Primobucco mcgrewi (Aves: Coracii) from the Green River Formation: New Anatomical Data from the Earliest Constrained Record of Stem Rollers Author(s): Daniel T. Ksepka and Julia A. Clarke Source: Journal of Vertebrate Paleontology, Vol. 30, No. 1 (Jan., 2010), pp. 215-225 Published by: Taylor & Francis, Ltd. on behalf of The Society of Vertebrate Paleontology Stable URL: http://www.jstor.org/stable/20627163 . Accessed: 30/03/2014 13:08

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This content downloaded from 128.83.63.20 on Sun, 30 Mar 2014 13:08:38 PM All use subject to JSTOR Terms and Conditions Journal of Vertebrate Paleontology 30(l):215-225, January 2010 ? 2010 by the Society of Vertebrate Paleontology

ARTICLE

PRIMOBUCCO MCGREWI (AVES: CORACII) FROM THE EOCENE GREEN RIVER FORMATION: NEW ANATOMICAL DATA FROM THE EARLIEST CONSTRAINED RECORD OF STEM ROLLERS

DANIEL T. KSEPKA*1'2 and JULIA A. CLARKE121 department ofMarine, Earth, and Atmospheric Sciences, Campus Box 8208, North Carolina State University, Raleigh, North Carolina 27695, U.S.A., [email protected]; department of Paleontology, North Carolina StateMuseum ofNatural Sciences, Raleigh, North Carolina 27601, U.S.A.

ABSTRACT?The Eocene Green River Formation provides one of the richest records of fossil worldwide. As part of a reevaluation of this avifauna, we describe 12 new specimens of the stem roller Primobucco mcgrewi from the well-dated (51.66 ? 0.09 Ma) Fossil Butte Member (FBM) of the Green River Formation ofWyoming. FBM specimens represent most of avian diversity in the Green River Formation and include the oldest well-constrained record of the roller lineage (Coracii). These fossils provide new anatomical data, including the first observations on the palate, and broaden our understanding of the distribution, abundance, and taphonomy of P. mcgrewi. Using museum records and lithological comparisons, 14 of the 15 known P. mcgrewi specimens can now be assigned to specific quarries within Fossil Lake. The species is now known from five distinct localities representing both nearshore and mid-lake environments and accounts for >10% of the 148 FBM avian specimens reviewed in this study. Pectoral elements are disproportionately represented in the FBM P. mcgrewi specimens, and more than half of the sample exhibits broken elements. These new fossils and other key specimens from the Eocene of North America and Europe clarify our understanding of the evolution of the clade Coracii. Extant parts of this lineage (i.e., and Brachypteraciidae) have specialized ecologies and restricted Old World distributions, whereas stem representatives appear more generalized and were a major component of some North American avifaunas.

INTRODUCTION Primobucco is the smallest-bodied and most widespread taxon of stem roller. It includes three species: Primobucco mcgrewi, Pri Rollers (Coracii) are represented by two extant groups: mobucco perneri, and Primobucco frugilegus (Brodkorb, 1970; Coraciidae (true rollers) and Brachypteraciidae (ground rollers). Houde and Olson, 1989; et al, The firstof these Coraciidae are hunters known for their acrobatic Mayr 2004). open-area to be Primobucco was from and are distributed species named, mcgrewi, reported display flights, presently throughoutAsia, Eocene Green River Formation Brodkorb and Australia et deposits by (1970). Europe, Africa, Madagascar, (Fry al., 1992; the was identified as The more terrestrial are Initially, poorly preserved holotype wing Fry, 2001). Brachypteraciidae primar a Houde and Olson leaf-litter and are restricted to (Bucconidae). (1989) subsequently ily foragers entirely Madagas considered the ofPrimobucco difficultto car All extant rollers are characterized holotype mcgrewi place (Langrand, 2001). by within but noted that a referred heads and colorful These birds are Aves, nearly complete spec large plumage. primarily imen indicated that the could have invertebrates and small vertebrates. Stem (USNM 336284) species predaceous, consuming affinities to of Houde and members of the roller reveal that the Brachypteraciidae (Atelornithidae lineage elongate wings et al. described this of Coraciidae and of are re Olson, 1989). Mayr (2004) formally spec elongate legs Brachypteraciidae imen and Primobucco as a stem roller. stricted to those extant clades and recognized mcgrewi (Mayr Mourer-Chauvire, These authors also described two new the of in extinct rollers have European species (Pri 2000). Hence, range ecologies may mobucco and Primobucco from the mid been distinct from thatobserved in true rollers and perneri frugilegus) early living ground dle Eocene Messel and a tarsometatar rollers. deposits assigned partial sus from the early Eocene of Conde-en-Brie, France, to Pri The roller stem lineage is known from an array of taxa in mobucconidae indet. Two specimens of Primobucco frugilegus cluding Eocoracias brachyptera, Geranopterus alatus, and Gera preserve seeds as gut contents (Mayr et al, 2004), and one spec nopterus milneedwardsi from the Eocene Messel and Quercy de imen of Eocoracias brachyptera preserves a single seed within posits ofEurope (Mayr andMourer-Chauvire, 2000) and Paraco the stomach area (Mayr and Mourer-Chauvire, 2000). Hence, racias occidentalis from theGreen River Formation (Clarke et al., basal rollers appear to have had a more omnivorous diet than 2009). Geranopterus bohemicus, from theMiocene of theCzech their extant relatives (Mayr et al, 2004). Among the 12 living Republic, may represent the youngest pre-Holocene record of species of true rollers, only Coracias garrulus (European Roller) Coracii, but is presently known from only a single partial tar is known to habitually consume fruits (grapes and figs; Fry, sometatarsus (Mayr and Mourer-Chauvire, 2000). 2001). Additionally, Coracias cyanogaster (Blue-bellied Roller) has been documented occasionally taking oil-palm nuts (Fry et al, 1992). Brachypteraciidae are entirely predaceous (Lan Corresponding author. ^Current address: Department of Geologi grand, 2001). cal Sciences, Jackson School of Geosciences, The University of Texas As part of a major ongoing reevaluation of the abundant and at 1 Texas U.S.A. Austin, University Station, C1100, Austin, 78713, exceptionally preserved avian specimens from the Fossil Butte [email protected] Member (FBM) of the Eocene Green River Formation, we

