University of Florida Thesis Or Dissertation

Home , Culebra Formation, Oxydactylus, Paratylopus, Protoceras

SYSTEMATICS, BIOSTRATIGRAPHY, AND PALEOBIOGEOGRAPHY OF EARLY MIOCENE ARTIODACTYLS FROM THE PANAMA CANAL, PANAMA, CENTRAL AMERICA

ALDO FERNANDO RINCÓN

A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR IN GEOLOGY UNIVERSITY OF FLORIDA

2016

To my dear grandmother…

ACKNOWLEDGMENTS

I thank Carlos A. Jaramillo at STRI and Camilo Montes at Universidad de Los

Andes for all these years of support and advice; to my advisor (Jonathan I. Bloch) for everything he has done for my professional development; to the additional members of my Research Committee (Bruce J. MacFadden, David A. Foster, Richard C. Hulbert Jr., and David W. Steadman) for help with anatomical terminology, taxonomic nomenclature, and academic support. Special thanks to Richard Hulbert Jr., David

Steadman, and Jason R. Bourque for their moral support during the preparation of the final document and, in general, during my attendance to graduate school. Jason R.

Bourque, Rachell Narducci, and Dawn Mitchell at FLMNH, who prepared the specimens in the laboratory. Sandra Suarez, Maria C. Vallejo, and Federico Moreno (STRI); Jorge

Moreno-Bernal, Cristina Byrd, Alan Bouché, Silvia Ascari, Katy. Cummings, Aaron. R.

Wood, and Chris Ward (PCP-PIRE) who helped in the collection of the specimens. I thank the Panama Canal Authority (ACP) for access to relevant fossil sites. I specially thank to Pamela Haines, John Jaeger and Raymond Russo in the Department of

Geological Sciences at the University of Florida for all their help during the Graduate

Program.

This research was supported by UF Research Opportunity Grant; the U.S.

National Science Foundation Partnerships in International Research and Education grant 0966884 (OISE, EAR, DRL), EAR 0824299, and EAR 0418042; funds from the

Florida Museum of Natural History; University of Florida, Department of Geology; STRI-

Tupper Paleontological Fund; STRI-Panama Canal Authority Fund; and Ricardo Perez

Toyota, Panama.

TABLE OF CONTENTS

page

ACKNOWLEDGMENTS ...... 4

LIST OF TABLES ...... 8

LIST OF FIGURES ...... 10

ABSTRACT ...... 13

CHAPTER

1 INTRODUCTION ...... 15

Conventions ...... 21 Institutional Abbreviations ...... 22 Geological Setting ...... 23 Biostratigraphy of Early Miocene Terrestrial Mammals from Panama ...... 27

2 EARLY MIOCENE FOSSIL PROTOCERATIDS (PROTOCERATINAE) FROM PANAMA ...... 32

Systematic Paleontology ...... 37 Paratoceras aff. P. tedfordi ...... 39 Description ...... 39 Discussion and Comparisons ...... 42 Paratoceras orarius sp. nov...... 43 Description ...... 44 Discussion and Comparisons ...... 46 Paratoceras coatesi sp. nov...... 47 Description ...... 49 Discussion and Comparisons ...... 56 Phylogenetic Analysis ...... 58 Discussion ...... 60

3 EARLY MIOCENE FLORIDATRAGULINE CAMELS FROM PANAMA ...... 81

Systematic Paleontology ...... 89 Aguascalientia panamaensis Rincón et al., 2012 ...... 90 Description ...... 92 Discussion and Comparisons ...... 94 Floridatragulus sp. nov...... 96 Description ...... 97 Discussion and Comparisons ...... 103 Floridatragulinae, gen. nov...... 107

Floridatragulinae gen. et. sp. nov...... 108 Description ...... 109 Comparisons ...... 116 Discussion...... 120 Phylogenetic Analysis ...... 122 Late Oligocene to Early Miocene Higher Camelid Paleobiogeography in Southern North America ...... 126 Discussion ...... 129

4 EARLY MIOCENE TAYASSUIDS FROM PANAMA ...... 152

Systematic Paleontology ...... 164 Hesperhyinae, gen. et. sp. nov...... 164 Hesperhyinae n. gen. A & sp. A...... 165 Description ...... 166 Comparisons ...... 171 Hesperhyinae n. gen. A & sp. B ...... 173 Description ...... 174 Comparisons ...... 180 Floridachoerus White, 1941 ...... 184 Description ...... 185 Discussion...... 186 Hesperhyinae n. gen. B...... 186 Hesperhyinae n. gen. B & sp. A ...... 187 Description ...... 188 Comparisons ...... 191 Phylogenetic Analysis ...... 194 Discussion ...... 197

5 ARTIODACTYL FAUNAL COMPOSITION AND PALEOECOLOGY ...... 218

6 CONCLUSIONS ...... 243

APPENDIX

A DENTAL MEASUREMENTS OF PROTOCERATINES FROM THE EARLY MIOCENE FROM PANAMA ...... 251

B DENTAL CHARACTERS USED IN THE PHYLOGENETIC ANALYSIS OF PROTOCERATINAE (CHAPTER 2). ALL CHARACTERS ARE TREATED AS UNORDERED...... 257

C CHARACTER-TAXON MATRIX USED IN PHYLOGENETIC ANALYSES OF PROTOCERATIDAE (CHAPTER 2). SEE APPENDIX B FOR CHARACTER DESCRIPTIONS ...... 259

D DENTAL MEASUREMENTS OF EARLY MIOCENE CAMELIDS FROM SUBTROPICAL AND TROPICAL ASSEMBLAGES FROM NORTH AMERICA. .. 260

E DESCRIPTION OF DENTAL CHARACTERS USED IN THE PHYLOGENETIC ANALYSIS OF EARLY MIOCENE CAMELIDAE (CHAPTER 3). ALL CHARACTERS TREATED AS UNORDERED...... 290

F CHARACTER-TAXON MATRIX USED IN THE PHYLOGENETIC ANALYSES OF EARLY MIOCENE CAMELIDAE (CHAPTER 3)...... 293

G DENTAL MEASUREMENTS OF EARLY MIOCENE TAYASSUIDS FROM PANAMA ...... 294

H DENTAL CHARACTERS USED IN THE PHYLOGENETIC ANALYSIS OF TAYASSUIDAE (CHAPTER 4) ...... 306

I CHARACTER-TAXON MATRIX USED IN THE PHYLOGENETIC ANALYSES OF EARLY MIOCENE TAYASSUIDAE (CHAPTER 4)...... 308

J EARLY MIOCENE UNGULATE OCCURRENCES FROM PANAMA ...... 309

K EARLY MIOCENE UNGULATE SPECIES FROM PANAMA ...... 325

LIST OF REFERENCES ...... 331

BIOGRAPHICAL SKETCH ...... 344

LIST OF TABLES

Table page

1-1 Mammalian content of the early Hemingfordian Centenario Fauna. Culebra and Cucaracha Formations, Panama Canal area. Modified from MacFadden et al., (2014)...... 30

1-2 Mammalian content of the late Arikareean Lirio Norte Local Fauna. Upper part of the Las Cascadas Formation, Panama Canal area. Modified from Bloch et al., (2016)...... 31

2-1 Summary table of dental measurements (in mm) of Paratoceras aff. P. tedfordi from the Las Cascadas Formation...... 74

2-2 Summary table of dental measurements (in mm) of Paratoceras orarius sp. nov from the upper Culebra Formation...... 76

2-3 Summary table of dental measurements (in mm) of P. coatesi sp. nov from the Cucaracha Formation and P. wardi from the Barstovian Trinity River L. F. .. 77

3-1 Comparative measurements (in mm) of the camelid skulls from Panama and the Central Plains discussed in this chapter...... 148

3-2 Summary table of dental measurements (in mm) of Floridatragulus sp. nov. from the late Centenario Fauna (Upper Cucaracha Formation), Panama...... 149

3-3 Summary table of dental measurements (in mm) of Floridatragulinae gen. et. sp. nov. from the upper part of the Las Cascadas Formation, Panama...... 150

4-1 Summary table of dental measurements (in mm) of to Hesperhyinae n. gen. A & sp. A from the Lirio Norte Local Fauna (Upper Las Cascadas Formation). 212

4-2 Summary of the comparative measurements (in mm) of the tayassuid dentitions and skulls discussed in this chapter...... 213

4-3 Summary table of dental measurements (in mm) of to Hesperhyinae n. gen. A & sp. B from early Centenario Fauna (upper part of the Culebra Formation)...... 215

4-4 Summary table of dental measurements (in mm) of to Hesperhyinae n. gen. B & sp. A from late Centenario Fauna (upper part of the Cucaracha Formation)...... 217

5-1 Minimum Number of individuals (MNI) calculated based on the occurrence of ungulate tooth positions in early Miocene sequences from Panama...... 239

5-2 Alpha diversity indexes calculated using PAST 3.0.1 for the early Miocene ungulates from the Panama Canal Area...... 242

A-1 Dental measurements of Paratoceras from the early Miocene of Panama...... 251

D-1 Dental measurements (upper dentition) of early Miocene camelids from Southern North America...... 260

D-2 Dental measurements (lower dentition) of early Miocene camelids from Southern North America...... 270

E-1 Lower m3 dimensions...... 285

G-1 Dental measurements of tayassuids from the early Miocene of Panama...... 294

J-1 Early Miocene Ungulate occurrences from Panama...... 309

K-1 Relative abundance of artiodactyls from Panama expressed as Minimun Number of Individuals (MNI) calculated on the occurrence of partial dentitions...... 325

LIST OF FIGURES

Figure page

1-1 Location and stratigraphic position of mammalian fossils from the Gaillard Cut, Panama Canal area...... 29

2-1 Location and biochronology of the protoceratine-bearing fossil faunas discussed in this study...... 63

2-2 Upper dentition of Paratoceras aff. P tedfordi from the late Arikareean Lirio Norte L. F...... 65

2-3 Lower dentition of Paratoceras aff. P. tedfordi from the Lirio Norte L. F...... 66

2-4 Bivariate plots of the natural logarithm of the anterior-posterior length versus maximum transverse width of the lower p4 for relevant specimens of Protoceratidae and their biostratigraphic distribution...... 67

2-5 Natural log-ratio diagram for dental measurements of Paratoceras spp. using Protoceras celer as a standard for comparison (straight line at zero)...... 68

2-6 Lower dentition of Paratoceras orarius sp. nov. from the upper Culebra Formation, UF 271625 (holotype), partial dentary with left p3-m3, left c1...... 69

2-7 Male partial skull of Paratoceras coatesi with right P4-M3 and left M1-M3, UF 223585 (holotype)...... 70

2-8 Detailed photographs of upper dentition of Paratoceras coatesi...... 71

2-9 Lower dentition of Paratoceras coatesi, UF 271182 (paratype), paired mandibles with Rp1; Rp3-m3; Lp1; Lp3-m3 and symphysis...... 72

2-10 Hypothetical relationships of the early Miocene protoceratines from Panama within protoceratinae based on a 15 character matrix with Heteromeryx dispar as the outgroup...... 73

3-1 Location and biochronology of the Oligocene-Miocene camelid-bearing fossil faunas discussed in this study...... 133

3-2 Partial rostrum of Aguascalientia panamaensis Rincón et al., 2012 from the Lirio Norte L. F. UF 281478, partial skull with partial maxillae, partial nasals, RC1-P4, LC1 (partial) and Lp2...... 134

3-3 Upper permanent and deciduous dentition of Floridatragulus sp. nov from the early Hemingfordian Centenario Fauna...... 135

