Botany
Fossil species of Boehmerieae Gaudich. (Urticaceae) in Dominican and Mexican amber: A new genus (Ekrixanthera) and two new species with anemophilous pollination by explosive pollen release, and possible lepidopteran herbivory
Journal: Botany
Manuscript ID cjb-2016-0006.R2
Manuscript Type: Article Date Submitted by the Author: 04-May-2016Draft Complete List of Authors: Poinar, Jr., George; Oregon State University, Department of Integrative Biology Kevan, Peter; Environmental Biology Jackes, Betsy; James Cook University
palaeobotany, anemophily, Ekrixanthera hispaniolae, Ekrixanthera ehecatli, Keyword: paleoecology
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Fossil species in Boehmerieae Gaudich. (Urticaceae) in Dominican
and Mexican amber: A new genus ( Ekrixanthera ) and two new
species with anemophilous pollination by explosive pollen release,
and possible lepidopteran herbivory
GEORGE POINAR, JR. 1 PETER G. KEVAN 2 AND BETSY R. JACKES 3
1Department of Integrative Biology, Oregon State University, Corvallis, Oregon, 97331 USA
2School of Environmental Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada 3College of Marine and Environmental DraftSciences, James Cook University, Townsville, QLD 4811, Australia
Corresponding Author: Peter G. Kevan [email protected]
Received; revised; accepted for publication
Running title: Fossil species of Boehmerieae (Ekrixanthera gen. nov.)
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ABSTRACT
The first fossil flowers of Neotropical Urticaceae (Boehmerieae) are described from the
Dominican Republic and Mexico as belonging to a new genus, Ekrixanthera . Ekrixanthera hispaniolae sp. nov. from Dominican amber has pentamerous staminate flowers on short pedicels with a pilose pistillode and heteromorphic pilose tepals, two are clavate and three linear. Ekrixanthera ehecatli sp. nov. has pentamerous staminate flowers lacking pedicels, a pistillode with greatly reduced pilosity, glabrous and heteromorphic tepals with two linear and three wedge shaped with truncate tips. The presence or absence of a pedicel, heterotrophic condition of the tepals and presence or absence of pilosity of the pistillode and tepals separate the two species. Those characters, together with the pentamerous flowers separate both fossil species from extant genera. The floral Draftstructures indicate explosive pollen release and pollination by wind (anemophily). Pistillate flowers have not been found for this usually dioecious tribe. Lepidopteran herbivory is suggested by a damaged stipule in one specimen and a nymphalid butterfly ( Vanessa like) caterpillar that may have used Ekrixanthera as a food plant is illustrated. The fossils establish an early lineage of Boehmerieae with characteristic explosive pollen release and perhaps associated herbivorous insects in the West Indies and North America during the mid Tertiary.
Keywords: palaeobotany, paleoecology, anemophily, Ekrixanthera hispaniolae , Ekrixanthera ehacatli
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INTRODUCTION
Amber is a wonderful medium for preserving delicate structures like flowers and has provided
evidence of various plant lineages dating back to the Early mid Cretaceous. New World ambers
from the Dominican Republic and Mexico have provided rare glimpses into the flora that existed
in the West Indies during the mid Tertiary. Genera from the following families of angiosperms
have been described from this New World amber: Poaceae (Poinar and Judziewicz 2005; Poinar
and Columbus 2012), Arecaceae (Poinar 2002a; 2002b), Chrysobalanaceae (Poinar et al. 2008a;
corrected by Chambers and Poinar 2010), Lauraceae (Chambers et al. 2011a; 2012), Meliaceae
(Chambers et al. 2011b; Chambers and Poinar 2012), Burseraceae (Chambers and Poinar 2013),
Myristicaceae (Poinar and Steeves 2013), Rhamnaceae (Chambers and Poinar 2014a),
Ticodendraceae (Chambers and Poinar Draft2014b), Fabaceae (Poinar 1991; Poinar and Brown 2002)
and possibly Moraceae (Poinar et al. 2008b). The Dominican amber forest was characterized by
Poinar and Poinar (1999) based on both animal and plant fossils.