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FIGURE 1. Map showing the extent of the Green River Lake Complex during the late early Eocene, modified from Grande and Buchheim (1994). Fossil Lake is enlarged at right, with localities of the Fossil Butte Member that have yielded Primobucco mcgrewi specimens labeled. Locality letters and the distribution of the three major lithotypes (i.e., KRLM, KPLM, and BM) correspond to the system of Grande and Buchheim (1994): A, locality A, Lewis Ranch site 1 (F-l); B, locality B, Lewis Ranch site 2 (F-l); E, locality E, Wyoming State Commercial site 1 (F-l); H, locality H, Thompson Ranch (F-2); K, locality K, Warfield Springs (F-2 equivalent deposits).

identified 12 undescribed fossils assignable to Primobucco mc this species has previously come from a third,nearly complete grewi. The FBM deposits have yielded the majority of avian referred skeleton (USNM 336284; Houde and Olson, 1989;Mayr species described thus far from theGreen River Formation, and et al, 2004). Though most elements are intact inUSNM 336284, an many additional species remain undescribed. They represent preservation is poor in several key regions of the skeleton (e.g., essentially contemporaneous sample of nearshore and mid-lake pectoral girdle) and the skull only allows assessment in lateral new our deposits fromFossil Lake, the smallest of themajor Green River view. Thus, the specimens fill in important gaps in knowl lakes (Fig. 1;McGrew and Casilliano, 1975;Grande, 1984, 1994, edge of themorphology of Primobucco mcgrewi. 2001; Buchheim, 1994a, 1998; Grande and Buchheim, 1998). Ar guably, this is the best sample and closest approximation of a sin gle avifauna from theEocene ofNorth America. The vastmajor ityof avian fossils from theGreen River Formation are derived TAXONOMIC REMARKS from themiddle unit of the FBM. The bound of themid upper The taxonomic of "Primobucconidae" is This a history complex. dle unit is K-spar tufffor which Buchheim and Eugster (1998) reflectsan of the of extinct an evolving understanding relationships reported 40Ar/39Ar age of 50.2 ?1.9 Ma. More recently, Smith Eocene taxa, motivated by advances in avian phylogenetics and et al. refined the age of this tuffto 51.66 ? 0.09 Ma from (2008) the discovery of more complete fossils.Until recently, the taxon Gaussian-distributed ap multicrystal analyses (sanidine) yielding Primobucconidae has consistently included a group of species ages with few outliers. The under parent fossil-bearing deposits now understood to represent a with little have been identified to the lower and middle units within polyphyletic assemblage study bearing on the evolutionary historyof rollers (Mayr et al, 2004). theFBM 1994a, (Buchheim, 1998). Brodkorb (1970) named Primobucco mcgrewi from a sin Here, of the of Pri previously unreported aspects morphology gle fragmentary specimen, considering it to be a member of mobucco are described, and the known distribution of mcgrewi the Bucconidae (). Shortly thereafter,Feduccia (1973) this species within Fossil Lake is expanded. Hitherto known from a com named the species "Primobucco" kistneri from more only three specimens, P. mcgrewi is now represented by at least skeleton. Feduccia and Martin transferred "Pri 15 from This now plete (1976) individuals multiple localities. species is recog mobucco" kistneri to "Neanis" kistneri and coined the fam nized as one of themost common of theFossil Lake components ily name Primobucconidae, which they considered to be avifauna. Because the consists of a holotype (UWGM 3299) only long within Galbulae (puffbirds and jacamars). These authors and the firstreferred con rightwing (Brodkorb, 1970) specimen included in the family:Primobucco mcgrewi, "Pri sists of a associated with of the eight species rightwing parts pectoral girdle mobucco" olsoni, Neanis schucherti, "Neanis" kistneri, Uin 14563; et al, most of our of (UWGM Mayr 2004), understanding tornis lucaris, Uintornis marionae, Botauroides parvus, and