3-4 Holotype of Floridatragulus sp. nov from the Centenario Fauna. UF 267194, partial left mandible with p4-m3...... 136

3-5 Holotype of Floridatragulus sp. nov from the Centenario Fauna...... 137

3-6 Detailed view of the symphysis and the rooth of p1 of Floridatragulus sp. nov...... 138

3-7 Morphological variation on lower m3s from different populations of early Miocene higher camelids from southern North America...... 139

3-8 Metatarsus of Floridatragulus sp. nov. from the Hemingfordian Centenario Fauna in Panama...... 140

3-9 Variation in tooth dimensions (in natural log scale) observed in higher fossil camelids from North America...... 141

3-10 CT scan surface model of the skull of Floridatragulinae gen. et. sp. nov. (UF 280670) from the Lirio Norte L. F. in Panama...... 142

3-11 Detailed view of the anterior part of the skull of Floridatragulinae gen. et. sp. nov. from the Lirio Norte L. F. showing the distinctive maxillary constriction posterior to the P1 present in UF 280670...... 143

3-12 Dorsal detailed view of the skull of Floridatragulinae gen. et. sp. nov. from the Lirio Norte L. F...... 144

3-13 Upper dentition of Floridatragulinae gen. et. sp. nov. from the Lirio Norte L. F...... 145

3-14 Lower dentition of Floridatragulinae gen. et. sp. nov. from the late Arikareean Lirio Norte L. F. in Panama...... 146

3-15 Hypothetical relationships of the early Miocene camelids from tropical and subtropical Central America based on a 37-character matrix with Eotylopus reedi as the outgroup...... 147

4-1 Location and biochronology of the Oligocene-Miocene tayassuid-bearing fossil faunas discussed in this study...... 203

4-2 Upper and lower dentition of Hesperhyinae n. gen. A & sp. A ...... 204

4-3 Scatter plot of the tooth dimensions (in natural log scale) measured the late Oligocene to early Miocene tayassuids from southern North America and Panama discussed in this chapter...... 205

4-4 Partial skull (holotype) of Hesperhyinae n. gen. A & sp. B from the early Centenario Fauna...... 206

4-5 Detail of the upper dentition of UF 224400, partial skull of to Hesperhyinae n. gen. A & sp. B from the early Centenario Fauna ...... 207

4-6 Lower dentition of Hesperhyinae n. gen. A & sp. B from the early Centenario Fauna, Upper Culebra Formation, Panama Canal area ...... 208

4-7 Partial upper molars of aff. Floridachoerus sp. from the early Centenario Fauna (upper Culebra Formation), Panama Canal area...... 209

4-8 Lower dentition of Hesperhyinae n. gen. B & sp. A from the late Centenario Fauna, PAC-4 area, Panama Canal...... 210

4-9 Hypothetical relationships of the early Miocene bunodont tayassuids from North America based on a 24-character matrix with Perchoerus probus as the outgroup...... 211

5-1 Rarefaction Curves calculated for individual localities (YPAs) along the Panama Canal area...... 237

5-2 Rarefaction Curves calculated after integrating ungulate fossils from the late Arikareean Lirio Norte L. F. and the early Hemingfordian Centenario Fauna. .. 238

Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulillment of the Requirements for the Degree of Doctor of Philosophy

SYSTEMATICS, BIOSTRATIGRAPHY, AND PALEOBIOGEOGRAPHY OF EARLY MIOCENE ARTIODACTYLS FROM THE PANAMA CANAL, PANAMA, CENTRAL AMERICA By

Aldo Fernando Rincón

December 2016

Chair: Jonathan I. Bloch Major: Geology

The diversity of extant and fossil ungulates provides multiple examples to adaptation to different kinds of herbivory. Artiodactyls today are a diverse and important component of many terrestrial ecosystems, including those at low latitudes, yet their evolutionary history in the New World Tropics is largely unknown. Here I describe, for the first time, fourteen artiodactyl taxa recovered from two temporally distinct faunas from the early Miocene (19-21 Ma) of Panama. I provide a hypothetical framework for the relationships of these taxa to those found at higher latitudes that are discussed in the context of the broader fossil record of North American artiodactyls. Results suggest tropical speciation and endemism, with limited dispersals to higher latitudes for some groups characterized by relatively bunodont dentitions likely indicative of more generalized herbivorous diets. In Panama, the late Arikareean (~21 Ma) is characterized by a relative abundance of endemic North American ungulates with both tropical

(floridatraguline camels, protoceratids) and temperate (equids, peccaries, blastomericines, and entelodonts) affinities. In contrast, the early Hemingfordian (~19

Ma) is dominated by artiodactyl taxa with exclusive tropical affinities while ungulates with temperate affinities are relatively less abundant. Differences in faunal composition

the early Miocene assemblages might be due to orographic and phytogeographic processes and only ruminants (blastomerycines) persisted with no change in relative abundance. Physical and environmental change (from highly perturbed volcanic terrains to a wetter tropical forest) was essential in triggering evolutionary change on tropical endemic ungulate groups that are closely related to early representatives of modern groups that diversified in more temperate latitudes during the middle Miocene.

CHAPTER 1 INTRODUCTION

A better understanding the Neogene biogeographic history of early Miocene vertebrate communities from Panama represents an unexcelled opportunity to investigate the origin of modern tropical biodiversity in context of dynamic landscape evolution in a tropical volcanic terrain. The stratigraphic interval preserved in the

Panama Canal basin (Figure 1-1) is one of the most complete and best-exposed

Oligocene and Miocene volcanic sequences of the Central American arc. While

Paleogene fossil evidence of terrestrial mammalian communities in southern North

America includes scattered fossil assemblages from Mexico (Webb et al., 2003;

Ferrusquía-Villafranca, 1984; Jiménez-Hidalgo et al., 2015; Ferrusquía-Villafranca,

2006; Prothero et al., 2013), evidence of terrestrial communities in marginal tropical areas of southern North America (Panama Canal basin, Lat. ~9 N) is restricted to the earliest Miocene (Rincón et al., 2012; Bloch et al., 2016). In addition to their tropical location, early Miocene terrestrial fossils from Panama provide evidence for how these ancient terrestrial ecosystems developed in a unique tectonic province: the transition zone between the Chorotega (western Panama and Costa Rica) and Chocó (eastern

Panama and Western Colombia) tectonic blocks (Case, 1974; Dengo, 1985; Duque-

Caro, 1990). These tectonic blocks, corresponding to the early Miocene southern

Central American peninsula, underwent progressive uplift from approximately 12 to 4.8

Ma leading to the disruption of pelagic marine depositional environments about 8 to 9

Ma (Coates et al., 2004). This interval roughly corresponds to northward mammalian overwater dispersal between South and southern North America as denoted by the

earlier occurrence of sloths in North America prior to the onset of the GABI in the

Pleistocene (Woodburne, 2004; Woodburne et al., 2010).

Despite its proximity to South America (Montes et al., 2012), all early Miocene ungulates from Panama have Holarctic affinities (Whitmore and Stewart, 1965;

MacFadden et al., 2006). Furthermore, results presented in this dissertation suggest a direct relationship between the earlier occurrences of certain taxa (e.g. Paratoceras and

Aguascalientia) in Panama (21-19 Ma) to ungulates found in younger (late Miocene) and more temperate fossils assemblages from the Gulf Coast. This pattern is consistent with the presence of a distinctive biogeographic province that would have connected areas of the Gulf Coast with the Panama Canal basin from the early Miocene

Hemingfordian NALMA (MacFadden et al., 2010; MacFadden et al., 2014; Rincón et al.,

2012; Rincón et al., 2013; Rincón et al., 2015) through at least the late Miocene

(MacFadden et al., 2015). In this context, the floral (pollen record) composition of the forest in the southernmost part of this tectonic province is of particular note, with the early Miocene (~19 Ma) Panamanian tropical rain forest dominated by angiosperms with

South American (Gondwanan) affinities (Jaramillo et al., 2014), while forests further north were more Laurasian in their affinities (Bloch et al., 2016). As such, the mammals present in this nearly continuous biogeographic province seem to occupy a variety of very distinct biomes, from tropical South American-derived rainforest in Panama to the more temperate Laurasian-derived forest of Florida. While the taxonomic affinities for many of the terrestrial mammals from the underlying Lirio Norte L. F. (~21 Ma) are similar in having distinctly North American relationships, recent discoveries indicate a more complicated paleobiogeographic scenario for others. Recovered mammalian

fossils not only include isolated teeth of a platyrrhine monkey (Bloch et al., 2016) with clear South American affinities, the fossil assemblage also includes the earliest occurrence (~2 Ma older) in Panama of Euro-asiatic immigrant taxa such as procyonids and the sciurid Petauristodon (Bloch et al., 2016; Rincón et al., 2014). This pattern suggests that mammalian commiunities (including ungulates) appearing in the Gulf

Coast during the Hemingfordian NALMA might have had an earlier yet undefined biological history in tropical areas of southern North America. As such, immigrants that colonized tropical areas of southern North America ~21 Ma ago did so without representation in the known fossil record of the Great Plains and the Gulf Coast until the earliest Hemingfordian NALMA (~19 Ma).

Independent lines of evidence suggest that the earliest Miocene was a relatively cold period preceding warmer conditions during the Middle Miocene with distinctive increasing pCO2 levels, and intense volcanic activity along the western margin of North

America (Graham, 1999; Kürschner et al., 2008) and even high latitude areas in the

Eurasia (Kürschner and Kvacek, 2009). The conjunction of these abiotic factors may have led to drastic biotic perturbations representing a challenge for North American mammalian communities, ultimately leading to diversification and colonization of marginal tropical terrains of Panama ca. 21 Ma. Whether the dispersal of terrestrial vertebrates was controlled by a continuos land connection between Panama and the

Gulf Coast or even South America, it seems reasonable to hypothesize that the biogeographic history of these mammalian faunas, although complex, was actively affected by biotic (floral composition) and abiotic (volcanism) factors that controlled the distribution of suitable habitats and, ultimately, led to vicarience among mammals

inhabiting distinctive ecological niches (or adjacent faunal provinces). These newly emerged early Miocene tropical biomes offered an open landscape ready for colonization, providing a novelty of food resources not present in more temperate areas of southern North America.

Terrestrial earliest Miocene (Arikareean North American Land Mammal Age-

NALMA) fossil mammals are uncommon in Central America and their fragmentary record is mostly restricted to the Central Great Plains (Nebraska), the Texas Gulf

Coastal Plain, and a few isolated local faunas in Florida, Mexico and California (Tedford et al., 2004). Within the Arikareean NALMA (see Tedford et al., 2004; Albright et al.,

2008), ungulate mammals from the latest Arikareean (Ar4, 23 - 18.5 Ma) are known from temperate (>30 N Lat) fossil assemblages from Oregon (Albright et al., 2008), and

Nebraska (Tedford et al., 2004) and subtropical areas from Mexico and the Gulf Coast

(Webb et al., 2003; Tedford et al., 2004; Patton, 1969; Patton, 1978).

In a more regional context, pronounced changes in vegetation documented during the Oligocene–Miocene transition in the Central Great Plains (Stromberg, 2006;

Kürschner, 2008) suggest that floral and climatic turnover is likely linked to morphological adaptations and changes in selection pressure in a large number of terrestrial mammalian herbivores (Janis, 2002; Stromberg, 2002; Stromberg, 2006).