The Urticaceae is a large family with over 45 genera and some 2000 species (Friis 1989;
Wu et al. 2015). The family has a poor fossil record of flowers, with only one definite flower
(Forskohleanthium nudum Conwentz) having been described in Baltic amber (Conwentz 1886).
The present work describes two congeneric species that share characters with other
Boehmerieae, such as Boehmeria, but have characters that prevent assignment to an extant
genus. One species is described from Dominican and the other from Mexican amber. They
represent the first fossil flowers of Neotropical Urticaceae.
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MATERIAL AND METHODS
PROVENANCES
The Dominican amber fossils originated from amber mines in the northern mountain range
(Cordillera Septentrional) of the Dominican Republic between Puerto Plata and Santiago.
Amber from mines in this region was produced by Hymenaea protera Poinar (1991) (Fabaceae).
Dating of Dominican amber is still controversial, with the youngest proposed age of 20 15 mya based on Foraminifera (Iturralde Vincent and MacPhee 1996) and the oldest of 45 30 mya based on coccoliths (Cepek in Schlee 1990). These are considered minimum dates as they are based on microfossils in the strata containing the amber. Most of the amber was secondarily deposited in turbiditic sandstones of the Upper EoceneDraft to Lower Miocene Mamey Group (Draper et al. 1994). Dilcher et al. (1992) stated that “...the amber clasts, from all physical characteristics, were already matured amber at the time of re deposition into marine basins. Therefore, the age of the amber is greater than Miocene and quite likely is as early as late Eocene”. The issue is further complicated by the discovery of Early Oligocene amber in Puerto Rico and Maastrichtian
Paleocene amber in Jamaica (Iturralde Vinent 2001) showing that amber from a range of deposits occurs in the Greater Antilles.
The Mexican amber fossils originated from amber mines in the northern mountain ranges or Chiapas Highlands of the Simojovel area in Chiapas, Mexico. Amber from Chiapas, which was produced by Hymenaea mexicana (Fabaceae) (Poinar and Brown 2002), occurs in lignitic beds among sequences of primarily marine calcareous sandstones and silt. The amber is associated with Balumtun Sandstone of Early Miocene and the La Quinta Formation of the Late
Oligocene with radiometric ages from 22.5 to 26 million years (Berggren and Van Couvering
1974). Because the amber was secondarily deposited in these marine formations, it may be
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somewhat older than the above dates.
METHODS
Observations and photographs were made with a Nikon SMZ 10 R stereoscopic microscope and
Nikon Optiphot compound microscope with magnifications up to 600 X. Helicon Focus Pro X64
was used to stack photos for better clarity and depth of field.
RESULTS
Three separate pieces of Dominican amber contain fossil representatives ascribed to the tribe
Boehmerieae but not to an extant genus. Dominican amber piece Sd 9 95ADraft contains a single staminate flower (Figs. 1 3). Dominican amber piece Sd 9 95B contains two staminate flowers, one with the tepals and
stamens beginning to unroll and another with the tepals and stamens outstretched (Fig. 4). The
same piece of amber also contains a developing fruit but not on the same structure (Fig. 5) and
an insect damaged stipule (Fig. 6) with evidence of putative cystoliths (Fig. 7). Two conjoined
staminate flowers with short pedicels in lateral view (specimen Sd 9 95C) provide indication of
the structure of the inflorescence (Fig. 8).
The Mexican amber piece (Sd 9 96) contains two staminate flowers, one of which is
completely opened (Figs. 9, 10) and another that has the stamens bent back, one of which was
releasing pollen (Fig. 11). We found no evidence of female reproductive structures.