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Eobucco brodkorbi. However, subsequent work has revealed InstitutionalAbbreviations?FMNH: Department ofGeology, "Primobucconidae" sensu Feduccia and Martin (1976) to be Field Museum of Natural History, Chicago, Illinois, U.S.A.; polyphyletic. SMF: Forschunginstitut Senckenberg, Frankfurt am Main, Ger Houde and Olson (1989) recognized that "Primobucconidae" many; USNM: National Museum of Natural History, Smithso (sensu Feduccia and Martin, 1976) incorporated taxa from at nian Institution, Washington, D.C, U.S.A.; UWGM: University least three unrelated avian groups. These authors removed ofWyoming Geological Museum, Laramie, Wyoming, U.S.A.; four species (Uintornis lucaris, Uintornis marionae, Botauroides WSGS: Wyoming State Geological Survey, Laramie, Wyoming, parvus, and Eobucco brodkorbi) fromPrimobucconidae and re U.S.A. ferred them to Sandcoleiformes (Houde and Olsen, 1992), a clade now understood to be part of theColiiformes stem group (mouse SYSTEMATIC PALEONTOLOGY birds;Mayr and Peters, 1998). Mayr (2002) subsequently recog Forbes, 1884 nized "Primobucco" olsoni as a stem member of Psittaciformes CORACII Wetmore andMiller, 1926 (parrots) and referred the species to Pulchrapollia (Psittaci PRIMOBUCCO MCGREWI Brodkorb, 1970 formes: Pseudasturidae). Mayr (2005a) also recognized Neanis schucherti as part of Gracilitarsidae, an extinct clade of Pici Holotype?UWGM 3299 (partialwing) formes (woodpeckers, toucans, puffbirds and allies). Referred Specimens?(newly referred specimens indicated see The relationships of "Neanis" kistneri remain uncertain. Fe with asterisks; Tables 1-2 and Figs. 2-5): FMNH PA 345*, duccia (1973) provided essentially no description or diagno FMNH PA 346*, FMNH PA 611*, FMNH PA 724*, FMNH PA sis. However, the presence of a zygodactyl foot clearly pre 733*, FMNH PA 735*, FMNH PA 737*, FMNH PA 738*, FMNH cludes affinitieswith Coracii. As noted by Houde and Olson PA 758*,FMNH PA 759*,UWGM 14563,USNM 336284,WSGS (1989), the holotype specimen differsmarkedly fromNeanis U-93-1A*. schucherti and further lacks important diagnostic features of Locality and Horizon?Fossil Butte Member of the Eocene the familyGracilitarsidae (proximally expanded humerus and Green River Formation, Wyoming. Approximately 51.66 ? 0.09 slender, elongate tarsometatarsus exceeding the humerus in Ma in age (Smith et al, 2008). See Table 1 for quarry data for length). Thus, "Neanis" kistneri should be removed fromNea individual specimens. nis, preferably in the context of a proper diagnosis and complete Emended Diagnosis?The 12 newly referred specimens are description. identical inmorphology and proportions to the previously iden Two incomplete bones from the early Eocene London Clay tified specimens of Primobucco mcgrewi for all anatomical ele were to occurrences common. are previously considered represent European ments preserved in All specimens within 10% of of Primobucconidae. Olson and Feduccia (1979) referred the the size of the holotype and previously referred specimens. The holotype of Parvicuculus minor (a partial tarsometatarsus) to differentialdiagnosis from the twoEuropean Primobucco species Primobucconidae, althoughHarrison (1982) disputed thisassign offered byMayr et al. (2004) is confirmedwith this larger sample. ment and instead argued for affinitieswith Cuculiformes (cuck Primobucco mcgrewi is significantly smaller than Primobucco oos and allies). Mayr and Mourer-Chauvire (2004) described a frugilegus (Table 2; compare table 1 ofMayr et al, 2004) and no ev second specimen of Parvicuculus, and concluded there is differs in proportions of the rostrum and hind limb fromPri idence for placing this taxon within either Coracii or Cuculi mobucco perneri (Mayr et al, 2004). The new sample cannot formes.Harrison (1982), in the same article arguing for the ex speak to hind limb proportions, though it confirmsa shorter ros clusion of Parvicuculus minor from Primobucconidae, assigned trum (relative to total skull length) as a diagnostic feature of a less complete proximal tarsometatarsus to the group. Though Primobucco mcgrewi relative to Primobucco perneri. We also the affinitiesof this second London Clay specimen remain un identifya more shallow medial insicure of the caudal margin of certain, the lack of the sharp, proximodistalfy elongate medial the sternum as diagnstic forPrimobucco mcgrewi relative toPri hypotarsal crest (see Harrison, 1982:fig. 4a and text), a feature mobucco perneri (condition unknown inPrimobucco frugilegus). present in stem and crown rollers, indicates this specimen is not Description and Comparison?The description focuses on el closely related to Coracii. Mayr (2005b) noted thatPrimobucco ements and morphologies of the new specimens thatwere un may nonetheless be represented in the early Eocene of England known or undescribed frompreviously reportedmaterial. Unless (pers. comm. fromM. Daniels inMayr, 2005b), though themate otherwise indicated, features noted are present in all specimens are rial forming the basis for this observation has yet to be published. preserving the element. For morphologies that observable in are a are The above-mentioned taxonomic revisions indicate there only few exemplars, the relevant specimen numbers cited. currently three valid species assignable to Primobucco, the sole Complete skulls are preserved in FMNH PA 724+758, and a genus retained in Primobucconidae (Mayr et al, 2004). Pri partial skull is preserved inFMNH PA 733. As in other Coracii, mobucco mcgrewi is the only North American species. Cracraft the skull of Primobucco mcgrewi is large relative to body size. (1971,1981) proposed a classification of rollers reflectingthe phy The beak is triangular and relatively narrow. In ventral view logenetic relationships of extant taxa that includes the higher (FMNH PA 758), the beak shape is similar to extant Coracias taxa Coracii and Coracioidea. Clarke et al. (2009), applying these and unlike the wide-beaked Eurystomus. The frontals narrow names in the context of extinct diversity, suggest that the name notably between the orbits, and a fullyossified interorbital sep Coracii be used for the clade uniting all stem and crown mem tum is present (FMNH PA 733). A nasal septum was reported bers of the roller total group (including Primobucco), and that as absent in one specimen of Primobucco mcgrewi byMayr et al. the name Coracioidea be used for the crown clade of rollers (2004), and FMNH PA 724 appears to confirm this feature. In (Coraciidae + Brachypteraciidae). We employ this taxonomy Coracioidea, a complete nasal septum ispresent (Cracraft, 1971). throughout thispaper. The Coracii affinitiesof Primobucco are As in other Coracii, the head of the lacrimal is expanded (FMNH well supported (Mayr et al, 2004; Clarke et al, 2009). Although PA 724), though the descending process is not well preserved in the three recognized species are strikinglysimilar inmorphol any specimen. The postorbital process is elongate, slender, and ogy, it should be noted that support for monophyly of Pri subcylindrical, but is damaged or obscured in all specimens. As mobucco (or Primobucconidae) was not recovered in a recent preserved in both FMNH PA 724 and FMNH PA 733, the pos analysis (Clarke et al, 2009). Primobucco species were recov torbital process contacts the jugal bar. However, this appears to ered in an unresolved polytomy at the base of Coracii. These be the result of crushing given the relatively short length of the three species differprimarily in size and proportions (Mayr et al, process and compression of the skulls. In FMNH PA 758, only the 2004). ventral tips of the processes are visible. It seems most likely that

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TABLE 1. Locality data and completeness of known Primobucco mcgrewi specimens.