Furthermore, these changes in the composition in the ungulate populations of North

America are coeval with changes in composite stable isotope records from the

Northeastern Pacific. In the marine record, changes in the concentration of stable isotopes and trace metals identified in marine populations started during the early

Oligocene and continued into the earliest Miocene (Oi-1 and Mi-1 respectively) (Lear et

al., 2004). Furthermore, these isotope events have been linked to increased continental ice volume, changes in the pCO2 and, surprisingly, increased deep-sea temperature

(Lear et al., 2004) suggesting that these climatic and floral changes could be synchronous worldwide. Consequently, these climatic perturbations might have been responsible for the remarkable morphological disparity (turnover) observed in different early Miocene fossil assemblages in North America.

Biostratigraphic correlations with other assemblages from North America suggested that the Panamanian fossiliferous sequences include the oldest occurrence of taxa previously known only from younger sediments from Florida, Texas and Mexico

(Slaughter, 1981; MacFadden, 2006; Kirby et al, 2008; MacFadden et al, 2010; Rincón et al., 2012; MacFadden et al., 2014). However, the association of small-sized parahippine equids and floridatraguline camels in the Lirio Norte L. F. contrasts with the rhinoceroses, protoceratids, equids, and peccaries recovered from the younger

Centenario Fauna (MacFadden, 2006; 2009; MacFadden et al., 2010; 2014) suggesting that abiotic (e.g. volcanism) and/or biotic (e.g. habitat structure) factors might be responsible for these differences in the faunal composition. Preliminary comparisons of these late Arikareean ungulates to more temperate early Miocene faunas from the southern U.S. and Mexico defined a biogeographic province connecting southern

Central America with Holarctic terrains (MacFadden, 2006). Recent palynological studies focused on early Miocene terrestrial and shallow marine sequences from tropical sequences from Panama showed that the composition of the forest was unusual. While the majority of the fossil mammals from Panama have Holartic affinities, the taxonomic affinities of the early Miocene (~19 Ma) forest suggest that an

interchange between floras of North and South America was already happening during the early Miocene (Jaramillo et al., 2014).

Herein I discuss the biostratigraphic and paleobiogeographic implications of recently recovered early Miocene mammalian fossils from Panama by comparing different artiodactyl groups from Panama with those from Mexico, the Gulf Coast, and the Great Plains. Additionally, I discuss the phylogenetic relationships between these new fossils and earlier representatives of modern groups in a recently updated paleobiogeographic context. Furthermore, I discuss the relationship between paleogeography and diversification of artiodactyls to test if the earlier occurrence of representatives of modern artiodactyl groups appearing during the early Hemingfordian is the result of intense diversification processes associated with major changes in the landscape in the tropical volcanic areas of southwestern North America, the Central

American Volcanic Arc (Mann et al., 2007). Alternatively, the appearance of modern ungulate clades in higher latitudes during the late early Miocene (late Hemingfordian and early Barstovian NALMAs) might have been the result of a late Hemingfordian diversification phase associated with increasingly drier conditions that were not necessarly linked to the volcanic and tectonic activity of the Central American Volcanic

Arc. As consequence, these biotic and abiotic changes, that likely started during the

Arikareean, where responsible for the gradual extinction of the tropical and subtropical endemic clades inhabiting southern North America during the early Neogene. Although this research focuses mainly on the systematics, biostratigraphy, and paleobiogeography of fossil artiodactyls, the inferred paleobiogeographic patterns are

further discussed to identify a different line of evidence to explain the biostratigraphic anomalies observed in the early Miocene fossil record of southern North America.

Conventions

Biochronology follows the Late Oligocene-Early Miocene biozonations developed in the Great Plains (Tedford et al., 1987, 1996, 2004) and the consequent recalibration proposed by Albright et al., (2008) for the Arikareean North America Land Mammal Age

(NALMA) in Oregon.

For selenodont artiodactyls (protoceratids and camelids), dental terminology follows the nomenclature proposed by Gazin (1955) which includes the use of

“metaconule” for the posterior lingual cusp for camelidae given the fact that in ancestral artiodactyls (e.g., oreodonts) the position of the hypocone is occupied by the enlargement of the metaconule (Miller and Wood, 1963; Gazin, 1955; Patton, 1967). For deciduous dentitions, cusp terminology follows Loring and Wood (1969), and it fundamentally differs from that of permanent dentition in the retention of a homologous cusp equivalent to the hypoconule in the upper deciduous premolars (Rincón et al.,

2012). Given the general dental similarities of selenodont taxa and ruminants, cusp terminology follows the nomenclature proposed by Bärmann and Rössnerb (2011) for the description of the intercolumnar pillars (herein referred as ectostylids for upper molars and entostylids for lowers). For bunodont artiodactyls (tayassuids), dental terminology follows the nomenclature proposed by Woodburne (1969) and later modified by Prothero (2015) in which the posterolingual cusp on tayassuid upper molars is described as a hypocone. I use these terms for convenience in description, not to imply serial homology with molar cusps.

Dental dimensions. Measurements were taken at the base of the crown to minimize the variation in tooth dimensions due to wear. Crown dimensions are reported as the maximum anterioposterior length (APL in mm) and the maximum transverse width (MTW in mm) measured just above the dentin-enamel junction and along the midline of the tooth. Anteroposterior length (APL) was measured at the dentine enamel junction for all teeth except for those from the Texas Memorial Museum (TMM), which were measured at the widest portion of the tooth. For m3s, additional TWL values were measured at the basal part of the hypoconulids. PAST 3.07 was used for statistical analyses (Hammer et al., 2001).

Three-dimensional data acquisition. The following artiodactyl specimens, UF

267048, a partial skull of a new genus and species of flordiatraguline camelid from the

Lirio Norte L. F., UF 257204, left complete metatarsal of Floridatragulus sp. from the late Centenario Fauna, and UF 234400, a partial skull of new genus and species of hesperhyene tayassuid were scanned at the Duke University Shared Materials

Instrumentation Facility in Durham, North Carolina, using a Nikon XTH 225 ST MicroCT scanner. The three-dimensional microCT data presented here, including shape files and the original tiff stacks, will be made publicly available on Morphosource (Boyer et al.,

2014; www.morphosource.org) upon publication of the study.

Institutional Abbreviations

 AMNH. American Museum of Natural History, New York, U.S.A;

 ANSP. Academy of Natural Sciences, Philadelphia, Pennsylvania, U.S.A;

 CM/CMNH. Carnegie Museum, Pittsburgh, Pennsylvania;

 F:AM. Frick: American Mammals collection at the AMNH;

 LACM (CIT). California Institute of Technology Collection, Los Angeles County Museum; Los Angeles, California, U.S.A;

 LSUMG-V, Louisiana State University Museum of Geoscience; Baton Rouge, Louisiana, U.S.A;

 MZC. Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, U.S.A;

 SDSM. South Dakota School of Mines, Rapid City, South Dakota, U.S.A;

 SMU. Southern Methodist University, Dallas, Texas, U.S.A;

 TMM. Texas Memorial Museum, Austin, Texas, U.S.A;

 UCMP. University of California Museum of Paleontology, Berkeley, U.S.A;

 UF. Vertebrate Paleontology Collection, Florida Museum of Natural History, University of Florida, Gainesville, Florida, U.S.A;

 UF/MC. Mammalogy Collection, Florida Museum of Natural History, University of Florida, Gainesville, Florida, U.S.A;

 UNSM. University of Nebraska State Museum, Lincoln, U.S.A;

 USNM. United States National Museum, Smithsonian Institution, Washington, D.C., U.S.A.

Geological Setting

During the Oligocene an important change in the tectonic configuration of Central

America occurred at 25-23 Ma. The Farallon plate broke apart forming two distinct, smaller tectonic plates, the Cocos and Nazca plates (Mann and Kolarsky, 1995; Coates et al., 2004; Farris et al., 2011; Barat et al., 2014). A resulting temporary interruption of magmatic activity, which started in the Paleocene-Eocene (58-39 Ma), is inferred between 38 and 27 Ma before initiation of a new magmatic phase 25-15 Ma. Since the start of the late Miocene collision between the Choco block and South America, eastern

Panama (east from El Valle Volcano) has remained a non-volcanogenic area (Mann and Kolarsky, 1995; Barat et al., 2014). The Chorotega and Choco blocks are mainly

composed of plateau and arc rocks intruded by Campanian to Eocene intermediate plutonic rocks latter segmented during late Eocene-early Oligocene (38 to 28 Ma). This segmentation was almost completed by late Oligocene times (25 Ma) and subsequent deformation (rotation) with opposite directions is responsible of the curvature of the

Panama Isthmus (the Chorotega block rotated counter clockwise whereas the Choco block rotated clockwise). After retro-deforming these blocks, the space for the Central

American seaway narrowed at 25 Ma (Montes et al., 2012), likely disappearing by about

15 Ma (Montes et al., 2015).

The early Miocene panamanian fossil record. Since the original description of the early Miocene Panamanian fossils by Whitmore and Stewart (1965), the mammalian fauna now includes five terrestrial orders. Seventeen mammalian genera representing

14 families are known from the Centenario Fauna while 18 genera representing 13 families are known from the late Arikareean Lirio Norte Local Fauna (L. F.) (MacFadden et al., 2014; Bloch et al., 2016). In a lithostratigraphic context, the late Arikareean (~21

Ma) Lirio Norte (L. F.) represents terrestrial mammalian communities from the uppermost part of the Las Cascadas Formation (Figure 1-1). This interval includes discrete fossiliferous sequences of subaerial volcanic products deposited (Rincón et al.,

2012a, 2012b, 2013, Bloch et al., 2016) in sporadic fluvial settings. In contrast, the early

Hemingfordian (~19 Ma) Centenario Fauna (MacFadden et al., 2010; MacFadden et al.,

2014) encompasses mammals recovered from volcaniclastic sequences from the upper part of the Culebra and Cucaracha Formations (Figure 1-1). These taxa inhabited a variety of sedimentary environments ranging from deltaic sequences of the upper part of the Culebra Formation to transitional and paralic sequences from the upper part of the

Cucaracha Formation (Kirby and MacFadden, 2005; MacFadden et al., 2014; Rincón et al., 2015a). The unfossiliferous volcanic and volcaniclastic Pedro Miguel Formation was deposited after the accumulation of the continental paleosols of the upper part of the

Cucaracha Formation, and represents the youngest lithostratigraphic unit in the Gaillard

Cut area (Montes et al., 2012; Kirby et al., 2008; MacFadden et al., 2014; Rincón et al.,

2015a).

