutus Piton, 1940, monobasic. Ap- ner and Manning, 1976, isotypic with Cascapis. idae: Bombini. Unavailable as no type species was originally des- Prohalictus Armbruster, 1938: 48. Type spe- ignated (required after 1930 by ICZN, 1999b: Art. cies: Prohalictus schemppi Armbruster, 1938, 13.3). Note: Zeuner and Manning's action does monobasic. Halictidae: Halictini. not validate the name with themselves as authors Proplebeia Michener, 1982: 44. Type species: as it was in the synonymy of the genus. Apidae: Trigona (Liotrigona) dominicana Wille and Chan- Apini. dler, 1964, monobasic and original designation. Kelneriapis Sakagami, 1978 (June): 232. Type Proposed as a subgenus of Trigona. Apidae: Me- species: Hypotrigona eocenica Kelner- Pillault, liponini. 1969a, monobasic, isotypic with Kelnermelia. Protobombus Cockerell, 1908b: 326. Type spe- Proposed as a subgenus of Tetragonula. Apidae: cies: Protobombus indecisus Cockerell, 1908b, Meliponini. monobasic [also designated by Cockerell, 1909b], Kelnermelia Moure In Moure and Camargo, isotypic with Chalcobombus Cockerell, 1908b, by 1978 (November): 565. Type species: Hypotri- synonymy. Apidae: Apinae: Electrapini. gona eocenica Kelner-Pillault, 1969a, monobasic Protolithurgus Engel, 2001: 51. Type species: and original designation, isotypic with Kelneriap- Protolithurgus ditomeus Engel, 2001, monobasic is. Apidae: Meliponini. and original designation. Megachilidae: Lithur- Libellulapis Cockerell, 1906: 42. Type species: ginae: Protolithurgini. Libellulapis antiquorum Cockerell, 1906, mono- Protomelecta Cockerell, 1908a: 341. Type spe- basic. Andrenidae: Panurginae?. cies: Protomelecta brevipennis Cockerell, 1908a, Liotrigonopsis Engel, 2001: 135. Type species: monobasic. Apidae: Melectini?. 182 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Roussyana Manning, 1960 [1961]: 306. Type Thaumastobombus Engel, 2001: 109. Type species: Apis palmnickenensis Roussy, 1937, orig- species: Thaumastobombus andreniformis Engel, inal designation. Proposed as a subgenus of Elec- 2001, monobasic and original designation. Api- trapis. Apidae: Apinae: Melikertini. dae: Apinae: Electrapini. Soliapis Engel, 2000a: 47. Type species: Oli- gochlora (Soliapis) rozeni Engel, 2000a, original designation. Proposed as a subgenus of Oligo- chlora. Halictidae: Augochlorini. Non-Bees Sophrobombus Cockerell, 1908b: 326. Type species: Sophrobombus fatalis Cockerell, 1908b, Palaeapis Hong, 1984: 37. Type species: Pa- monobasic [also designated by Cockerell, 1909c]. laeapis beiboziensis Hong, 1984, monobasic and Apidae: Apinae: Electrapini. original designation. Originally proposed in Api- Succinapis Engel, 2001: 115. Type species: dae; presently a junior synonym of Archisphex Succinapis goeleti Engel, 2001, original designa- (Rasnitsyn et al., 1998). Sphecidae. tion. Apidae: Apinae: Melikertini. Sinostigma Hong, 1983: 9. Type species: Si- Synapis Cockerell, 1907: 229. Type species: nostigma spinalata Hong, 1983, monobasic and Apis (Synapis) henshawi Cockerell, 1907, mono- original designation. Originally proposed in Mel- basic. Proposed as a subgenus of Apis. Apidae: ittidae; later transferred to Megachilidae (Hong, Apini. 1985). Vespidae?.