Specimen Elements preserved Broken elements Locality Facies

FMNH PA 345 Partially articulated pectoral girdle, wings and ribs Yes A F-l FMNH PA 346 Disarticulated pectoral girdle wings, and ribs No K F-2 southeastern equivalent (Warfield Springs) FMNH PA 611 Partially articulated pectoral girdle, wings and ribs Yes B F-l FMNH PA 724 Articulated skull, vertebrae, pectoral girdle and wings No H F-2 FMNH PA 733 Partial skull and associated mandible Yes H F-2 FMNH PA 735 Articulated partial pectoral girdle and leftwing Yes H F-2 FMNH PA 737 Partially articulated pectoral girdle and wings No H F-2 FMNH PA 738 Articulated vertebrae, pectoral girdle and wings Yes H F-2 FMNH PA 758 Articulated skull, vertebrae, pectoral girdle and wings Yes H F-2 FMNH PA 759 Partially articulated pectoral girdle and wings, ribs No H F-2 USNM 336484 Near-complete articulated skeleton lacking left hindlimb Yes H F-2 UWGM 3299 (holotype) Articulated wing No ? F-l UWGM 12545 Partially articulated pectoral girdle, wings, vertebrae and No H F-2 ribs UWGM 14563 Partially articulated pectoral girdle and wing, vertebrae No E F-l and ribs (separate from girdle) WSGS U-93-1A Partially articulated pectoral girdle and largely Yes E F-l articulated wings, thoracic vertebrae, scattered ribs

Locality and facies definitions follow Grande and Buccheim (1994). See Figure 1 for distribution of localities. F-l deposits are from the mid-lake and F-2 are from the northeastern near-shore.

in life, the postorbital process was elongate but did not contact served inFMNH PA 758 and also bears a deep lateral depression the jugal bar. The left temporal fossa is exposed in FMNH PA or fossa. In extant Coracioidea, the thoracic vertebral centra are are a 733 and appears to have been shallow, but preservation is poor less constricted and lateral depressions absent. However, and better specimens are desirable to confirm thisobservation. large pneumatic foramen ispresent on the lateral face of the cen Palatal elements are exposed in dorsal view inFMNH PA 733 trumof the 13th transitional cervicothoracic vertebra in all rep and ventral view inFMNH PA 758. Splitting of the anterior por resentatives of extant Coracii we examined. This foramen is also tion of the skull in FMNH PA 733 reveals the rightpalatine in variably developed in the 14th vertebra in these extant taxa. dorsomedial view. The palatine has a convex posterior margin. The carina extends the entire length of the sternum (FMNH An elongate, narrow strip of bone is identified as themaxillary PA 346, FMNH PA 724). An external spine is present and well process of the rightpalatine. The substantial length of this pro developed, whereas an internal spine is absent. A large fora cess is similar to the condition in Brachypteraciidae, as well as men perforates the base of the external spine (FMNH PA 735), Momotus momota (Momotidae) and Merops ornatus (Meropi a feature shared with extant Coracii. As in Brachypteraciidae, dae). In Coraciidae, however, themaxillary process extends only the dorsal surface of the sternum inPrimobucco mcgrewi lacks a short distance before fusingwith themaxilla. The pterygoids pneumatic foramina.A single large foramen ispresent inCoraci are largely exposed inFMNH PA 758 and have a more expanded idae. Five ribs articulate with the sternum inFMNH PA 724, as anterior end than extant Coracioidea. The occipital condyle is in Coraciidae and the fossil Eocoracias brachyptera (Mayr and an very small. A moderately deep subcondylar fossa is present Mourer-Chauvire, 2000). Only four ribs contact the sternum in terior to the condyle. The basal tubera are projected, but less so Brachypteraciidae. Small pneumatic foramina perforate the ster are cau than in extant Coracioidea. Both quadrates exposed in num at the costal articulations in Coraciidae, but these appear dal view in FMNH PA758. The otic process is broad and lacks to be absent in Primobucco mcgrewi. In all specimens preserv some re the small pneumatic foramina present in clades closely ing the sternum, the caudal margin is squared, differingfrom the lated to Coracii (Alcedinidae, Meropidae, Todidae, Momotidae, more angled reconstructionpresented forPrimobucco perneri by Upupiformes; Mayr et al, 2003). A small portion of one cerato Mayr et al. (2004:fig. 1A) and resembling the condition in ex branchial is visible, but the urohyal, basihyal, and paraglossale tantCoraciidae (e.g.,Cracraft, 1971 :fig.10). Four caudal incisurae are missing. are present. Mayr et al. (2004) described themedial incisure as The mandibular Symphysis is short (~l/5 the length of the reaching nearly half the length of the sternum in Primobucco mandible). A caudal mandibular fenestra is absent in all speci mcgrewi and Primobucco perneri. However, in all specimens of mens. The articular region is exposed in lateral and ventral views. Primobucco mcgrewi preserving the complete sternum (FMNH As far as can be observed, the projection of themedial process PA 346, FMNH PA 724, FMNH PA 738, FMNH PA 758), the and absence of a retroarticular process resembles the condition medial incisure is shallow (the sternum is damaged inUSNM seen in extant Coraciidae. 336284). Posteriorly, the slendermedial trabeculae show a slight new a Because few of the specimens preserve thoracic vertebrae, expansion. The broader lateral trabeculae terminate in wide, in the vertebral formula remains uncertain. FMNH PA 758 has at verted triangle-shaped tip.The furcula isU-shaped. The rami are least 19 presacral vertebrae and is the only specimen to preserve mediolaterally flattened at the omal ends and become more cylin a small fragmentof the sacrum. Because parts of the pectoral gir drical near the Symphysis.At the Symphysisthere is a slight thick dle overlay the semi-disarticulated vertebrae, it is possible that ening, but a hypocleidium is absent. The coracoid has a proxi an additional thoracic vertebra may be hidden. Vertebrae 12-15 modistally short procoracoid process and lacks a supracoracoid bear strong ventral hypapophyses. The ventral face of the 16th nerve foramen as noted byMayr et al. (2004). The medial mar vertebra is not visible, but more posterior elements lack hypa gin is smooth,with a minute notch located at approximately the pophyses. Large depressions mark the lateral faces of the thoracic same level as the tip of the lateral process. The lateral process is vertebrae inFMNH PA 738 and FMNH PA 758, and the centra well projected and oriented anterolaterally. In dorsal view, the are a strongly constricted. The anterior-most sacral vertebra is pre articular facet for the sternum is bounded distally by strong