TAXONOMIC PLACEMENT AND DESCRIPTIONS
The specimens we describe (below) belong to species in the tribe Boehmerieae, a large
tribe which, as presently considered, comprises about 20 genera with limits that often are not
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satisfactory. The presence of the pistillode in the staminate flowers of both species we describe indicates that neither can be placed in the tribe Urticeae. With the characters that are preserved in the fossils we describe, we note five similar extant genera in Boehmerieae. We rule out assignment to Nothocnide, Cypholophus and Oreocnide on the basis of stipule forms. Species in the genera Pouzolzia and Boehmeria share greater similarities with the fossils we describe with pentamerous male flowers. In Pouzolzia they are usually vaulted at the apex, at least in Javanese species (Backer and Bakhuizen van den Brink 1965). Staminate flowers of extant species of
Boehmeria are regular (actinomorphic) and most are reported to be tetramerous (Friis 1989), which would separate them from those of the fossils we describe. A persistent filamentous style on the developing fruit is expected for Boehmeria but not necessarily for Pouzolzia (Wilmot
Dear et al. 2009). Even so, the two generaDraft are difficult to distinguish morphologically (Wilmot
Dear et al. 2009). On the basis of morphological and molecular data, members of Boehmeria and Pouzolzia have been assigned to three or two subclades respectively, suggesting polyphyletic origins of both genera (Hadiah et al. 2008; Conn and Hadiah 2009; Wu et al. 2015). The morphological characters defining both genera may be plesiomorphic within at least one of the clades. Because we cannot assign the fossil specimens we describe unambiguously to an extant genus, we propose a new genus, Ekrixanthera , within the tribe
Boehmerieae.
Etymology: The new generic epithet is descriptive of the explosive release of the pollen from the anthers: In Greek Εκρηχικός means explosive and ανθήρας means anther.
Urticaceae: Boehmerieae
Ekrixanthera
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Staminate flowers pentamerous, pistillode present: differs from Pouzolzia by the flowers being
pentamerous and from Boehmeria by the pentamerous flowers rarely found in Boehmeria and the
absence of a persistent filamentous style. The stipule is apiculate.
Ekrixanthera hispaniolae n.sp. (Figs. 1 8)
Description
Specimen in Sd-9-95A (Figs. 1 3): Staminate flowers pentamerous with very short pedicel and
hairy perianth. Flower diameter 4.4 mm; tepals heteromorphic, 3 linear, 2 clawed; length tepals,
1.7 (1.5 2.1) mm; width at base, 0.5 (0.4 0.6) mm; width at tip, 0.8 (0.4 1.4) mm; stamens
opposite tepals, filament length, 1.4 (1.2 1.6) mm; anthers two locular, split longitudinally,
length, 1.1 (0.8 1.3) mm; pistillode pilose.
Draft
Specimen in Sd-9-95B (Figs. 4 7): Stipule narrowly ovate, 8.3 mm long, base cordate, tip
pointed, with putative cystoliths present (Fig. 7). Staminate flowers pentamerous with very short
pedicel and hairy perianth. Flower diameter 4.1 mm; tepals heteromorphic, 3 linear, 2 clawed;
length tepals, 1.6 (1.4 1.9) mm; width at base 0.5 (0.4 0.6); width at tip, 0.9 (0.5 1.5); stamens
opposite tepals; filament length, 1.5 (1.4 1.6); anthers two locular, split longitudinally, length,
0.9 (0.8 1.1) mm; pistillode pilose; achene glabrous, stigma absent, surrounded by 5 unequal
perianth lobes.
Specimens in Sd-9-95C (Fig. 8). Two staminate pentamerous flowers. Although the floral parts
are coiled and difficult to measure, they appear to have the same features indicated above in
specimens Sd 9 95A and Sd 9 95B. A lateral view shows the short pedicels measuring 0.2 mm
in length (Fig. 8).
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Types: Holotype (accession # Sd 9 95A) (Figs. 1 3) and Paratypes (Sd 9 95B and Sd 9 95C)
(Figs. 4 8) deposited in the Poinar amber collection maintained at Oregon State University,
Corvallis, Oregon.
Type locality: Amber mine in the northern mountain ranges (Cordillera Septentrional) of the
Dominican Republic.
Etymology: The specific name reflects the country of origin of the fossil.