The lower part of the Las Cascadas Formation encompassed massive accumulation of volcanic rocks (mainly agglomerated breccias) while the upper part

(Figure 1-1) includes volcanic and volcanoclastic rocks ranging from welded tuffaceus agglomerates to pyroclastic fall deposits, with discrete intervals of fluvial sediments

(Woodring, 1982; Kirby et al., 2008, Montes et al., 2012; Bloch et al., 2016). The age of the lower boundary of the Las Cascadas Formation is constrained by andesitic water- saturated arc lavas of the underlying Bas Obispo Formation dated using Ar40/Ar39 at

25.37 ± 0.13 Ma (Rooney et al., 2010). Vertebrate fossils in the las Cascadas Formation are associated with andesitic flows and agglomeratic tuffs with cobbles of andesite and basalt embedded in a fine-grained tuffaceous matrix (Figure 1-1) that recently produced

U/Pb ages on magmatic zircons of 20.93 ± 0.17 (Bloch et al., 2016). Therefore, the duration of the Las Cascadas Formation likely spans the late Oligocene to early

Miocene (~25 Ma to ~21 Ma), representing the middle-to-late Arikareean NALMA sensu

MacFadden and Hunt (1998) and Albright et al. (2008). The Las Cascadas Formation is overlain by the Culebra Formation and separated from it by a slightly angular unconformity (Montes et al., 2012). The overlaying volcaniclastic sequence includes a marine transgressive system of the Culebra Formation and the prograding sequence of

the Cucaracha Formation (Kirby et al., 2008). The Centenario Fauna of MacFadden et al. (2010) is derived from volcaniclastic (deltaic and paralic) sequences from the upper

Culebra Formation and fine-grained (flood plain to paralic environments) sequences of the upper Cucaracha Formation (MacFadden et al., 2010; MacFadden et al., 2014;

Rincón et al., 2015a). In contrast to other fossil vertebrate faunas of long duration, e.g., the Clarendon Fauna from Texas (Tedford et al., 2004), there is no overlap at the species level between fossils recovered from the upper part of the Culebra Formation and the Cucaracha Formation. The Culebra Formation is characterized by fossil taxa inhabiting more transitional environments (prodelta) and are herein referred to as the early Centenario Fauna, while the Cucaracha Formation is characterized by fossils

(herein referred to as the late Centenario Fauna) found in flood plain environments with no influence of marine influx (Montes et al., 2012; Rincón et al., 2015). It should be noted, however, that fossil vertebrate taxa formally described from the upper part of the

Culebra Formation only include two artiodactyl species, the tayassuid “Cynorca” occidentale and the protoceratine Paratoceras orarius (MacFadden et al., 2010; Rincón et al., 2015); therefore, some overlap at the species level between the two formations can be expected as collecting activities increase in the Lirio Area.

Presence of early Miocene shallow marine sequences intercalated with terrestrial

(fossiliferous) sequences in the Las Cascadas and Cucaracha formations suggest that although the colonization by plants and animals of the aerially exposed rocks of

Chorotega block started as early as the earliest Miocene, a land connection with more temperate terrains in North America might not have been continuous through the early

Miocene. However, a remarkable phytogeographic process had already started in

tropical areas of southern North America by the early Miocene (~19 Ma). Floral elements with Gondwanan (South American) affinities dominated the Panamanian forest (Jaramillo et al., 2014), while the majority of terrestrial mammalian groups exhibit unambiguous Holarctic affinities (MacFadden 2006; Rincón et al., 2015). The only exception to this pattern is represented by a South American monkey recently described from the Lirio Norte L. F. (Bloch et al., 2016) and also the occurerence of nonmammalian vertebrates with inferred South American affinities (Hastings et al.,

2013; Head et al., 2012).

This distinctive phytogeographic scenario may have been an important factor for any vertebrate species attempting to colonize these forested tropical areas.

Furthermore, the distinctiveness of the early Miocene Panamanian forest played a main role in the subsequent diversification of tropical endemic browsers (e.g. protoceratine protoceratids, floridatragulines), and likely controlled the dispersion to higher latitudes by highly specialized herbivores (Bloch et al., 2016). Consequently, the diversification of ungulates may have been enhanced by the interaction of these communities with the habitat rather than by the presence/absence of continuous land connection between volcanic terrains of southern North America and other sequences from the Gulf Coast.

Biostratigraphy of Early Miocene Terrestrial Mammals from Panama

The Lirio Norte L. F. includes the occurence of terrestrial vertebrates associated with volcanic products that have been recently dated as deposited 20.93 ± 0.17 Ma

(Table 1-1; Bloch et al., 2016). This radiometric date is consistent with the occurrence of the late Arikareean diagnostic taxa like the amphicyonid Cynelos sp. (Rincón et al.,

2015). In contrast, fossil mammals from the Centenario Fauna (Table 1-2) include fossil specimens collected from a larger stratigraphic interval (~115 meters) that

encompasses the the Culebra and Cucaracha Formations (MacFadden et al., 2010).

Ar/Ar ages calculated on biotite associated to the Cucaracha Tuff placed the Centenario

Fauna near ~19 Ma and more specifically, in the C5rn paleomagnetic zone (MacFadden et al., 2014). The occurrence of the three-toed horse Anchitherium clarencei, the procyonid Bassaracyoniodes sp., the sciurid Petauristodon sp., and the rhinoceros

Floridaceras whitei are consistent with an early Hemingfordian age based on comparisons to faunas from higher latitudes of North America (MacFadden et al., 2014).

However, I note that there are older ocurrences of some of these taxa in Panama than what is found at higher latitudes. Specifically, the late Arikareean Lirio Norte L. F. includes the oldest ocurrence of procyonids and the sciurid Petauristodon in North

America (Bloch et al., 2016).

Figure 1-1. Location and stratigraphic position of mammalian fossils from the Gaillard Cut, Panama Canal area. A) Map of Central America showing the location of the Panama Canal area (Gaillard Cut). B) Stratigraphic section of the Gaillard Cut area showing the stratigraphic position of the Lirio Norte Local Fauna (L. F.) and the Centenario Fauna. Modified from Rincón et al. (2015) and Bloch et al., (2016). Abbreviations: Ar, Arikareean North American Land Mammal Age (NALMA); Ba, Barstovian NALMA; Cl, Clarendonian NALMA; He, Hemingfordian NALMA.

Table 1-1. Mammalian content of the early Hemingfordian Centenario Fauna. Culebra and Cucaracha Formations, Panama Canal area. Modified from MacFadden et al., (2014). ORDER FAMILY GENUS Chiroptera Phyllostomidae Undescribed Rodentia Family Jimomyidae Undescribed Family Sciuridae Undescribed Family Heteromyidae Undescribed Carnivora Family Canidae Undescribed Family †Amphicyonidae Undescribed Family Procyonidae Bassaricyonoides Order Artiodactyla Family Tayassuidae Hesperhyinae n. gen. A & sp. B Hesperhyinae n. gen. B & sp. A Family †Oreodontidae Merycochoerus matthewi Family †Protoceratidae Paratoceras coatesi sp. nov. Paratoceras orarius sp. nov. Family Camelidae Floridatragulus sp. nov Family Moschidae Parablastomeryx Order Perissodactyla Family Equidae Anchitherium clarenci Archaeohipus sp. Family Rhinocerotidae Floridaceras whitei

Table 1-2. Mammalian content of the late Arikareean Lirio Norte Local Fauna. Upper part of the Las Cascadas Formation, Panama Canal area. Modified from Bloch et al., (2016). ORDER FAMILY GENUS Chiroptera Phyllostomidae Undescribed Rodentia Family Jimomyidae Undescribed Family Sciuridae Undescribed Family Heteromyidae Undescribed Carnivora Family †Amphicyonidae Undescribed Family Procyonidae Undescribed Order Artiodactyla Family Tayassuidae Hesperhyinae n. gen. A & sp. A Family †Protoceratidae Paratoceras aff. P. tedfordi Protoceras aff. P. neatodelpha Family Camelidae Aguascalientia panamaensis A. minuta Floridatragulinae gen. et. sp. nov. Family Moschidae Blastomerycinae inc. sed. Order Perissodactyla Family Equidae cf “Parahippus” sp.

Family Rhinocerotidae Inc. sed. Family Calichotheriidae Inc. sed Order Primates Family Cebidae Panamacebus

CHAPTER 2 EARLY MIOCENE FOSSIL PROTOCERATIDS (PROTOCERATINAE) FROM PANAMA

The Protoceratidae are characterized by an unusual cranial morphology among artiodactyls that includes the evolution of rostral cranial appendages (ossicones). The origin and evolution of the group has been the subject of debate since the establishment of the family by O. C. Marsh in 1891 when he described Protoceras celer Marsh, 1891 from the late Oligocene of North America. Protoceratids first appear in the North

American fossil record during the late Eocene and persisted in subtropical areas until the late Miocene (Prothero, 1998). Although hypertragulid and pecoran affinities (e. g.

Matthew, 1905; Frick, 1937; Scott, 1940; Stirton, 1944; Simpson, 1945; Gazin, 1955) were initially proposed, hypothetical tylopod affinities were subsequently suggested based on similarities in the structure of the pes in the late Eocene hornless protoceratids and other more derived forms (Gazin, 1955; Stirton, 1967; Patton and

Taylor, 1973; Webb and Taylor, 1980; Wilson, 1974). These shared morphological similarities provided evidence for the idea that Camelidae was the sister group to

Protoceratidae (including the primitive leptotragulines) with both groups the products of a late Eocene North American radiation of selenodont artiodactyls (Black, 1978; Webb and Taylor, 1980). However, later comparative work focused on basicranial morphology argued that protoceratids lacked obvious synapomorphies shared with Camelidae and highlighted the need for a systematic revision of North American Neogene fossil artiodactyls with cranial appendages (Joeckel and Stavas, 1996).

By the late Oligocene, male protoceratids exhibit a variety of cranial appendages that are unique among North American artiodactyls (Marsh, 1897; Prothero, 1998).

Based on the morphology of these appendages and their associated dentitions, Frick

(1937) initially proposed three Neogene subfamilies within his hypertragulid family

Protoceratidae: 1) Synthetoceratinae including the more hypsodont forms; 2) a monospecific Syndyoceratinae; and 3) Protoceratinae, including species referred to

Paratoceras Frick, 1937 and Protoceras Marsh, 1891 (including the female skull of

Calops Marsh, 1894). In a comprehensive taxonomic revision of the group, Patton and

Taylor (1973) classified the non-synthetoceratine protoceratids within Protoceratinae based on fossils from the Great Plains and Gulf Coast, but excluded those primitive forms previously linked to Hypertragulidae and Camelidae. A subsequent revision of the

Protoceratidae (Prothero, 1998) incorporated the tylopod relationships proposed by

Black (1978) and Webb and Taylor (1980) and included the late Eocene-early

Oligocene basal members proposed by Wilson (1974), Gazin (1955) and Emry and

Storer (1981). Consequently, three ranks within Protoceratidae were proposed: (1) the hornless or basal protoceratids; (2) the monophyletic Synthetoceratinae of Webb, 1981; and (3) the informal “Protoceratinae” sensu Prothero (1998).

The primitive Eocene-Oligocene hornless protoceratids inhabited a wide geographic range throughout North America, including the Great Plains and the Gulf

Coast (Gazin, 1955; Wilson, 1974). They include Leptotragulus Scott and Osborn, 1887 from the Uintan through the Chadronian North American Land Mammal Ages (NALMAs) in Wyoming, Montana, South Dakota, Nebraska, and Utah; Leptoreodon Wortman,

1898 from the Duchesnean NALMA of Saskatchewan and the Uintan of California,

Texas, and Utah; Poabromylus Peterson, 1931 from the Duchesnean of Utah,

California, Texas and the Chadronian NALMA of Wyoming and South Dakota;

Toromeryx Wilson, 1974 from the Uintan of Texas; and Heteromeryx Matthew, 1905

from the Uintan of Texas and the Chadronian of South Dakota and Nebraska (Prothero,

1998). The monophyletic Synthetoceratinae is known from early to late Miocene

(Arikareean to Clarendonian NALMAs) deposits of Wyoming, Nebraska, and the Gulf

Coast (Maglio, 1966; Stirton, 1967; Patton, 1969; Patton and Taylor, 1971; Albright,

1998; 1999) and from subtropical late Miocene (Hemphillian NALMA) deposits in the

Texas Gulf Coast (Patton, 1969; Webb, 1981). Synthetoceratines are characterized by their subhypsodont dentitions, relatively reduced premolars, elongate muzzles with a distinctively enlarged rostral ossicone formed by a fusion of the maxillary ossicones, and elevated postorbital ossicones in males (Patton and Taylor, 1971; Webb, 1981).