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FIGURE 2. Specimens of Primobucco mcgrewi from locality H. A, FMNH PA 758; B, FMNH PA 724; C, FMNH PA 735; D, FMNH PA 738. Abbreviations: ac, alular claw; ap, apex of sternal keel; br, broken bones; cmc, carpometacarpus (partially overlain by sternum); fl, ventral flange on metacarpal III (see text); It, lateral trabecula; mi, medial incisure; pap, feather papillae; pf, pneumatic foramen at base of external spine; ra, radiale; sc, scapula.

lip (FMNH PA 735), in agreement with extant Coraciidae and sites can be counted inFMNH PA 758, with a seventh possibly Brachypteraciidae. present but obscured by breakage. In FMNH PA 738, the left The dorsal tubercle of thehumerus isworn but appears to have ulnare is free and overlies the ulna; the ulnare is also exposed been caudally oriented inFMNH PA 735. A shallow depression in FMNH PA 346. The length of the crus longus of the ulnare is present on the anterior face of the ulnar condyle as noted by slightlyexceeds the lengthof the crus brevis in both specimens, Mayr et al. (2004). This feature is variably developed in extant in agreement with Primobucco perneri. Coracii and is seen in some other 'higher land ' clades (e.g., As previously noted by Mayr et al. (2004), the proximal Alcedinidae). Other details of the humerus were described by portion ofmetacarpal III bears a ventrally projected flange con some Mayr et al. (2004). Feather papillae are very weak or indistin sidered synapomorphic for Coracii. In extant Coracioidea, guishable on the ulna inmost specimens. Six secondary insertion there is a foramen perforating thisflange; however, this feature

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FIGURE 3. Skulls of Primobucco mcgrewi from locality H. A, FMNH PA 733; B, FMNH PA 724; C, FMNH PA 758. Abbreviations: cb, cera tobranchial; is, interorbital septum; mp, maxillary process of palatine; ot, otic process of quadrate; pa, palatine; po, postorbital process (broken in FMNH PA 724).

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A

FIGURE 4. Specimensof Primobucco mcgrewi. A, UWGM 14563 (localityE); B, FMNH PA 759 (localityH); C, FMNH PA 345 (localityA); D, UWGM 12545 (locality H). Abbreviations: br, broken bones; cv, cervical vertebrae; f, furcula; fi, fish vertebrae; h, humerus; im, impression of lateral trabecula of sternum; lp, lateral process of coracoid; sc, scapula; st, sternum; ul, ulna; vt, articulated cervical and thoracic vertebra. Note that portions of UWGM 14563 and FMNH PA 759 are preserved as impressions and were lost in the splitting of the slab, not by perimortem/postmortem breakage.

is unambiguously absent inmultiple specimens of Primobucco DISCUSSION mcgrewi (FMNH PA 346, FMNH PA 735, FMNH PA 758). The FBM records of Primobucco the earliest intermetacarpal process is very weak and the pisiform process mcgrewi place and constrained occurrence of stem is spike-like. In FMNH PA 758, a depression separates the phylogenetically temporally Coracii at 51.66 ? 0.09 Ma et A second stem extensor process and the pisiform process. A similarlyplaced but (Smith al, 2008). roller from the Green River Formation cannot be deeper depression occurs in Geranopterus alatus, another extinct currently to a horizon et The tar representative of Coracii (Mayr and Mourer-Chauvire, 2000). assigned specific (Clarke al, 2009). sometatarsus from to Primobucconidae Metacarpal III projects slightly beyond the distal margin of Conde-en-Brie assigned indet. et al. is also from the Eocene. metacarpal II. In all specimens where the hand is articulated, the by Mayr (2004) early a The of this fossil zones alular phalanx bears small claw. An alular claw is also present age range (MP 8-9; Schmitdt-Kittler, indicates it could be with or in Primobucco perneri (Mayr et al, 2004). Phalanx II-1 has a 1987) contemporaneous slightly older than the FBM P. more very weakly projected internal indicus process. In this respect, mcgrewi specimens. Regardless, substantial material is desirable to confirm the affinitiesof this Primobucco mcgrewi resembles Brachypteraciidae but differs tarsometatarsus to Coracii. records include from Coraciidae and the stem species Eocoracias brachyptera. Slightly younger taxa The latter taxa have an internal indicus process that is more the Messel Primobucco frugilegus, Primobucco perneri, and Eocoracias These are dated to distally projected and distinct. Phalanx II-2 is quite narrow and brachyptera. approximately 47 Ma based on a 47.8 ? 0.2 40Ar/39Ar obtained from the rod-like throughout its length,differing from themore tapering age basalt below Lake Messel et and phalanx II-2 of extant rollers. chimney (Mertz al, 2004)