Urticaceae: Boehmerieae
Ekrixanthera ehecatli n.sp. (Figs. 9 11)
Description
Specimen in Sd-9-96: Two pentamerousDraft glabrous staminate flowers lacking pedicels; one open and one partially closed. Measurements for open flower: flower diameter, 3.6 mm; tepals heteromorphic, 2 linear and 3 wedge shaped; length tepals, 1.2 (0.9 1.3) mm; width at base, 0.5
(0.4 0.7) mm; width at tip, 0.9 (0.5 0.9); stamens opposite tepals, filament length, 0.8 (0.7 0.9) mm; anthers two locular, split longitudinally, length, 0.8 (0.7 0.9) mm; pistillode reduced to a few hairs.
Types: Holotype deposited in the Poinar amber collection (accession # Sd 9 96) maintained at
Oregon State University, Corvallis, Oregon.
Type locality: Amber mine in the northern mountain ranges of the Simojovel area in Chiapas,
Mexico.
Etymology: The specific name reflects the evidence for anemophily (Figure 11) and makes reference to the Aztec god of the wind, Ehécatl, also associated with other Náhuatl cultures, including the Maya.
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Comments: E. ehecatli shares the character of heteromorphic tepals with E. hispaniolae .
However in E. ehecatli , only two tepals are linear, while the other three are wedge shaped rather
than clavate as in E. hispaniolae . The staminate flowers of E. hispaniolae are pubescent but
those of E. ehecatli are glabrous. Pedicels are absent in E. ehecatli but present in E. hispaniolae .
DISCUSSION
The only previous confirmed fossil flower of the Urticaceae is the single Baltic amber
Forskohleanthium nudum Conwentz (Conwentz 1886). The present fossils are the first New
World flowers of the Urticaceae. Actinomorphic (regular) flowers is a basic character of the
Utricaceae (Berg 2004) and it is curiousDraft that in the mid Tertiary, representatives of the family
existed with heteromorphic flowers (the tepals and sexual forms). It is interesting that Bechtel
(1921) suggested that flowers of Urticales originated from flowers with two whorls of perianth
parts; the heteromorphic tepals in the fossils support that idea. The glabrous condition of the
tepals of E. ehecatli reveals what appears to be a basal whorl of two linear tepals under a
separate whorl of wedge shaped tepals when viewed from below (Fig. 10).
Explosive pollen release is a characteristic of the family (see Montoya Pfeiffer et al.
2016) and is demonstrated in the flower of E. ehecatli that has a burst of pollen adjacent to the
anther. Such explosive “bursts” propel the pollen into the air to be conveyed by wind and
atmospheric turbulence to receptive pistillate flowers on the same (monoecy) or different
(required for dioecy) plants, thus permitting pollination. Details of anemophily in Boehmeria
caudata Sw., and other plants with explosively released pollen in Urticaceae and other families
are provided in the preceding paper (Montoya Pfeiffer et al. 2016). Unfortunately, we cannot
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comment on the breeding system (monoecy vs. dioecy) in the fossil plants we describe because pistillate flowers are poorly represented and in the single example (Fig. 5) of both floral sexes being present in the same sample of amber, they are not structurally unified.
Several insects were associated with the flowers of E. hispaniolae . A small and incomplete caterpillar was near the stipule that showed evidence of insect damage (Fig. 12). The fossil shown in Fig. 12 is morphologically very similar to a previously collected caterpillar in
Dominican amber that has been identified as a prototypic extinct ancestor of the Nymphalidae
Pycina Vanessa linkage that is considered to belong to the Urticaceae feeding tribe Nymphalini
(Fig. 13). Today caterpillars of Vanessa Fabricius and the related Hypanartia Hübner are the only butterflies that feed on Urticaceae in Hispaniola (Hammond and Poinar 1998).
Several adult gall midges (Diptera:Draft Cecidomyiidae) were adjacent to the female flower.
Gall midges are known to develop in stem galls of Boehmeria in North America (Gagné 1989). It is possible that the fossil gall midges had a similar relationship with E. hispaniolae . An ant belonging to the subfamily Dolichoderinae was adjacent to one of the male flowers (see also antenna in Figure 4).
