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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-2016

Complete List of Authors: Poinar, Jr., George; Oregon State University, Department of Integrative Biology Kevan, Peter; Environmental Biology Jackes, Betsy; James Cook University

Keyword: palaeobotany, anemophily, Ekrixanthera hispaniolae, Ekrixanthera ehecatli, 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 Sciences, James Cook University, Townsville, QLD 4811,

Australia

Corresponding Author: Peter G. Kevan pkevan@uoguelph.ca

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 structures 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 2014b), 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 Eocene 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-9-95A 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 genera 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.

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 pentamerous 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 curious 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: 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. 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.

Page 11 of 31

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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.

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

Page 12 of 31

https://mc06.manuscriptcentral.com/botany-pubs

Botany

Draft

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., González-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.

Page 13 of 31

https://mc06.manuscriptcentral.com/botany-pubs

Botany

Draft

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.

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 staminate 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.

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.

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