The late Arikareean Syndyoceras Barbour, 1905 (Tribe Kyptoceratini) from Nebraska has brachydont dentitions and is the oldest member of the subfamily. On the other hand, Prosynthetoceras Frick, 1937 was the first synthetoceratine (Tribe

Synthetoceratini) reported outside of the Great Plains reaching areas of the Gulf Coast and New Jersey during the Arikareean, Hemingfordian, Barstovian and Clarendonian

NALMAs (Patton and Taylor, 1971; Albright, 1999).

The informal subfamily “Protoceratinae” of Prothero (1998) (Figure 2-1) includes the hornless Pseudoprotoceras Cook, 1934 from the Chadronian and Orellan NALMAs of Wyoming, Nebraska, and Saskatchewan (Emry and Storer, 1981); Protoceras from the Whitneyan and Arikareean of South Dakota, Nebraska, Wyoming and Texas (Patton and Taylor, 1973; Albright, 1999) and the more tropical Paratoceras Frick, 1937 from the Arikareean, Barstovian, and Clarendonian deposits of Mexico, Texas, and the

Hemingfordian of Panama (Whitmore and Stewart, 1965; Patton, 1969; Patton and

Taylor, 1973; Webb et al., 2003; Kirby and MacFadden, 2005; MacFadden, 2006).

Early Miocene protoceratids are rare in the relatively well-sampled fossiliferous sequences of the Great Plains and are represented only by the late Arikareean protoceratine Protoceras neatodelpha Patton and Taylor, 1973 and the Hemingfordian synthetoceratine Lambdoceras Stirton, 1967. During the Neogene, synthetoceratines were not only the dominant protoceratids in subtropical fossil assemblages of the Gulf

Coast (Patton, 1969; Patton and Taylor, 1973, Albright, 1999), but also reached temperate areas of the Atlantic Coastal Plain (Tedford and Hunter, 1984). On the other hand, the more tropical protoceratines inhabited Panama (Whitmore and Stewart, 1965;

MacFadden, 2006), Mexico (Webb et al., 2003), and are documented from at least one occurrence of Paratoceras wardi in Barstovian deposits of Texas. Surprisingly,

Paratoceras is not reported from any of the other well-sampled units that comprise the

Coastal Plain yet it is reported from Miocene fossil assemblages in Mexico and Panama

(Patton and Taylor, 1973; MacFadden, 2006). By the middle to late Miocene protoceratids became increasingly rare in the Great Plains. The protoceratine

Paratoceras persisted in the Gulf Coast (Texas), while the synthetoceratine Kyptoceras persisted in Mexico and the Atlantic Coastal Plain until the early Pliocene (Hemphillian

NALMA) (Patton and Taylor, 1973; Webb et al., 2003). This, along with the more common occurrence of protoceratines in the Miocene fossil record of Texas and Central

America suggest that protoceratines could have diversified in the poorly sampled tropical areas of Central America during the Miocene prior to their last occurrence in late

Miocene deposits from Texas (Patton and Taylor, 1973; Webb, 1981). While synthetoceratines probably persisted as tropical browsers in the Gulf Coast and the

Atlantic Coastal Plain, the observed increase in crown height in Synthetoceratini and

Kyptoceratini has been interpreted to be associated with a gradual shift towards a coarser feeding capacity during increasing dry seasons throughout the Neogene (Webb et al., 2003).

An early Miocene diversification of protoceratines would have been contemporaneous with floristic changes documented in the fossil record of the Great

Plains, where a gradual replacement of woodland savannas by grass-dominated habitats has been recognized on the basis of the relative abundance of palynomorphs

(Strömberg, 2002; 2006). It has been suggested that these changes in paleoecology are associated with changes in species richness and generic diversity of ungulate browser communities during the early-middle Miocene in the Great Plains (Janis et al., 2000;

Woodburne, 2004).

The purpose of this chapter is to describe new early Miocene protoceratid fossils recently collected from three different lithostratigraphic units (Las Cascadas, Culebra and Cucaracha formations) cropping out along the Gaillard Cut in the Panama Canal area (Fig 1-1) and re-evaluate specimens (casts) originally reported by Whitmore and

Stewart (1965) and further investigated by MacFadden (2006). In order to clarify the systematic taxonomy and improve the poorly known paleobiogeography of these

Central America protoceratines, I compare the new Panamanian fossils with Neogene protoceratines from more temperate sequences of the Great Plains, the Texas Gulf coast (Patton and Taylor, 1973), and Mexico (Webb et al., 2003) in a phylogenetic context. The resulting systematic, paleogeographic, and biostratigraphic implications are discussed while also incorporating paleobotanical evidence regarding the early

Miocene tropical forest of Panama and southern Mexico.

Systematic Paleontology

Class MAMMALIA Linnaeus, 1758

Order ARTIODACTYLA Owen, 1848

Suborder TYLOPODA Illiger, 1811

Family PROTOCERATIDAE Marsh, 1891

Subfamily PROTOCERATINAE Marsh, 1891

Genus PARATOCERAS Frick, 1937

Type species. Paratoceras macadamsi Frick, 1937 from the Clarendonian

Clarendon Fauna, Texas.

Type specimen. AMNH F:AM 32457, right partial mandible with p2-m3 (broken).

Included species. Paratoceras tedfordi Webb et al., 2003 from the early Miocene

Balumtum Sandstone from the Simojovel area in the state of Chiapas, Mexico; P. wardi

Patton and Taylor, 1973 from the Barstovian Trinity River Local Fauna (L. F.) in San

Jacinto and Walker Counties, Texas; P. aff. tedfordi from the late Arikareean Lirio Norte

L. F. in Panama; P. orarius sp. nov. from the early Centenario Fauna (Upper Culebra

Formation) in Panama; and P. coatesi sp. nov. from the late Centenario Fauna (Upper

Cucaracha Formation) in Panama (Figs. 1-1, 2-1).

Comments. Frick (1937) provided the original generic description based on a partial lower dentition with Rp2-m3 (AMNH F:AM 32457) of the Clarendonian P. macadamsi Frick, 1937 from the MacAdams Ranch Quarry, Donley County, Texas

(Frick, 1937:608). Based on an exceptionally well-preserved male skull and several partial dentitions, Patton and Taylor (1973) presented a revised diagnosis for the genus and discussed its relationships with other protoceratines after describing a new species

(P. wardi Patton and Taylor, 1973) from the early Barstovian Fleming Formation, San

Jacinto County, Texas (Tedford et al., 2004). Because even partial skulls of Paratoceras are relatively rare in the fossil record, I compile the cranial and dental morphologies described by Patton and Taylor (1973) and later summarized by Prothero (1998).

The male skull of Paratoceras is characterized by the absence of parietal protuberances, presence of weak parietal ridges, a faint sagittal crest, and a distinct transversely forked occipital horn (Patton and Taylor, 1973:fig.5). Paratoceras further differs from Protoceras in having smaller (relative to skull length) and more posteriorly located maxillary protuberances (relative to the position of the anterior root of P2); the supraorbital ossicones are taller (relative to their length), more gently recurved, and have distinctive flared and triangular basal segments and bulbous tips (Patton and

Taylor, 1973:fig.5). The orbits of Paratoceras are more anteriorly placed relative to the posterior root of M3, the facial region is shorter (relative to the skull length), and the premolars are shorter (relative to M1 or m1: APL) and more bulbous than those of

Protoceras. The crowns of the molars are higher relative to length and the lingual cinguli on P2-P3 are more reduced. The protocone on P3 is reduced in all dimensions compared to the other cusps and often represented exclusively by a small cuspule connected to the cingulum.

Paratoceras differs from Pseudoprotoceras in being larger, having maxillary and frontal protuberances on the male skull, having a narrow (relative to APL) P2 with no lingual cingulum and a reduced number of cusps, and upper molars with continuous lingual cingula. The lower premolars of Paratoceras have paraconids that are not anterolingually directed and lack the distinct anterolingually inflected metaconids of

Pseudoprotoceras (Emry and Storer, 1981).

Paratoceras tedfordi, the oldest member of the genus, was found in amber deposits of the late Oligocene-early Miocene Balumtum Sandstone (22-26 Ma) in southern Mexico (Webb et al., 2003). Recently published Sr/Sr dates (c. a. 20-23 Ma) for the underlying Mazantic Shale and the Mucuzpana Limestone (Vega et al., 2009) coupled with biostratigraphy of benthic and planktonic foraminifera (Solórzano-Kraemer,

2007; 2010) suggest a younger age (early Miocene) for the amber bearing sequences.

Unfortunately, the stratigraphic relationships of the main fossil bearing units in the

Simojovel area are still unclear (Solórzano-Kraemer, 2010).

Paratoceras aff. P. tedfordi

(Figs.2-2, 2-3, 2-4; Table 2-1)

Locality and horizon. Lirio Norte L. F. (site YPA024 in UF Vertebrate

Paleontology Collection), Panama Canal area, Panama, Central America. Fossils were collected in the upper part of the Las Cascadas Formation (Figure 2), equivalent to the late Arikareean Ar4 NALMA (Figure 1) (Rincón et al., 2012a,b).

Referred material. UF 244199, left P2; UF 271626, right P3; UF 271618, right P4;

UF 271620, left M2; UF 236931, left M2; UF 275168, left mandible with Lm2-m3; UF

267194, right mandible with Rp4-m3; UF 254119, right p4; UF 244213, right m1; UF

271627, right m2; UF 254121, left m2; UF 271179, left m2; UF 271622, left m2.

Description

Upper dentition. The P2 (Figure 2-2 A-B) is tri-rooted with the lingual root located close to the posterolabial root. The crown is elongate (APL > TW), lacks external ribs, and has a distinct paracone interrupting an internal cingulum, that widens posteriorly and which encloses a small open basin lingual to the metastyle. The parastyle, paracone and metastyle are aligned, forming a straight labial margin. The anterolingual

crescent is low and formed by a not very distinct small cingular segment. The posterolingual crescent is also low and formed by a distinct small cingular segment that extends lingually from the base of the paracone towards the posterior margin, but which never reaches the lingual part of the base of the metastyle.

The P3 (Figure 2-2 C-D) is also tri-rooted, but with a more lingually expanded crown at its midpoint (forming a more distinct “wedge-shape”) than that of P2. The crown of P3 further differs from that of P2 in having a distinctively higher and stronger paracone, a metastyle that is less distinct and slightly recurved labially, and an internal cingulum that is more nearly continuous and reaches the labial segments of both the parastyle and the mesostyle. The internal cingulum forms a narrow valley anterior to the labial surface of the paracone (Figure 2-2 C-D) and a wider valley on the surface posterior to the paracone. There is no evidence of a functional protocone, with only a basal widening of the lingual cingulum present on that part of the crown. The parastyle, paracone, and metastyle are aligned forming a straight labial margin with no labial projection of the metastyle.

The crown of P4 (Figure 2-2 E) is triangular (labial longer than lingual margin) and submolariform with the development of a crescent but lacking a metacone and hypocone. Its crescent is asymmetric with a shorter anterior crista that is responsible for an anteriorly placed protocone. The metastyle is distinct whereas the parastyle is only evident at the basal part of the crown. The internal cingulum is weak and interrupted by the lingual part of the protocone.