ACKNOWLEDGEMENTS
We thank the students (Montoya Pfieffer et al. 2016) on the International Pollination Course at
Intervales State Park, São Paulo, Brazil in December 2014 for being the catalysts for this submission. It was through their study on Boehmeria caudata followed by the suggestion of
Peter Bernhard of St. Louis University and friendship between BJ and PGK that we came together. GP thanks Cesare Baroni Urbani for determination of the ant in Sd 9 95B. PGK thanks the Canadian Natural Sciences and Engineering Research Council for help in funding preparation and publication of this paper.
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REFERENCES
Backer, C. A. and Bakhuizen van den Brink, C. R.1965. Flora of Java. Volume II: p. 46. P.
Noordhoff , Groningen, Netherlands.
Bechtel, A. R. 1921. The floral anatomy of the Urticales. American Journal of Botany 8: 386
410.
Berg, C. C. 2004. Urticaceae (Nettle Family). pp. 384 385. In: Smith N, Mori SA, Henderson A,
Stevenson, D. W., and Heald, S. V., eds. Plants of the Neotropics. Princeton University Press,
Princeton.
Berggren, W. A., and Van Couvering, J. A. H. 1974. The late Neogene. Palaeogeography
Palaeoclimatology, Palaeoecology 16 :1–216. Chambers, K. L. and Poinar Jr., G. O. 2010.Draft The Dominican amber fossil Lasiambix (Fabaceae: Caesalpinioideae) is a Licania (Chrysobalanaceae). Journal of the Botanical Research Institute of
Texas 4:217 218.
Chambers, K. L., Poinar Jr., G. O. and Brown A. E. 2011a. A fossil flower of Persea (Lauraceae)
in Tertiary Dominican amber. Journal of the Botanical Research Institute of Texas 5:457 462.
Chambers, K. L, Poinar Jr., G. O., and Brown, A. E. 2011b. Two fossil flowers of Trichilia
(Meliaceae) in Dominican amber. Journal of the Botanical Research Institute of Texas 5:463
468.
Chambers, K. L., and Poinar Jr., G. O. 2012. A Mid Tertiary fossil flower of Swietenia
(Meliaceae) in Dominican amber. Journal of the Botanical Research Institute of Texas 6:123
127.
Chambers, K. L., Poinar Jr., G. O., and Chanderbali, A. S. 2012. Treptostemon (Lauraceae), a
new genus of fossil flower from Mid Tertiary Dominican amber. Journal of the Botanical
Research Institute of Texas 6:551 556.
https://mc06.manuscriptcentral.com/botany-pubs Botany Page 12 of 31
Chambers, K. L., and Poinar Jr., G. O. 2013. A fossil flower of the genus Protium (Burseraceae) in Mid Tertiary amber from the Dominican Republic. Journal of the Botanical Research Institute of Texas 7:367 373.
Chambers, K. L., and Poinar Jr., G. O. 2014a. Distigouania irregularis (Rhamnaceae) gen. et sp. nov. in Mid Tertiary amber from the Dominican Republic. Journal of the Botanical Research
Institute of Texas 8: 551 557.
Chambers, K. L. and Poinar Jr., G. O. 2014b. Ticodendron palaios sp. nov. (Ticodendraceae), a
Mid Tertiary fossil flower in Dominican amber. Journal of the Botanical Research Institute of
Texas 8: 559 564.
Conn, B. J., and Hadiah, J. T. 2009. Nomenclature of the tribes within the Urticaeae. Kew
Bulletin 64(2): 349 – 352. Draft
Conwentz, H. 1886. Die Flora des Bernstein. Vol. 2. Wilhelm Engelmann Verlag, Leipzig.
Dilcher, D. L., Herendeen, P. S. and Hueber, F. 1992. Fossil Acacia flowers with attached anther glands from Dominican Republic amber. p. 33 42. In: Herendeen, P. S., and Dilcher, D.
L., eds. Advances in legume systematics: 4. The fossil record. The Royal Botanical Gardens;
Kew, England. 326 pp.
Draper, G., Mann, P., and Lewis, J. F. 1994. Hispaniola. In: Donovan S, Jackson TA, eds.