APPENDIX 4 Full Journal Titles Abbreviated in References Aust. Zool. Australian Zoologist Belg. J. Entomol. Belgian Journal of Entomol- The following list provides full journal titles for ogy abbreviations in the References section. Abbre- Bernstein-Forsch. Bernstein-Forschungen viations are listed in alphabetical order in bold- Biol. J. Linn. Soc. Biological Journal of the face, followed by the expanded title. Speci®c se- Linnean Society ries or report numbers are replaced in this list by Biol. Zentbl. Biologisches Zentralblatt ``#''. Biul. Inst. Geol. Biuletyn Instytutu Geologi- Acta Zootaxon. Sinica Acta Zootaxonomica cznego Sinica Bol. Soc. Amig. Cienc. Nat. ``Kraglievich-Fon- Am. Chem. Soc. American Chemical Society tana'' BoletõÂn de la Sociedad Amigos de las Am. J. Bot. American Journal of Botany Ciencias Naturales ``Kraglievich-Fontana'' Am. Midl. Nat. American Midland Naturalist Bol. Univ. Fed. ParanaÂ, Zool. # Boletim da Am. Mus. Novitates American Museum Novi- tates Universidade Federal do ParanaÂ, Zoologia Ann. Entomol. Soc. Am. Annals of the Ento- Bot. Gaz. Botanical Gazette mological Society of America Bull. Am. Mus. Nat. Hist. Bulletin of the Ann. Geol. Pays Helleniques Annales Geolo- American Museum of Natural History giques des Pays Helleniques Bull. Br. Mus. Nat. Hist. (Entomol.) Bulletin Ann. Mag. Nat. Hist., ser. # Annals and Mag- of the British Museum of Natural History (En- azine of Natural History, series # tomology) Ann. Missouri Bot. Gard. Annals of the Mis- Bull. Br. Mus. Nat. Hist. (Geol.) Bulletin of souri Botanical Garden the British Museum of Natural History (Geol- Ann. Natal Mus. Annals of the Natal Museum ogy) Ann. Soc. Entomol. Fr. Annales de la SocieÂteÂ Bull. Mus. Comp. Zool. Bulletin of the Muse- Entomologique de France um of Comparative Zoology Annu. Rev. Ecol. Syst. Annual Review of Ecol- Bull. Nat. Hist. Mus., London (Geol.) Bulletin ogy and Systematics of the Natural History Museum, London (Ge- Annu. Rev. Entomol. Annual Review of En- ology) tomology Bull. Pol. Acad. Sci. Bulletin of the Polish Appl. Spectrosc. Rev. Applied Spectroscopy Academy of Sciences Reviews Bull. Soc. Entomol. France Bulletin de la So- Arch. Bienenkd. Archiv fuÈr Bienenkunde cieÂteÂ Entomologique de France Arq. Mus. Parana. Arquivos do Museu Par- Bull. Tianjin Inst. Geol. Miner. Res. Bulletin anaense of the Tianjin Institute of Geology and Mineral Aust. J. Sci. Australian Journal of Science Resources 2001 ENGEL: BALTIC AMBER BEES 183

Bull. Zool. Nomencl. The Bulletin of Zoologi- AÊ rsskrift, 2 Afdelning, Medicin samt Matema- cal Nomenclature tiska och Naturvetenskapliga AÈ mnen [Parallel Can. Entomol. The Canadian Entomologist serial title: Acta Universitatis Lundensis] Cas. Morav. Mus. Brne CÆ asopis MoravskeÂho Mag. Insektenkd. Magazin fuÈr Insektenkunde musea v Brne Mainzer Natwiss. Arch. Mainzer naturwissen- ChaÂcaras Quint. (SaÄo Paulo) ChaÂcaras e Quin- schaftliches Archiv tais, SaÄo Paulo Mem. Beijing Nat. Hist. Mus. Memoirs of the Contrib. Am. Entomol. Inst. Contributions of Beijing Natural History Museum the American Entomological Institute Mitt. Geol.-PalaÈontol. Inst. Univ. Hambg. Mit- Contrib. Geol., Univ. Wyoming. Contribu- teilungen aus dem Geologisch-PalaÈontologisch- tions to Geology, University of Wyoming en Institut der UniversitaÈt Hamburg Cretac. Res. Cretaceous Research Mitt. Zool. Mus. Berl. Mitteilungen aus dem Dalle Mem. Soc. Entomol. Ital. Dalle Memorie Zoologischen Museum in Berlin della Societa Entomologica Italiana Mol. Phylogenet. Evol. Molecular Phylogenet- Denkschr. Kaiserl. Akad. Wiss., Math.