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FIGURE 5. Specimensof Primobuccomcgrewi. A, FMNH PA 346 (localityK); B, FMNH PA 611 (localityB); C, WSGS U-93-1A (localityE). Abbreviations: br, broken bone; cine, carpometacarpus; ep, extensor process of carpometacarpus; f, furcula; lp, lateral process of coracoid; Is, left half of sternum; mi, medial incisure of sternum; om, omal end of scapula; pc, procoracoid process; rs, right half of sternum; sc, scapula.

accounting for sedimentation rate (Franzen, 2005). Previously ifconfirmed would be nearly contemporaneous with the FBM reported occurrences of Primobucconidae from the early Eocene Primobucco mcgrewi specimens. London Clay appear to be erroneous (see Taxonomic Remarks The 12 new specimens treated in this paper are identified above). The unpublished, privately held London Clay specimens to mid-lake or nearshore FBM deposits and can further be mentioned byMayr et al. (2005) were noted as early Eocene, and assigned to specificquarries by collection records and lithological

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comparisons (L. Grande, pers. comm.). Moreover, two of the CONCLUSIONS three of P. can now be previously reported specimens mcgrewi Extant Coraciidae hunt in environments et identified to for the first time. open (Fry al, 1992; specific quarries whereas most on the forest The FBM a rich flora and fauna Fry, 2001), Brachypteraciidae forage preserves (e.g.,MacGinitie, floor The flora and fauna of themiddle unit Feldman et Car (Langrand, 2001). 1969; al, 1981; Grande, 1984; Cushman, 1999; of the FBM are consistent with Fossil Lake valho et Conrad et Simmons et being immediately al, 2004; al, 2007; al, 2008) surrounded a low that indicates a to forested environment by humid, taxonomically diverse, paratropical tropical subtropical land forest environment sim surrounded Fossil Lake the Eocene (Buchheim, 1998; Cushman, 1999) during (MacGinite, 1969; ilar to that inferred for the fossilferous of the Grube A freshwater environment is deposits Grande, 1994; Buchheim, 1998). Messel and Lenz et Some the biota recovered from the fossiliferous (Schaal Ziegler, 1992; al, 2005). open strongly supported by areas must have been associated with local deltaic environments of themiddle unit of the more saline condi layers FBM, though near the southern of the lake atWarfield tions have at other in the of part Springs (locality may predominated periods history Given current one of the Fossil Lake K) (Buchheim, 1994a). sampling, only (Buchheim, 1994b; Grande, 1994; Buchheim, 1998). 15 Primobucco is known from those south A the distribution of referenced in this mcgrewi specimens map showing specimens eastern lake which with evidence from is in 1. Ten Primobucco deposits, along wing-shape paper presented Fig. mcgrewi specimens and diet is consistentwith a formore closed forested are from nearshore environments F-2 of Grande and preference (Table 1; environments for Primobucco. Nine of these are from the Ranch Buchheim, 1994). Thompson With the addition of 12 of Primobucco H of Grande and situated in specimens mcgrewi locality (locality Buchheim, 1994) from localities within Fossil it is clear that this the northeastern of Fossil and the 10th multiple Lake, region Lake, specimen was a of the avifauna. Prelim was collected from nearshore F-2 from the species significant component equivalent deposits tallies that this accounts for >10% of Warfield in the southern of the lake inary suggest species Springs locality part (locality FBM avian but this be a underestimate. K ofGrande and specimens, may slight Buchheim, 1994). Several FBM additional are The five Primobucco were col specimens represented by single remaining mcgrewi specimens elements that cannot be to a clade or lected frommid-lake One was assigned particular species (F-l) deposits (Fig. 1). specimen because of their but are consistent in size with recovered fromLewis Ranch site 1 A of Grande and incompleteness, (locality Primobucco rollers remain abundant in and one fromLewis Ranch site 2 B mcgrewi. Today, locally Buchheim, 1994) (locality some theirnumbers have been of Grande and Two were collected environments, although impacted Buchheim, 1994). specimens human of the forests that from State commercial site 1 E ofGrande and significantly by degradation they Wyoming (locality for or the require cavity nesting (Fry, 2001) foraging (Langrand, Buchheim, 1994). Unfortunately, holotype (UWGM 3299) Stem rollers from FBM are so far referable to cannot be to a the 2001). deposits assigned particular quarry, though lithology one abundance but low indicates it is derived fromF-l only species, suggesting appreciable deposits (L. Grande, pers. comm.) forCoracii in the FBM avifauna. Because Primobucco Primobucco are thus distributed diversity mcgrewi specimens through is a small bird with a delicate skeleton out Fossil but more common in nearshore mcgrewi relatively (as Lake, deposits. indicated bone abundance of this taxon Elements and of disarticulation are by frequent breaks), preserved pattern broadly in the FBM more reflects true abundance than increased similar in nearshore and mid-lake The most likely deposits. complete anatomical relative to other FBM all known are from nearshore F-2 preservation potential species. specimens, including skulls, One other of roller is known from the Green River The level of articulation for all Primobucco species deposits. reported Formation. Paracoracias occidentalis is much is summarized inTable 1. Broken bones are phylogenetically mcgrewi specimens closer to the roller crown clade et but the common in fromboth nearshore and mid-lake facies. (Clarke al, 2009), specimens exact of the fossil is unknown. Based on of the 15 show such Because all in provenance lithological Eight specimens breakage. it does not to have been from dividuals are at least some broken bones could comparison, however, appear missing elements, FBM The current or Pectoral elements deposits (L. Grande, pers. comm.). study represent perimortem postmortem damage. our of one of the are We found a isolated improves understanding important component disproportionately represented. single FBM avifauna. Increased taxonomic and skull and identified no isolated elements to sampling taphonomic pelvic assignable evaluation are to further resolve of Primobucco in our of 148 avian fossils from the required patterns diversity mcgrewi survey and artifacts. FBM. Because the tarsometatarsus of Primobucco is distinct identifypotential preservational from other known Green River it is these species, unlikely ACKNOWLEDGMENTS observations are biased by a failure to identify less complete specimens, though collecting bias remains a possibility. We thank Lance Grande (FMNH) and Brent Breithaupt Actualistic studies of avian taphonomy have indicated that the (UWGM) forextensive assistance and support for thisproject, in one on skull is typically of the first elements to separate from the cluding consultation specimen provenance, comments on the carcass as as access con remainder of the (Oliver and Graham, 1994; Davis and manuscript and locality data, well to specimens Briggs, 1998). The contrasting degradation pattern inP. mcgrewi sidered in this study.We thank Joel Cracraft, Paul Sweet, Peter suggests strong connections between the cervical vertebrae and Capainolo (AMNH); Peter Makovicky, Shannon Hackett, David skull, and the cervical and thoracic vertebrae, perhaps in relation Willard (FMNH); Becky Desjardins, JohnGerwin (NCSM); Ger to the relatively large heads of these birds. Three of the six ald Mayr (SMF); Storrs Olson and Mark Florence (USNM) for access reported specimens of Primobucco from the Eocene Messel to relevant extinct and extant comparative materials. This Lake deposits are complete (Mayr et al, 2004). Two specimens project was made possible by a National Science Foundation of Primobucco perneri (SMF Me 516, SMF Me 3546) preserve (USA) grant "Integrated study of an exceptional avifauna from the skull and neck in articulation with the pectoral girdle and theEocene Green River Formation: new data on avian evolution wing but lack the pelvis and hindlimb, and one otherwise com and taphonomy" (EAR 0719758; J.A.C). plete specimen of Primobucco frugilegus lacksmost parts of the LITERATURE CITED hindlimbs (SMF Me 3507). When interpretingtaphonomy in the not fossil record, it is important to consider only transport and Brodkorb, P. 1970. An Eocene Puffbird fromWyoming. Contributions to scavenging effects, but also anatomy. Recognition of a similar Geology 9:13-15. sequence of disarticulation in Primobucco specimens from Buchheim, H. P. 1994a. Paleoenvironments, lithofacies and varves of the Fossil Butte Member of the Eocene Green River South Messel provides additional support for the influence of anatomy Formation, on western Wyoming. Contributions to Geology 30:3-14. the observed degradation pattern.