Caribbean geology: an introduction. The University of the West Indies Publishers’ Association.
Kingston, Jamaica. pp. 129–150.
Friis, I. 1989. Review of Urticaceae. In: Crane PR., Blackmore S, eds. Evolution, systematics and fossil history of the Hammelidae ‘Higher’ Hamamelidae. Volume 2:
285 308. Clarendon Press, Oxford.
Gagné, R. J. 1989. The plant-feeding gall midges of North America. Cornell University
https://mc06.manuscriptcentral.com/botany-pubs Page 13 of 31 Botany
Press, Ithaca, 356 pp..
Hadiah, J.T., Conn, B. J.and Quinn, C. J. 2008. Infra-familial phylogeny of Urticaceae, using
chloroplast sequence data. Australasian Systematic Botany 21 : 375 – 385
Hammond, P. C., and Poinar Jr., G. O. 1998. A larval brush footed butterfly (Lepidoptera:
Nymphalidae) in Dominican amber, with a summary of fossil Nymphalidae.
Entomologica Scandanavica 29 : 275 279
Iturralde Vinent, M. A. 2001. Geology of the amber bearing deposits of the Greater Antilles.
Caribbean Journal of Science 37 : 141 167.
Iturralde Vinent, M. A., and MacPhee, R. D. E. 1996. Age and Paleogeographic
origin of Dominican amber. Science 273 : 1850–1852.
Montoya Pfeiffer, P. M., Kevan, P. G., DraftGonzález Chaves, A., Pereira Queiroz, E., and Dec, E.
2016 Explosive pollen release, stigma receptivity and pollen dispersal pattern of
Boehmeria caudata Sw. (Urticaceae) in a Brazilian rain forest. Botany (in press)
Poinar Jr., G. O. 1991. Hymenaea protera sp. n. (Leguminosae: Caesalpinioideae) from
Dominican amber has African affinities. Experientia 47 :1075 1082.
Poinar Jr., G. O. and Poinar, R. 1999. The amber forest. Princeton University Press, Princeton,
New Jersey, U.S.A.
Poinar Jr., G. O. 2002a. Fossil palm flowers in Dominican and Mexican amber. Botanical
Journal of the Linnean Society 138 :57 61.
Poinar Jr., G. O. 2002b. Fossil palm flowers in Dominican and Baltic amber. Botanical Journal
of the Linnean Society 139 :361 367.
https://mc06.manuscriptcentral.com/botany-pubs Botany Page 14 of 31
Poinar Jr., G. O., and Brown, A. E. 2002. Hymenaea mexicana sp. nov. (Leguminosae:
Caesalpinioideae) from Mexican amber indicates Old World connections. Botanical Journal of the Linnean Society 139 :125 132.
Poinar Jr., G. O., and Judziewicz, E. J. 2005. Pharus primuncinatus (Poaceae: Pharoideae:
Phareae) from Dominican amber. Sida 21 :2095 2103.
Poinar Jr., G. O., Chambers, K. L., and Brown, A. E. 2008a. Lasiambix dominicensis gen. and sp. nov., a eudicot flower in Dominican amber showing affinities with Fabaceae subfamily
Caesalpinioideae. Journal of the Botanical Research Institute of Texas 2:463 471.
Poinar Jr., G. O., Chambers, K. L., and Brown, A. E. 2008b. Trochanthera lepidota gen. and sp. nov., a fossil angiosperm inflorescence in Dominican amber. Journal of the Botanical Research
Institute of Texas 2: 1167 1173. Draft
Poinar Jr., G. O., and Columbus, J. T. 2012. Alarista succina gen. et sp. nov. (Poaceae:
Bambusoideae) in Dominican amber. Historical Biology 25 :1 6.
Poinar Jr., G. O., and Steeves, T. 2013. Virola dominicana sp. nov. (Myristicaceae) from
Dominican amber. Botany 91 :530 534.
Schlee, D. 1990. Das Bernstein Kabinett. Stuttgarter Beitrage Naturkunde Ser. C 28 . 100 pp.