The crown of M2 is wider than it is long and has thick, crenulated enamel (Figure

2-2F). The parastyle is distinct and strong ribs extend up the anterior and posterior

crests from the base of the crown to the tip of both the paracone and metacone. The crests are parallel and there is no anterior overlap between them, resulting in the lack of a well-developed mesostyle, which is only partially represented by an apical extension of the basal cingular segment located labially between the crests. The shape of the crescents varies from an open (towards the labial margin) V for the posterior crescent to a more closed V for the anterior crescent. Crescents are asymmetric with relatively longer anterior cristae that are responsible for a wider (relative to APL) anterior

(compared to posterior) aspect of the crown. A strong continuous basal cingulum connects the anterior and posterior crests on the lingual margin of the crown and converges in an intercolumnar pillar at the labial opening of the transverse valley

(Figure 2-2 F).

Lower dentition. In UF 267194, the crown of p4 is elongate (APL>TW) and longer than that of m1 (Table 1-1). The anterior margin is formed by a narrow and abbreviated paraconid whereas the posterior margin is fashioned by a distinctive labial cuspulid at the base of the crown (Figure 2-3 A). It has a high protoconid and a low and straight paraconid. The metaconid and entoconid are present on the margins of a wide talonid.

The lower molars are brachydont, with deep anterior and posterior fossettids and crenulated thick enamel (Figure 2-3 A). Each molar has two discontinuous and overlapping crests with a distinctive metastylid. The metaconid crest is well separated from the rest of the tooth in early wear stages. The crescents are asymmetric with long anterior cristids that are responsible for the posteriorly positioned protoconid and hypoconid. A distinctive basal cingulid is present anterior to the protoconid (Figure 2-3

B) and connects the base of the parastylid with the labial margin of the anterior

crescent. The intercolumnar pillars are restricted to the basal part of the protoconid and hypoconid crests along the molar series (Figure 2-3 B). The parastylids are well developed and a strong and distinct entostylid is present on the m3 (Figure 2-3 C). Two enamel ridges divide the hypoconulid of m3 (Figure 2-3 A). The lingual ridge is broader than the labial ridge and encloses a distinct invagination restricted to the apical segment of the crown.

Discussion and Comparisons

Brachydont partial dentitions from the Lirio Norte L. F. are referred to the genus

Paratoceras Frick, 1937 based on the presence of a distinctive posteriorly wide and wedge-shaped p4, lack of a distinctive protocone on P2 and P3, and the absence of convex labial margins in the upper premolars, the lattermost being a distinctive morphology present in Protoceras celer and faintly noticeable in Protoceras skinneri

(Patton and Taylor, 1973). Although weaker than those present in P. wardi, the cingula on both the anterior and posterior part of the crescents on M2 are continuous, and closely resemble those of the holotype of Paratoceras tedfordi (Webb et al.,

2003:fig.14.3). This condition is in direct contrast to that of Protoceras,

Pseudoprotoceras, and Prosynthetoceras, which have less nearly continuous cingular segments that are more restricted to the anterior part of the crescents (Frick, 1937;

Patton and Taylor, 1973; Emry and Storer, 1981). The straight paraconid and elongate p4 of Paratoceras from the Lirio Norte L. F. are more similar to those of P. wardi (Figure

2-4) than those of P. coatesi sp. nov. from the younger Centenario Fauna (see below).

Paratoceras from the Lirio Norte L. F. has an approximate APLp4/APLm1 ratio of 1.10, whereas, P. wardi, P. orarius sp. nov and P. coatesi sp. nov have ratios of 1.02, 0.90, and 0.87, respectively (see below). While the distinctive strong parastylid (Figure 2-3C)

present on the lower molars from the Lirio Norte L.F. seems to be unique among species currently allocated to Paratoceras, I am reluctant to name a new species because the morphology of the upper dentition is so similar to that of P. tedfordi, for which the lower dentition is still unknown (Webb et al., 2003). My designation

(Paratoceras aff. P. tedfordi) is supported by the similar dimensions of the M2 (Figure 2-

5), the development of the protocone in P2 and P3; and shared morphologies of the cingular segments in the upper molars.

The morphology of the talonid of m3 is somewhat similar to that of floridatraguline camels recovered from the same locality (a divided hypoconulid where both the lingual and labial selenes are projections of the hypoconid and entoconid); however, protoceratines are characterized by the presence of wider lower molars with thick crenulated enamel, less reduced premolars, and a distinctive shallower invagination of the talonid of m3 which is only evident in unworn stages (Rincón et al., 2012a).

Paratoceras orarius sp. nov.

(Figure 2-6, Table 2-2, Appendix A)

= P. wardi Kirby, Jones, and MacFadden (2008).

Holotype. UF 271625, right partial mandible with p3-m3 (Figure 2-6).

Locality and horizon. UF 271625 was found in the Lirio Sector (YPA-063 in UF

Vertebrate Paleontology Collection, Panama Canal area (Figure 1-1); UF 237878, UF

280224 and UF 267081 were found in similar stratigraphic levels (YPA015, YPA084, and YPA016 respectively) along the upper part of the Culebra Formation (Figure 2-1) in the Lirio Sector. These lithostratigraphic levels are approximately equivalent to the levels containing specimens of “Cynorca” occidentale Woodburne, 1969 (MacFadden et

al., 2010:fig.2) and are correlative to the Section 3 of Kirby et al., (2008). These intervals are interpreted to represent the early Hemingfordian NALMA (He1) based of the occurrence of the rhinocerotids Menoceras barbouri Troxell, 1921 and Floridaceras whitei Wood, 1964 also reported by MacFadden (2006) and Kirby et al., 2008 (Tedford et al., 2004), and the independent age determinations provided by MacFadden et al.

(2014).

Etymology. ‘orarius’ from Greek: estuarine or coastal, referring to the inferred sedimentary environment represented by the upper Culebra Formation (Retallack and

Kirby, 2007), where the holotype was found.

Referred material. UF 237878, left partial mandible with m1-m3; UF 280223, right m1; and UF 267081, left m1.

Diagnosis. Smallest known protoceratine. Differs from all other species of

Paratoceras in having narrower lower cheek teeth, p3 lacking entostylid, anteriorly wedge-shaped p4 with straight paraconid; and p4 lacking metaconid, postero-labial cuspulid, and anterolingual flexid. Further differs from P. macadamsi in having more brachydont cheek teeth, and lacking anterolingual flexid on p3.

Description

Mandible. The holotype includes the posterior part of the horizontal ramus including the alveoli of p2 (Figure 2-6 A-C). The lingual and labial surfaces of the ramus are mostly uniform (subparallel) below the p4-m3 series but start to narrow (converge) anterior to p3 (Figure 2-6 B). In lateral view, the ventral margin of the anterior part of ramus forms an inflected convex margin centered below the p2 alveoli (Figure 2-6 B). A single anterior mental foramen is preserved in the mandible (UF 271625) beneath the posterior root of p3.

Lower dentition. The p3 is elongate (APL>TW) and double-rooted. Despite the fact that the protoconid is partially preserved in the only know specimen with a p3, the crown has a well-defined protoconid (Figure 2-6 A). The conical paraconid is separated from the high and pointed protoconid by a distinct notch but it lacks an anterolingual flexid. The talonid of p3 is simple with no evidence of entostylid or any crest associated with the protoconid. The crown of p4 is anteriorly wedge-shaped (with a posterior margin wider than the anterior margin) and remarkably shorter than that of p3 (Table 2-

2). Despite the fact that the crown has little wear, there is no evidence of a distinct metaconid. The crown has a straight and abbreviated paraconid, a high protoconid, and a transversely wide talonid. The talonid is narrow with a twinned junction of the hypoconid and entoconid forming the posterior-most aspect of the crown and aligned with the protoconid along the midline. There is no labial cuspulid on the posterior margin of the hypoconid of p4 (Figure 2-6 A).

The lower molars are brachydont with deep anterior and posterior fossettids

(Figure 2-6 A). The enamel is smooth and lacks strong crenulations. The molars have discontinuous and overlapping crests that appear to intersect after moderate wear. The crescents (hypoconid and protoconid) are asymmetric with anterior cristids longer than the posterior cristids. Intercolumnar tubercles are barely evident, and restricted to the basal parts of m1 and m2, but are absent on m3 (Figure 2-6 B). No cingulids are present on the labial margin of the lower molars and only a well-developed cingulid is visible on anterior margin of the protoconid (Figure 2-6 B). Despite their brachydont morphology, the molars are relatively narrower (m1 and m2 APL/TW ratio ~ 1.26) than those of the Barstovian P. wardi (m1 and m2 APL/TW ratio ~ 1.13), the Hemingfordian

P. coatesi sp. nov from the late Centenario Fauna (m1 and m2 APL/TW ratio ~ 1.10), but considerably similar to the proportions documented for the Clarendonian P. macadamsi (m1 and m2 APL/TW ratio ~ 1.24). The crowns have well-defined lingual ribs and stylids that are only noticeable in early wear stages and the metaconid and entoconid are disconnected in all but the most-advanced wear stages. The discontinuous and overlapping crests form a distinctive metastylid and the entostylid consists of a lingual projection of the posterior crescent. Intercolumnar tubercles are faintly developed and restricted to the basal part of the crown between the protoconid and hypoconid (Figure 2-6 B). Parastylids are well developed on each of the molars and a distinctive well-developed entostylid is present on the m3 (Figure 2-6 C). Two enamel ridges compose the hypoconulid of m3. The labial ridge is broader than the lingual and together they enclose a shallow fossetid (Figure 2-6 A).

Discussion and Comparisons

The strong paraconid on the elongate p3 and the straight paraconid on p4 of

Paratoceras orarius sp. nov are more similar to those of Paratoceras than other early

Miocene protoceratids (e. g. synthetoceratines). The shallowest point of the mandible of

Paratoceras orarius is located below the p3 alveoli in similar to that of taxa classified in

Protoceratinae. In synthetoceratines this mandibular hallmark is located approximately on the mid-point of a distinctive longer p1-p2 diastema (Patton and Taylor, 1971).

The molar dimensions of Paratoceras orarius (Figs. 2-4, 2-5) are the smallest among known protoceratines. The ratios of the length of the p3 and p4 relative to the length of the m1 in the holotype indicate that P. orarius has an unreduced p3. This hallmark is also present in Paratoceras (Frick, 1937:608; Patton and Taylor, 1973) but absent in Synthetoceratinae, which are characterized by more reduced lower premolars

with shorter paraconids (Patton and Taylor, 1971). Paratoceras orarius sp. nov from the early Centenario Fauna is characterized by a narrower lower dentition (Figure 2-5,

Table 2-2) with an approximate APLp4/APLm1 ratio of 0.90, whereas, P. wardi, P. aff. tedfordi from the Lirio Norte L. F., P. coatesi sp. nov, and P. macadamsi have approximate ratios of 1.02, 1.10; 0.87, and 0.93, respectively.

The lower premolars of P. orarius lack the anterolingually directed strong metaconids of Pseudoprotoceras (Patton and Taylor, 1973; Emry and Storer, 1981) and the stronger and more inflected paraconids of P. wardi. However, the bulbous paraconids of P. orarius are more similar to those present in the premolars of the

Clarendonian P. macadamsi (Patton and Taylor, 1973:Figure13E). Although exhibiting an overall narrower lower dentition (m1 and m2 APL/TW ratio ~ 1.26), the general morphology of the hypoconulid of the m3 is similar to that of the Barstovian P. wardi and the Arikareean Paratoceras cf. P. tedfordi from the Lirio Norte L. F. The general morphology of the lower dentition of the small bodied P. orarius is similar to that of the larger bodied Clarendonian P. macadamsi; however, this late Miocene higher-crowned protoceratine is characterized by having an elongate p4 with a lingually inflected paraconid and a p3 with strong anterolingual flexid and parallel posterior crests that are anteroposteriorly oriented (Patton and Taylor, 1973:Figure 13).