-Na- ics and Evolution twiss. Cl. Denkschriften der Kaiserlichen MuÈnster. Forsch. Geol. PalaÈontol. MuÈnster- Akademie der Wissenschaften [Wien], Mathe- sche Forschungen zur Geologie und PalaÈonto- matisch-Naturwissenschaftliche Classe logie Doc. Nat. Documenta Naturae Mus. North. Arizona Bull. Museum of North- Dtsch. Entomol. Z. Detusche Entomologische ern Arizona Bulletin Zeitschrift Natl. Park Serv., Paleontol. Res. [Tech. Rep. Entomol. Entomologist #] National Park Service, Paleontological Re- Entomol. Mag. Entomological Magazine search [Technical Report] Entomol. News Entomological News Neue Denkschr. Allg. Schweiz. Gesell. Ges. Na- Entomol. Obozr. Entomologicheskoye Obozre- twiss. Neue Denkschriften der Allgemeinen niye Schweizerischen Gesellschaft fuÈr die gesa- Entomol. Rev. Entomological Review mmten Naturwissenschaften Entomol. Scand. Entomologica Scandinavica Nova Acta Acad. C. Leopold.-Carol. Germ. EPHE Biol. Evol. Insectes EPHE Biologie et Nat. Cur. Nova Acta Academiae Caesarea Evolution des Insectes Leopoldino-Carolinae Germanicum Naturae Etude Entomol. Etude Entomologiques Curiosorum Fortschr. Geol. Palaeontol. Fortschritte der Nova Acta Leopold. (Kaiserl. Leopold.-Carol. Geologie und Palaeontologie Dtsch. Akad. Naturf.) Nova Acta Leopoldi- Gaz. Apic., Montfavet La Gazette Apicole, na (Kaiserlich Leopoldinisch-Carolinisch Montfavet Deutschen Akademie der Naturforscher) J. Anim. Ecol. Journal of Animal Ecology Orient. Insects Oriental Insects J. Baltic Stud. Journal of Baltic Studies Palaeogeogr., Palaeoclimatol., Palaeoe- J. Evol. Biol. Journal of Evolutionary Biology col. Palaeogeography, Palaeoclimatology, Pa- J. Exp. Biol. Journal of Experimental Biology laeoecology J. Fac. Sci., Hokkaido Univ., ser. # Palaeontol. Z. Palaeontologische Zeitschrift (Zool.) Journal of the Faculty of Science, Pan-Pac. Entomol. Pan-Paci®c Entomologist Hokkaido University, series # (Zoology) Pap. Avulsos Zool. (SaÄo Paulo) PapeÂis avulsos J. Hym. Res. Journal of Hymenoptera Research de Zoologia, SaÄo Paulo J. Kansas Entomol. Soc. Journal of the Kansas Philipp. Entomol. Philippine Entomologist Entomological Society Philos. Trans. R. Soc. London, ser. B, Biol. J. Kansas Entomol. Soc., Suppl. Journal of the Sci. Philosophical Transactions of the Royal Kansas Entomological Society, Supplement Society of London, series B, Biological Scienc- J. New York Entomol. Soc. Journal of the New es York Entomological Society Plant Syst. Evol.ϭPlant Systematics and Evolu- J. Paleontol. Journal of Paleontology tion J. Trop. Ecol. Journal of Tropical Ecology Plateau J., Mus. North. ArizonaϭPlateau Jour- Jahrb. Nassau. Ver. Naturkd. JahrbuÈcher des nal, Museum of Northern Arizona Nassauischen Vereins fuÈr Naturkunde Proc. Acad. Nat. Sci., Philadelphia Proceedings Jahrb. Ver. Naturkd. Herzogthum Nassau of the Academy of Natural Sciences, Philadel- JahrbuÈcher des Vereins fuÈr Naturkunde im Her- phia zogthum Nassau Proc. Natl. Acad. Sci., U.S.A. Proceedings of Linzer Biol. Beitr. Linzer Biologische BeitraÈge the National Academy of Sciences of the Unit- Lunds Univ. AÊ rskr., 2 Afd. Lunds Universitets ed States of America 184 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Proc. First Intl. Palaeoentomol. Conf., Syst. Entomol. Systematic Entomology Moscow Proceedings of the First Internation- Syst. Zool. Systematic Zoology al