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Buchheim, H. P. 1994b. Eocene Fossil Lake: a history of fluctuating salin Houde, P, and S. L. Olson. 1992. A radiation of coly-like birds from the of North Sandcoleiformes new ity; pp. 239-247 in R. Renaut and W. Last (eds.), Sedimentology Eocene America; Aves; order; pp Jr. inAvian and Geochemistry ofModern and Ancient Saline Lakes. Society for 137-160 in K. E. Campbell, (ed.), Papers Paleontology Natural Museum of Los Sedimentary Geology Special Publication 50. Honoring Pierce Brodkorb. History Ange Buchheim, H. P. 1998. A walk through time at Fossil Butte: historical ge les County, Science Series 36. O. 2001. ology of the Green River Formation at Fossil Butte National Monu Langrand, Family Brachypteraciidae (ground rollers); pp. ment; pp. 56-61 inV. L. Santucci and L. McClelland (eds.), National 378-388 in J. del Hoyo, A. Elliott, and J. Sargatal (eds.), Handbook of the Volume Mousebirds toHornbills. Park Service Paleontological Research. Geologic Resources Divi of the Birds World, 6, Lynx sion Technical Report Volume 3. NPS/NRGRD/GRDTR-98/01. Edicions, Barcelona. Buchheim, H. P, and H. P. Eugster. 1998. The Green River Formation of Lenz, O. K, V. Wilde, W. Riegel, and F. Schaarschmidt. 2005. Climate Fossil Basin, southwestern Wyoming; pp. 1-17 in J. Pitman and A. and vegetation dynamics in the pit inMessel?a reappraisal of pale Courier Carroll (eds.), Modern and Ancient Lacustrine Depositional Sys ontological data from 1980. Forschungsinstitut Senckenberg tems. Utah Geological Association Guidebook 26. 255:81-101. northwestern Col Carvalho, M. R. de, J. G. Maisey, and L. Grande. 2004. Freshwater MacGinitie, H. D. 1969. The Eocene Green flora of orado and northeastern Utah. of California Publications stingrays of the Green River Formation ofWyoming (early Eocene), University an with the description of a new genus and species and analysis of its inGeological Science 83:1-149. Bul G. 2002. On the and affinities of the phylogenetic relationships (Chondrichthyes: Myliobatiformes). Mayr, osteology phylogenetic letin of the American Museum of Natural History 284:1-136. Pseudasturidae?Lower Eocene stem-group representatives of par Clarke, J.A., D. T. Ksepka, N. A. Smith, and M. A. Norell. 2009. Com rots (Aves, Psittaciformes). Zoological Journal of the Linnean Soci new 136:715-729. bined phylogenetic analysis of a North American fossil species ety confirms widespread Eocene distribution for stem rollers (Aves, Mayr, G. 2005a. Phylogenetic affinities and composition of the early Neues Jahrbuch f?r Ge Coracii). Zoological Journal of the Linnean Society. 157:586-611. Eocene Gracilitarsidae (Aves,?Piciformes). Conrad, J. L, O. Rieppel, and L. Grande. 2007. A Green River (Eocene) ologie und Pal?ontologie, Monatshefte 2005:1-16. a The fossil record of birds in polychrotid (Squamata: Reptilia) and re-examination of iguanian Mayr, G. 2005b. Paleogene Europe. Biologi systematics. Journal of Paleontology 81:1365-1373. cal Reviews 80:515-542. Cracraft, J. 1971. The relationships and evolution of the rollers: fam Mayr, G, and S. Peters. 1998. The mousebirds (Aves: Coliiformes) from ilies Coraciidae, Brachypteraciidae, and Leptosomatidae. Auk the Middle Eocene of gr?be Messel (Hessen, Germany). Sencken 88:72-752. bergiana Lethaea 78:179-197. Cracraft, J. 1981. Toward a phylogenetic classification of the recent birds Mayr, G, and C. Mourer-Chauvire. 2000. Rollers (Aves. Coraciiformes of the world (Class Aves). Auk 98:681-714. s.s.) from the Middle Eocene of Messel (Germany) and the Upper Cushman, R. A, Jr. 1999. Vegetational history and climatic transition Eocene of the Quercy (France). Journal of Vertebrate Paleontology in an Eocene intermontane basin: plant microfossil evidence from 20:533-546. the Green River Formation, Wyoming; pp. 66-71 in V. L. Santucci Mayr, G, and C. Mourer-Chauvire. 2004. A specimen of Parvicucu and L. McClelland (eds.), National Park Service Paleontological Re lus Harrison and Walker (Aves: Parvicuculidae) from the early search. Geologic Resources Division Technical Report, Volume 4. Eocene of France. Bulletin of the British Ornithologists' Club 125: NPS/NRGRD/GRDTR-99/03. 