Paratoceras coatesi sp. nov.

(Figs. 2-7, 2-8. 2-9; Table 2-3, Appendix A)

Protoceratidae: Whitmore and Stewart (1965:182).

Paratoceras, ?new species: Patton and Taylor (1973:368).

Paratoceras wardi: MacFadden (2006:726).

P. wardi Kirby, Jones, and MacFadden (2008:6).

Holotype. UF 223585, incomplete skull that includes partial maxillae with right P4-

M3 and left M1-M3, complete nasals, and partial frontal and supraorbital horns.

Locality and horizon. Escobar Hill (site key YPA-003 in UF Vertebrate

Paleontology Collection), Gaillard Cut, Panama Canal area, Panama, Central America

(Figure 1-1 A). The holotype was collected by M. X. Kirby in 2004 (but not previously figured or described) from the same uppermost fossiliferous horizons of the Cucaracha

Formation (Figure 2-1 B) that yielded the Centenario Fauna (MacFadden et al.,

2010:fig.2; Section 8 of Kirby et al., 2008:fig.6). These horizons are correlated to the early Hemingfordian NALMA (He1) (MacFadden et al. 2014).

Etymology. Named in honor of Dr. Anthony G. Coates, Staff Scientist (Emeritus) at the Smithsonian Tropical Research Institute, for his many contributions towards a better understanding of the geology of southern Central America and the timing and consequences of the rise of the Isthmus of Panama.

Paratype. UF 271182, left dentary with p1, p3-m3; right dentary with p1, p3-m3; and symphysis with anterior alveoli. Paratype was recovered from the Centenario 2 locality (site key YPA060 in UF Vertebrate Paleontology Collection) corresponding to the upper part of the Cucaracha Formation (Figure 2-1).

Referred material. UF 237854, left mandible with Lm1-m3 (Escobar Hill;

YPA003); UF 271624, right mandible with Rp3-m3 (Hodges Hill; YPA026); UF 223094

(Cast of SMU 68102), left mandible with Lp4-m3 (Lirio Area; YPA002); UF 267124, left mandible with Lp4-m3 (Hodges Hill; YPA026); UF 267123, left mandible with Lp2-m3 and partial symphysis (Hodges Hill; YPA026); UF 223328 (Cast of USNM 23154), right mandible with Rp3-m3; UF 271181, right mandible with Rp1-m2 and partial symphysis

(Hodges Hill; YPA026); UF 267125, left mandible with Lp4 and partial Lm1-m2

(Centenario Bridge; YPA009); UF 280222, right mandible with Rp3-m2 (Centenario 2;

YPA060); UF 223326 (Cast of USNM 23165), partial left maxilla with LM1-M3 (Lirio

Area; YPA002); UF 236917, right M3 (Cartagena Hill; YPA008); UF 236913, partial right maxilla with RP3 (broken), and Rp4-M1 (Centenario Bridge; YPA009); UF 223584, partial left maxilla with LP3-M1 (Escobar Hill; YPA003); UF 280221, right M3

(Centenario Bridge 2; YPA060); UF 237877, partial right maxilla with RP2-M3

(Centenario Bridge; YPA009); UF 271180; left partial maxilla with LP4-M3 (Centenario

2; YPA060); UF 237862, left M1 (Centenario Bridge; YPA009).

Diagnosis. Differs from all other species of Paratoceras in having relatively wider lower premolars with bulbous paraconids; and p3 lacking an anterolingual flexid. Further differs from P. wardi in having weaker antero-lingual cingular segments on upper premolars, a relatively shorter p4; males have longer nasals, more delicate and low supraorbital ossicones, and more elevated preorbital protuberances. Further differs from

P. tedfordi in having a relatively narrower P4 and relatively shorter P2-M3 series (~12 % shorter). Further differs from P. orarius in having larger teeth, deeper mandible anterior to p3, and relatively wider lower molars. Further differs from P. macadamsi in having more brachydont dentition, shallower mandible, p3 with straighter and weaker paraconid.

Description

Skull. Substantial deformation anterior to the orbits in the partial skull (UF 223585) has artificially reduced the distance between the frontals and maxillae in lateral views

(Figure 2-7). The frontals, which have an anterior contact with the nasals, are large and wide massive bones (Figure 2-7 A-B). The partially preserved supraorbital ossicones

are composed exclusively by a prolongation of the frontal bones. The anteroposterior length of the base of the ossicone at the level of the roof of the orbit is 31.0 mm and it rises to a height of approximately 50.0 mm above the base (Length/Height Ratio:

~0.62). The proximal (basal) segment of each ossicone is flared (Figure 2-7 A-C) whereas the partially preserved distal aspect is characterized by a tapering and blunted triangular morphology. The supraorbital ossicones, although partially deformed, are gently medially recurved and narrow gradually from the base up to the posteriorly recurved distal end. The dorsal surface of the frontal is rugose with deep grooves, pits, and numerous small foramina (Figure 2-7 B). Similar rugosity is also present on the dorsal surface of the nasal and maxillary bones. The suture of the frontals forms a low but distinctive sagittal ridge that ends at the naso-frontal suture. From this point, a small ridge extends laterally to form a longitudinal deep pit anterior to a large and distinct fossa located in the posterior part of the nasal bone. This pit extends from the posteromedial end of the nasal to the anteromedial end of the second conical pair of maxillary protuberances located above the M2 (Figure 2-7 A-B). These tuberosities at the lateral junction (left and right) of the frontal and nasal resemble a distinctive pair of small ossicones (Figs. 2-7 A, E-F). The sutures surrounding the nasals are clearly distinct. The nasals contact the dorsal margin of the maxillae for most of their length (~

52 mm on the median line), ending anteriorly at the level of P3 with short anterior wedge-like projections that join at the midline (Figure 2-7 B). The nasals widen posteriorly, with their widest point at the contacts with the lacrimals. The dorsal surface of the nasals has two deep longitudinal grooves that lead posteriorly to supra-orbital foramina in the frontals. While the suture with the zygomatic is not preserved, a

descending process from the frontal partially closes the orbit posteriorly (Figure 2-7 E-

F). In lateral view, the anterior part of the lacrimal contacts the maxilla ventrally and the nasal and frontal dorsally, and the posterior lacrimal contacts the frontal forming a conical protuberance (Figure 2-7 E-F). Three lacrimal foramina are located within the orbital anterior border. The palatine bones are flat and narrow (Figure 2-7 D), and are anteriorly bounded by the maxillary bones. In ventral view, the suture between the palatine bones and the maxillary bones is at the level of the roots of M1 (Figure 2-7 D).

The maxillary-palatine suture projects from the midline labially and curves posteriorly as it approaches the posterior root of M2. In ventral view, a reduced palatine bone surrounds the internal nares. The palatine bones are restricted to a thin rim of the choanal border and their suture with the maxillary bones extends forward from the lingual part of the M3 alveoli, reaching the maxillary suture lingual to M2. The anterior end of the internal nares in the palate is located at the level of the posterior root of M2.

The orbits are large, suboval in outline, and widely separated from each other. The anterior margin of the orbit is above the M3. The roof of the orbit gives rise to the supraorbital ossicones (Figure 2-7 E-F).

The partially preserved anterior ossicones are formed entirely by an expansion of the maxillary bones. They project above P4 and seem to be located behind the anterior end of the nasals (Figure 2-7 A, E-F). A strong lateral ridge is partially preserved in the right maxilla (Figure 2-7 F). This ridge roughly starts above P4, forming a prominent tubercle and continuing posteriorly to the anterior margin of the orbit. The posterior narial notch is posterior to the palato-maxillary suture and is located between the palatine and the pterygoid. The maxillary plates form the roof of the palate.

Upper dentition. The crowns of P2, P3 and P4 are better preserved in UF 237877

(Figure 2-8) than in the holotype (UF 223585) and form the basis for much of the description here. The P2 is tri-rooted with the lingual root located close to the posterolabial root. The crown is elongate (APL > TW), lacks external ribs, and has a distinct paracone interrupting an internal cingulum (Figure 2-8 A). This cingulum widens posteriorly and encloses a small open basin lingual to the metastyle. The labial margin of the crown is straight with the parastyle, paracone and metastyle anteroposteriorly aligned. The anterolingual crescent is low and formed by a distinct small cingular segment. The posterolingual crescent is also low and formed by a small cingular segment that extends lingually from the base of the paracone towards the posterior margin of the crown.

The crown of P3 resembles that of P2 in general morphology. The P3 (Figure 2-8

A) is also tri-rooted, but with a more lingually expanded crown posterior to its midpoint

(forming a more distinct “wedge-shape”) than that of P2. The crown of P3 further differs from that of P2 in having a distinctively higher and stronger paracone, a less distinct metastyle that is slightly recurved labially, and an internal cingulum that is more nearly continuous and reaches the labial segments of both the parastyle and the mesostyle.

The internal cingulum forms a narrow valley anterior to the lingual surface of the paracone (Figure 2-8 A-C) and a wider valley on the posterior margin of the paracone.

While the labial contour of the crown is straight (the parastyle, paracone and metastyle are aligned), the lingual cingular segment is simple with no evidence of a functional protocone.

The crown of P4 (Figure 2-8 A) is triangular (labial longer than lingual margin) and submolariform with the development of a crescent but lacking a metacone and hypocone. The metastyle is more prominent and more labially recurved than the parastyle. The crescent is asymmetric with a shorter anterior crista that is responsible for a forwardly placed protocone. The internal cingulum varies from a continuous well- developed basal cingulum, to basal cingular segments that are not continuous, and are restricted to the anterior and posterior labial portions of the crescents. The upper molars are wider than they are long and have crenulated enamel (Table 2-3; Figure 2-5). The

M1 and M2 have strong stylar cusps on the anterior and posterior crests. The internal cingulum of the upper molars is similar in its variable continuity to that of P4. For example, the holotype (UF 223585) has a strong continuous cingulum along the anterior and posterior margins of each upper molar. It projects from just above the base of the crown and extends along the anterior or posterior basal part of each crescent. On the other hand, these internal cingula are not continuous in UF 237877, but interrupted by the protocone and metaconule. The crowns of M1 and M2 are rectangular (transversely elongated) in occlusal outline, while M3 has a more squared outline with a transversely reduced posterior margin (Figure 2-8 A). Both M1 and M2 have prominent mesostyles and strong ribs extending up each crest from the base of the crown to the tip of both the paracone and metacone (Figure 2-8 C). The shape of the crescents varies from an open V or U (towards the labial margin) in the posterior molars to a more closed V on

M1. The crescents of M1 and M2 are asymmetric with relatively shorter anterior cristae that are responsible for a more forwardly placed protocone and metaconule (Figure 2-8

A). In UF 237877, the crests of M3 (paracone and metacone) are aligned and are more

or less continuous, resulting in the absence of a mesostyle; whereas in the holotype (UF

223585), the mesostyle is well developed (Figures. 2-7 D, 2-8 A). However, in both specimens the anterior crescent of the crown of M3 is remarkably wider than the posterior one, which is extremely reduced transversely.

Mandible. Well-preserved and associated left and right dentaries are described here and included as a paratype (UF 271182) of Paratoceras coatesi. The horizontal ramus is slender and gradually shallows anterior to m1 in lateral view (Figure 2-9).