Palaeoentomological Conference, Moscow Tr. Paleontol. Inst. Akad. Nauk SSSR Trudy [Russia] Paleontologicheskogo Instituta Akademii Nauk Proc. VI Congr. IUSSI, Bern Proceedings VI SSSR Congress of the International Union for the Trans. Am. Entomol. Soc. Transactions of the Study of Social Insects, Bern [Switzerland] American Entomological Society Proc. 13th Intl. Congr. IUSSI, Adelaide- Trans. Entomol. Soc. London Transactions of Proceedings of the 13th International Congress the Entomological Society of London of the International Union for the Study of So- Trans. Norfolk Norwich Nat. Soc. Trans- cial Insects, Adelaide [Australia] actions of the Norfolk and Norwich Naturalist's Proc. U.S. Natl. Mus. Proceedings of the Unit- Society ed States National Museum Univ. California Publ. Entomol. University of Prof. Pap. Stratigr. Paleontol. Professional Pa- California Publications in Entomology pers of Stratigraphy and Paleontology Univ. Colorado Stud., Ser. Bibliogr. University Rev. Biol. Trop. Revista de BiologõÂa Tropical of Colorado Studies, Series in Bibliography Rev. Palaeobot. Palynol. Review of Palaeobo- Univ. Kansas Nat. Hist. Mus. Sci. Pap. Scien- tany and Palynology ti®c Papers, Natural History Museum, Univer- Rev. Zool. Bot. Afr. Revue de Zoologie et de sity of Kansas Botanique Africaines Univ. Kansas Nat. Hist. Mus. Spec. Riv. Ital. Paleontol., Bologna Rivista Italiana Publ. University of Kansas Natural History di Paleontologia, Bologna [Italy] Museum Special Publication Rocky Mountain Sec., Geol. Soc. Am. Reg. Univ. Kansas Sci. Bull. University of Kansas Science Bulletin Meeting Rocky Mountain Section, Geologi- U.S. Geol. Surv. Bull., Washington United cal Society of America Regional Meeting States Geological Survey Bulletin, Washington Russian Acad. Sci. Russian Academy of Sci- [D.C.] ences Usp. Sovrem. Biol., Moscow Uspechi sovre- Schr. Naturf. Gesell. Danzig Schriften der Na- mennoi Biologii, Moscow turforschenden Gesellschaft in Danzig È Verh. XI Intl. Kongr. Entomol., Wien Verhan- Schr. Phys.-Okon. Gesell. Schriften der Phy- dlungen XI Internationaler Kongress fuÈr Ento- sikalisch-oÈkonomischen Gesellschaft mologie, Wien [Vienna] Sitzungsber. Akad. Wiss. Wien, Math.-Natwiss. Verh. Naturhist. Ver. Preuss. Rheinlande Kl. Sitzungsberichte der Akademie der Wis- Westphalen Verhandlungen des Naturhisto- senschaften in Wien [Vienna], Mathematische- rischen Vereines der Preussischen Rheinlande Naturwissenschaftliche Klasse und Westphalen Smithson. Misc. Coll. Smithsonian Miscella- Wiener Ber. Natwiss. Kunst Wiener berichte neous Collections uÈber Naturwissenschaft in der Kunst Sociobiol. Sociobiology Zool. Inst., Acad. Sci. Zoological Institute, Stettiner Entomol. Ztg. Stettiner Entomologis- Academy of Sciences che Zeitung Zool. J. Linn. Soc. Zoological Journal of the Stud. Entomol. Studia Entomologia Linnean Society Stud. Geol. Salmanticensia (Stud. Palaeoche- Zool. Scr. Zoologica Scripta loniol.) Studia Geologica Salmanticensia Z. Syst. Hym. Dipt. Zeitschrift fuÈr systematis- (Studia Palaeocheloniologica) che Hymenopterologie und Dipterologie 2001 ENGEL: BALTIC AMBER BEES 185