299-304. Davis, P. G., and D. E. G. Briggs. 1998. The impact of decay and disartic Mayr, G., A. Manegold, and U. S. Johansson. 2003. Monophyletic groups and molec ulation on the preservation of fossil birds. Palaios 13:3-13. within 'higher land birds'?comparison of morphological Feduccia, A. 1973. A new Eocene zygodactyl bird. Journal of Paleontol ular data. Journal of Zoological Systematics and Evolutionary Re ogy 47:501-503. search 41:223-248. Feduccia, A, and L. D. Martin. 1976. The Eocene zygodactyl birds of Mayr, G, C. Mourer-Chauvire, and I.Weidig. 2004. Osteology and sys North America (Aves: Piciformes). Smithsonian Contributions to tematic position of the Eocene Primobucconidae (Aves, Coraci sensu Paleontology 27:101-110. iformes stricto), with first records from Europe. Journal of Sys Feldman, R. M, L. Grande, C. Birkhimer, T. J.Hannibal, and D. L. Mc tematic Palaeontology 2:1-12. Coy. 1981. Decapod fauna of the Green River Formation (Eocene) McGrew, P. O., and M. Casilliano. 1975. The geological history of Fossil ofWyoming. Journal of Paleontology 55:788-799. Butte National Monument and Fossil Basin. National Park Service Franzen, J. F. 2005. The implications of the numerical dating of theMes Occasional Paper 3:1-37. Ar sel fossil deposit (Eocene, Germany) formammalian biochronology. Mertz, D. F., F.-J. Harms, G. Gabriel, and M. Felder. 2004. in der Messel mit neven Annales de Paleontologie 91:329-335. beitstreffen Forschungsstation Grube aus 134: Fry, C. H. 2001. Family Coraciidae (rollers); pp. 342-376 in J. del Egebrissen der Messel-Forschung. Natur und Museam Hoyo, A. Elliott, and J. Sargatal (eds.), Handbook of the Birds 289-290. of theWorld, Volume 6, Mousebirds to Hornbills. Lynx Edicions, Oliver, J. S, and R. W. Graham. 1994. A catastrophic kill on ice-trapped Barcelona. coots: time-averaged versus scavenger-specific disarticulation pat Fry, C. H, K. Fry, and A. Harris. 1992. Kingfishers, Bee-eaters and terns. Paleobiology 20:229-244. occurrence Rollers. Princeton University Press, Princeton, New Jersey. Olson, S. L, and A. Feduccia. 1979. An Old World of the a Grande, L. 1984. Paleontology of the Green River Formation, with Eocene avian family Primobucconidae. Proceedings of the Biologi review of the fish fauna. Geological Survey of Wyoming Bulletin cal Society ofWashington 32:494-497. 63:1-333. Schaal, S, and W. Ziegler. 1992. Messel?An Insight into the History of Grande, L. 1994. Studies of paleoenvironments and historical biogeog Life and of the Earth. Claredon Press, Oxford. ta raphy in the Fossil Butte and Laney Members of the Green River Schmidt-Kittler, N. 1987. European reference levels and correlation Formation. Contributions to Geology 30:15-52. bles. M?nchner Geowissenschaftliche Abhandlungen, Reihe A, Ge Grande, L. 2001. An updated review of the fish fauna from the Green ologie und Pal?ontologie 10:13-19. River Formation, the world's most productive lagerstatten; pp. 1-38 Simmons, N. B, K. L. Seymour, J.Habersetzer, and G. F. Gunnell. 2008. inG. Gunnell (ed.), Eocene Vertebrates: Unusual Occurrences and Primitive Early Eocene bat from Wyoming and the evolution of Rarely Sampled Habitats. Plenum Publishing, New York. flight and echolocation. Nature 451:818-821. Grande, L, and H. P. Buchheim. 1994. Paleontological and sedimento Smith, M. E, A. R. Carroll, and B. S. Singer 2008. Synoptic reconstruc a logical variation in Early Eocene Fossil Lake. Contributions to Ge tion of major ancient lake system: Eocene Green River Forma ology 30:33-56. tion, western United States. Geological Society of America Bulletin Harrison, C. J.0.1982. Cuculiform, piciform and passeriform birds in the 120:54-84. lower Eocene of England. Tertiary Research 4:71-81. Wetmore A., and W. W. Miller. 1926. The revised classification for the Houde, P., and S. Olson. 1989. Small arboreal non-passerine birds from fourth edition of the AOU Check-list. Auk 43:337-346. the early Tertiary of western North America; pp. 2030-2036 in H. Ouellet (ed.), Acta XIX Congressus Internationalis Ornithologici. Submitted October March University of Ottawa Press, Ottawa, Ontario. 1, 2008; accepted 14,2009.

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