Wilmot Dear, C. M., Acharya, N., Kravtsova, T. I., and Friis, I. 2009. Pouzolzia rugulosa transferred from Boehmeria , and the distinction between Boehmeria and Pouzolzia (Urticaceae).
Edinburgh Journal of Botany 66 (1): 51 – 64.
Wu, Z Y., Milne, R. I., Chen, C J., Liu, J., Wang, H., and Li, D Z . 2015. Ancestral state reconstruction reveals rampant homoplasy of diagnostic morphological characters in Urticaceae, conflicting with current classification schemes. PLoS ONE 10 (11): e0141821. doi:10.1371/journal.pone.0141821
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Figure Captions
Figure 1. Top view of staminate flower of Ekrixanthera hispaniolae n. sp. in Dominican amber.
Specimen Sd 9 95A. Scale bar = 1.0 mm.
Figure 2. Detail of underside of staminate flower of Ekrixanthera hispaniolae n. sp. in
Dominican amber. Specimen Sd 9 95A. Scale bar = 0.4 mm.
Figure 3. Detail of center of staminate flower of Ekrixanthera hispaniolae n. sp. in Dominican amber showing pilose pistillode. Specimen Sd 9 95A. Scale bar = 0.3 mm.
Figure 4. .Top view of second staminateDraft flower of Ekrixanthera hispaniolae n. sp. in Dominican amber. Ant’s (Hymenoptera: Formicidae: subfamily Dolichoderinae) antenna is preserved with the flower (bottom of picture). Specimen Sd 9 95B. Scale bar = 0.6 mm.
Figure 5. Developing fruit of Ekrixanthera hispaniolae n. sp. in Dominican amber. Note the lack of persistent style. Specimen Sd 9 95B. Scale bar = 1.9 mm.
Figure 6. Stipule of Ekrixanthera hispaniolae n. sp. in Dominican amber. Note damage (arrow), probably from feeding caterpillar preserved in the same piece of amber (Figure 12). Specimen
Sd 9 95B. Scale bar =1.3mm.
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Figure 7. Leaf upper surface of Ekrixanthera hispaniolae n. sp. in Dominican amber showing
putative cystoliths (arrow). Specimen Sd 9 95B. Scale bar = 62 µm.
Figure 8. Lateral view of two staminate flowers of Ekrixanthera hispaniolae n. sp. in Dominican
amber. Specimen Sd 9 95C. Arrows indicate short pedicels. Scale bar = 1.0 mm.
Figure 9. Top view of staminate flower of Ekrixanthera ehecatli n. sp. in Mexican amber. The
pistillode is reduced to a few hairs. Specimen Sd 9 96. Scale bar = 0.8 mm.
Figure 10. Underside of staminate flower of Ekrixanthera ehecatli n. sp. in Mexican amber.
Specimen Sd 9 96. Scale bar = 0.7 mm.Draft
Figure 11. Freeze frame fossilized release of pollen from an anther of Ekrixanthera ehecatli n.
sp. in Mexican amber. Specimen Sd 9 96B. For discussion on explosive release of pollen from
Boehmerieae, see Montoya Pfeiffer et al. (2016) and associated video clip. Scale bar = 0.3 mm.
Figure 12. A caterpillar associated directly with the damaged stipule in Figure 6. The specimen is
too incomplete to assign it to Nymphalidae. Specimen Sd 9 95B from the Poinar collection
contains both the stipule and this caterpillar. Scale bar = 0.6mm.
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Figure 13. A nymphalid butterfly caterpillar identified as a prototypic extinct ancestor of the
Nymphalidae Pycina Vanessa linkage that is considered to belong to the Urticaceae feeding tribe
Nymphalini ( Specimen L-3-36 from the Poinar collection). The fossil shown in Figure 12, although not so well preserved, is similar enough to be worth note. Caterpillars of Vanessa
Fabricius and the related Hypanartia Hübner are the only butterflies that feed on Urticaceae in
Hispaniola today (Hammond and Poinar, 1998). Scale bar = 2.3 mm.
Draft
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