INDEX OF TAXONOMIC NAMES hirsutus (Protobombus), 106,108,190 humilis (Protobombus; ϭindecisus), 101 Page of original reference in Roman typeface; ®gures Hypotrigona, 134 in italics. Speci®c names are cited individually, with cur- indecisus (Protobombus), 100,101,102,191 rent generic combination indicated in parentheses. Kelneriapis, 134 Names in the family-group are in capitals. Kelnermelia (ϭKelneriapis), 134 krishnorum (Electrapis), 94,94,96 Andrena, 138 Liotrigonopsis, 135 andreniformis (Thaumastobombus), 109,110±114,190 LITHURGINAE,50 antiquus (Electrolictus), 38,39,40,41,186 MACROPIDINAE,46 APIDAE,76 martialis (Electrapis), 92,93 APIFORMES,35 Megachile, 75 MEGACHILIDAE,49 APINAE,86 MEGACHILINAE,53 Apis, 94,98,124,131 Melikertes, 123 APOIDEA,34 MELIKERTINI, 112 apoides (Protobombus; ϭindecisus), 101 MELIPONINI, 133 baltica (Boreallodape), 79,78±80,189 meliponoides (Electrapis), 98,98,191 basilaris (Protobombus), 105,106 Melissites, 129 Bombus, 138 MELITTIDAE,44 Bombusoides, 138 MELITURGULINI, 177,179 bombusoides (Electrapis; ϭtornquisti), 96 mengei (Bombusoides), 139 Boreallodape,78 micheneri (Succinapis), 118,120,192 minuta (Roussyana; ϭpalmnickenensis), 132 BOREALLODAPINI,77 mirabilis (Glyptapis), 2,55,57,58,187 carbonarius (``Bombus''), 138 mollyae (Boreallodape), 81,81,82,189,190 Chalcobombus (ϭProtobombus), 100 muscorum (``Bombus''), 138 clypeatus (Melikertes), 128,192 neglecta (Glyptapis; ϭfuscula), 64 cockerelli (Ctenoplectrella), 71,72 nigripennis (Paleomelitta), 42,42±44,186,187 cockerelli (Electrapis; ϭtornquisti), 96 OSMIINA,54 Ctenoplectrella,68 OSMIINI,54 CTENOPLECTRELLINA,54 Paleomelitta, 42 Dasypoda, 64 PALEOMELITTIDAE,41 palmnickenensis (Roussyana), 131 densopunctata (Glyptapis), 62,63,188 PENAPINI,37 dentata (Ctenoplectrella; ϭviridiceps), 69 proavus (Melikertes), 124 disareolata (Glyptapis), 59,60±62,187 proboscidea (Succinapis), 121,122,192 ditomeus (Protolithurgus), 51,52,187 Protobombus, 99 Eckfeldapis (ϭElectrapis), 92 PROTOLITHURGINI,51 ELECTRAPINI,90 Protolithurgus, 51 Electrapis, 92 pusillus (``Bombus''), 138 ELECTROBOMBINI,88 REDIVIVINI,45 Electrobombus, 88 reducta (Glyptapis; ϭfuscula), 64 reticulata (Glyptapis; ϭfuscula), 64 Electrolictus, 38 Roussyana, 131 eocenica (Kelneriapis), 133,134,192 rozeni (Liotrigonopsis), 136,136,137,192 EOMACROPIDINI,46 samlandensis (Electrobombus), 88,89,90,190 Eomacropis, 46 Sophrobombus (ϭProtobombus), 100 fatalis (Protobombus), 103,104 splendens (Ctenoplectrella; ϭviridiceps), 69 fuscula (Glyptapis), 62,64,65,66,188 stilbonotus (Melikertes), 126,125±127 genalis (Glaesosmia), 75,75 striebichi (Boreallodape), 82,83±86,189 glaesaria (Eomacropis), 47,47,48,186 Succinapis, 115 Glaesosmia, 75 Tetragonula, 134 Thaumastobombus, 109 GLYPTAPINA,54 tornquisti (Electrapis), 96 Glyptapis, 56 Trigona, 124,132,134 goeleti (Succinapis), 115,116±118,192 trigona (Melissites), 129,129±131,191 grimaldii (Ctenoplectrella), 73,74,188 tristellus (Protobombus), 107 HALICTIDAE,36 TRYPETINA,54 HALICTINAE,36 viridiceps (Ctenoplectrella), 68,69,70,188 HALICTINI,37 wrisleyi (``Andrena''), 138 hermenaui (Electrapis; ϭtornquisti), 96 XYLOCOPINAE,77 186 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Plate 1. Families Halictidae, Paleomelittidae, and Melittidae. a. Electrolictus antiquus Engel, holotype female (MB.I.1952 ZMHB), right lateral view. b. E. antiquus, holotype female, left lateral view. c. Paleomelitta nigripennis Engel, holotype female (B-JH 101 AMNH), frontodorsal oblique view. d. P. nigripennis, holotype female, dorsal view. e. Eomacropis glaesaria Engel, holotype female (SAMH), frontal view of head. f. E. glaesaria, holotype female, left lateral view with arrow indicating staphyliniform larva on dorsum. 2001 ENGEL: BALTIC AMBER BEES 187

Plate 2. Families Paleomelittidae and Megachilidae (Lithurginae and Glyptapina). a. Amber block with inclusions of Paleomelitta nigripennis Engel (B-JH 101 AMNH), position of holotype indicated by arrow (visible dimensions of block: width 5.5 cm, length 13.5 cm). b. Protolithurgus ditomeus Engel, holotype female (B-W 157 AMNH), dorsal view. c. P. ditomeus, holotype female, right lateral view. d. P. ditomeus, holotype female, frontal view of head. e. Glyptapis mirabilis Cockerell, holotype female (K72 IMGP), dorsal view. f. G. disareolata Engel, holotype female (B-JH 104 AMNH), ventral view. 188 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Plate 3. Family Megachilidae: Glyptapina and Ctenoplectrellina. a. Glyptapis fuscula Cockerell, female (ZMUC), frontal view of face. b. G. densopunctata Engel, holotype female (B-W 161 AMNH), left ventrolateral oblique view. c. Ctenoplectrella viridiceps Cockerell, male (NB.I.1949 ZMHB), left lateral view. d. C. viridiceps, male, ventral view. e. C. viridiceps, neotype female (B-JH 95 AMNH), right frontolateral oblique view. f. C. grimaldii Engel, holotype female (B-JH 88 AMNH), right lateral view. 2001 ENGEL: BALTIC AMBER BEES 189

Plate 4. Family Apidae: Xylocopinae. a. Boreallodape baltica Engel, holotype female (B-JH 152 AMNH), dorsal view. b. B. baltica, holotype female, ventral view. c. B. striebichi Engel, holotype female (B-BS 153 AMNH), dorsal view. d. B. striebichi, holotype female, ventral view. e. B. mollyae Engel, holotype female (B-JH 81 AMNH), right lateral view. f. Amber block with inclusions of B. striebichi, holotype female is the uppermost specimen to the left of a ¯ower fragment and highlighted by light source (visible dimensions of block: maximal width 2.1 cm, length 3.7 cm). 190 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Plate 5. Family Apidae: Xylocopinae, Electrobombini, and Electrapini. a. Boreallodape mollyae Engel, paratype female (19948 ZMPA), dorsal view. b. B. baltica Engel, holotype female (B-JH 152 AMNH), left lateral view. c. Electrobombus samlandensis Engel, holotype female (B-JH 94 AMNH), dorsal view. d. Protobombus hirsutus (Cockerell), neotype female (B-JH 92 AMNH), frontolateral oblique view. e. E. samlandensis, holotype female, frontal view of head. f. Thaumastobombus andreniformis Engel, holotype female (B-JH 164 AMNH), left lateral view. 2001 ENGEL: BALTIC AMBER BEES 191

Plate 6. Family Apidae: Electrapini and Melikertini. a. Protobombus indecisus Cockerell, neotype female (B-JH 98 AMNH), right lateral view; neotype is individual in left of photograph, the head of a second specimen is visible along the lower margin near the hind wing apex of the neotype. b. P. indecisus, neotype female, frontal view of head. c. Electrapis meliponoides (Buttel-Reepen), neotype female (B-JH 97 AMNH), dorsal view. d. Melissites trigona Engel, holotype female (B-JH 102 AMNH), left lateral view. 192 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 259

Plate 7. Family Apidae: Melikertini and Meliponini. a. Melikertes clypeatus Engel, holotype female (B-JH 77 AMNH), right lateral view. b. Succinapis proboscidea Engel, paratype female (B-JH 99 AMNH), left lateral view. c. S. micheneri Engel, holotype female (B-JH 103 AMNH), right lateral view (arrow indicates clypeal protusion). d. S. goeleti Engel, holotype female (B-JH 90 AMNH), right lateral view. e. Kelneriapis eocenica (Kelner-Pillault), holotype female (NB.I.1946 ZMHB), left lateral view. f. Liotrigonopsis rozeni Engel, holotype female (B-JH 79 AMNH), right lateral view.