While the lingual and labial surfaces of the ramus are uniform below the p4-m3 series, the mandible is ventrally recurved anterior to p3 and flares labially anterior to p2 in occlusal view (Figure 2-9 A-B). The p1 is separated from the incisors by an anterior diastema that appears to be short but the exact length is unknown because of poor preservation in that region. The crown of p1 is further separated posteriorly from that of p2 by what appears to be a longer diastema subequal to the length of the p3 (Figure 2-9

D). The dorsal edges of the p1-p2 diastema are sharp and pinched below the edge forming a well-defined crest. The mandibular symphysis is unfused, oval, short and deep with a distinct ventral projection beneath p1 (Figure 2-9 D-F). Two small mental foramina are present, one beneath the posterior alveolus of p3 and the other beneath the p1-p2 diastema (Figure 2-9 D).

Lower dentition. In none of the specimens are the incisors or their alveoli anterior to p1 preserved. The first premolar is caniniform, single rooted, and posteriorly recurved

(Figure 2-9 A-B). Both the lingual and labial surfaces are convex and lack crenulations or additional cusps. The crown is distally elongate with a small ridge on the basal posterior part of the crown that extends to the apical posterior tip and an anterior ridge

that extends up the anterior edge of the crown interrupted by a moderately developed wear facet for about half its length (Figure 2-9 B). Dentine is exposed on the occlusal wear surface as a narrow band on the anterior margin of the enamel. Although severely affected by deformation and wear, the only p2 available for description is that reported in UF 271181 (see referred specimens). The p2 is double rooted and subequal to the length of the p3 (Appendix A). The crown is elongate (APL>TW) with a distinct paraconid separated from the protoconid by a notch. In all general morphologies preserved, the p2 is comparable to the p3 of the paratype (Figure 2-9 C), differing only from the latter in having a narrower talonid.

The p3 is elongate and has a distinctive bulbous and more robust crown than that of the p2 (Figure 2-9 C). It is double-rooted with an abbreviated paraconid, an acute apex (metaconid), and a more developed talonid than that of p2. The paraconid is separated from a high and conical protoconid by a distinct notch with no evidence of an anterolingual flexid. The talonid makes up about one-third of the crown of p3 and forms a distinctive open valley with a distinct entoconid and entostylid on its lingual margin. In occlusal view the crown of p4 is anteriorly wedge-shaped. The posterior segment

(talonid) is wider than the anterior segment and fashioned by a labial cuspulid. The paraconid of p4 is narrow, lingually inflected, and forms a lingual anteroflexid. The metaconid, only evident in early wear stages, is situated high on the crown and close to the protoconid, resulting in a relatively short, high-crowned and bulbous tooth (Figure 2-

9 C). The entoconid and entostylid are located on small crests that project parallel to each other, forming a posterolingually open valley. This valley is present in early wear stages, but with progressive wear the talonid becomes a narrow crest directed

posteriorly. The lower molars are brachydont, weakly crenulated, and have well- developed anterior and posterior fossettids. The crests of the metaconid and entoconid are not connected, and the posterior end of the metaconid overlaps the anterior end of the entoconid (Figure 2-9 A-C). The parastylid is formed by the lingual expression of the anterolingual cristid of the paraconid, but this morphology is only evident in the early stages of wear. Parastylids are slightly developed in m1 and m2 and barely discernible on the anterior crest of m3. Intercolumnar pillars are restricted to the basal part of the labial aspect of the crown between the protoconid and hypoconid on m1 and m2 and are variably present on m3 (Figure 2-9 D-E). A distinctive entostylid is present in the lingual surface of m3 (Figure 2-9 C). Two ridges divide the hypoconulid of m3 forming a double enamel loop on the talonid of m3, which encloses a fossetid (Figure 2-9 A-B).

Discussion and Comparisons

While the diagnostic occipital forked ossicone found in male specimens of

Paratoceras is not preserved in the holotype of P. coatesi, many informative characters are otherwise evident. The skull of Paratoceras coatesi has a number of diagnostic protoceratine characteristics that are also present in the male skull of P. wardi from the

Barstovian Trinity River L. F. in Texas but absent in Protoceras. These include: (1) flared supraorbital horns that are triangular in cross section with a rugose anterior edge;

(2) more forwardly placed orbits than those of Protoceras and Pseudoprotoceras; (3) maxillary protuberances that arise more posteriorly than those of Protoceras; and (4) nasals retracted to the level of P3. The dentition resembles that of P. wardi in having:

(1) upper molars that are wider than longer; (2) variable expression of the internal cingula (from strong and continuous to weak and discontinuous) on the upper molars;

(3) lack of a distinctive protocone on P2 and P3; and (4) the labial surface of P2 and P3

straight with no evidence of the labially projected parastyle that is present in Protoceras and Pseudoprotoceras.

In contrast to Paratoceras wardi, the more gracile morphology of the supraorbital ossicones of Paratoceras coatesi and the second and stronger conical pair of maxillary protuberances above the lacrimals are the most distinctive hallmarks preserved in the partial male skull. P. coatesi differs from P. wardi in having weaker antero-lingual cingular segments on upper premolars, more bulbous (relatively wider and shorter) lower premolars (Figure2-4; Table 2-3), a p3 lacking an anterolingual flexid between the paraconid and the protoconid, more delicate supraorbital horns (Length/Height Ratio for

P. coatesi is ~0.62 vs. ~0.70 for P. wardi), longer nasals (NasalMedianLength/APLM1-

M3 Ratio for P. coatesi is ~1.32 vs. ~0.94 for P. wardi), and more pronounced conical protuberances at the lateral junctions of the frontal and nasal in males (Patton and

Taylor, 1973:Figure5; table 4). P. coatesi (male) has longer nasal bones than those of the holotype of P. tedfordi (female) as was previously noticed for Protoceras (Marsh,

1897). Although only known from a female upper dentition, the P4 of Paratoceras tedfordi is wider than the M1 (Webb et al., 2003:table 14.1) whereas, in P. coatesi, the

P4 is narrower than the M1 (Figure 2-5). While the general morphology of the crown of the p4 and the lower molars of P. coatesi are similar to that of P. macadamsi, it lacks the higher crowns and deeper mandible characteristic of the larger Clarendonian protoceratine. Paratoceras coatesi sp. nov from the Centenario Fauna has an approximate APLp4/APLm1 ratio of 0.87, whereas, P. wardi, P. orarius sp. nov, P. aff. tedfordi (Lirio Norte L. F.), and P. macadamsi have ratios of 1.02, 0.90, 1.10, and 0.93, respectively.

The general morphology of the cingula on the upper dentition and the development of a mesostyle on the upper M3 of Paratoceras coatesi are variable. The cinguli vary from more nearly continuous around the P4-M3 series in the holotype

(Figure 2-8) to discontinuous cingular segments, more restricted to the lingual opening of the transverse valley in the referred specimens and are interrupted by the protocone and the metaconule. However, the postero-lingual cingular segments are predominantly more developed than the anterior counterparts in the upper premolars (P2-P3). The morphology of the M3 metastyle is also variable in specimens with comparable tooth dimensions in the P. coatesi specimens. Besides its distinctively wider and bulbous lower premolars and a P4 that is narrower than the M1, P. coatesi is most similar to P. tedfordi in all other comparable morphologies preserved in the holotype of P. tedfordi.

Phylogenetic Analysis

To evaluate the phylogenetic relationships of the new fossil species from Panama

I performed a cladistic analysis of 10 protoceratine taxa with the primitive protoceratid

Heteromeryx dispar from the Chadronian of Texas and the Great Plains as the outgroup

(Figure 2-10, Appendix C). Because most protoceratid species are not known from large samples of fossils that preserve cranial morphology, mainly dental (12) and only a few cranial (3) characteristics that presumably do not exhibit a marked sexual dimorphism

(Appendix B) were scored and used in my analysis. Morphologic data were compiled from a study of specimens and a literature review. The data matrix (Appendix C) includes characters that are unordered and weighted equally and characters not known for a taxon were coded as missing. Data were compiled in Mesquite version 2.72

(Maddison and Maddison, 2009) and then analyzed under the parsimony criterion using the branch and bound algorithm of PAUP version 4.0b10 (Swofford, 2003). The analysis

resulted in a single equally-most parsimonius cladogram (MPT) with a tree length of 24 steps, a consistency index (CI) of 0.875, a retention index (RI) of 0.889, and a homoplasy index (HI) of 0.125 (Figure 2-10).

My results support a monophyletic Paratoceras (node 4), based on the presence of strongly retracted nasals (1[1]); P3 protocone reduced to a basal cingular segment interrupted by an inflated paracone (3[2]); orbits located anterior to the posterior roots of the M3 (6[1]); and a P3 with a straight labial margin lacking enlarged labial styles

(12[1]). The Arikareean P. tedfordi from southern Mexico appears as the most primitive species of the genus.

In the resulting topology, Paratoceras aff. P. tedfordi from the Lirio Norte L. F. appears as the sister taxon of the Hemingfordian, Barstovian and Clarendonian

Paratoceras spp. These relationships are based exclusively on the presence of relatively wider upper molars of this taxon (node 5, 2[1]). While new fossil discoveries are needed from low latitudes, the current distribution suggests that P. tedfordi could represent the ancestral stock that gave rise to the protoceratine radiation in tropical

Central America. The remaining spp. of Paratoceras with tropical and subtropical distributions include the Hemingfordian P. orarius and P. coatesi from Panama, and the

Clarendonian P. macadamsi and the Barstovian P. wardi from Texas (node 6) sharing a reduced p4 protoconid that forms a narrow valley with the hypoconulid (7[2]); relatively wider p4 (8[1]); m1 that is longer than p4, APLm1/APLp4 ratio > 1 (10[1]); and hypoconid reaching the metaconid on p3 (14[1]).

Within Paratoceras, the Hemingfordian forms from Panama, P. orarius and P. coatesi, are grouped with the Clarendonian P. macadamsi (node 7), based on the lack

of a strong parastylid on the lower molars (9[1]), and the more reduced p4 talonid with a shallow fossetid (13[2]). In this aspect, the Barstovian P. wardi and the late Arikareean

P. aff. tedfordi from the Lirio Norte L. F. are excluded in part based on having a longer p4, a morphological feature shared with Protoceras and the remaining members of the genus (node 2, (13[1])). The late Oligocene-early Miocene Protoceras appears as the sister taxon of Paratoceras tedfordi (node 2) based on the presence of a lateral ridge extending from the outer face of the maxillary bone to the orbit (5[1] DELTRAN); reduced p4 talonid with divergent entoconid and divergent entostylid (13[1]); reduced p4 protoconid forming an open valley with the hypoconid (7[1]); and presence of a paraconid on p3 (15[1]). The late Oligocene Protoceras celer forms a clade with similarly aged (Arikareean) Protoceras neatodelpha (node 3) based on the presence of anterolingual cingula on the upper molars (4[1]) and the presence of weak parastylids on the lower molars (9[1]).

Discussion

The early Miocene fossil record of Panama includes three species of protoceratines, all classified in the genus Paratoceras. Protoceratine fossils from the late Arikareean Lirio Norte L. F. are referred to Paratoceras aff. P. tedfordi based on the morphological characteristics of the upper dentition shared with that early Miocene species from Mexico. The small protoceratid Paratoceras orarius (initially reported as P. wardi, Kirby et al., 2008:fig. 6) is restricted to the lowermost stratigraphic levels of the

Centenario Fauna and was found in sedimentary sequences believed to represent deltaic (delta front) and transitional environments (Upper Culebra Formation). The medium sized P. coatesi (previously referred to P. wardi by MacFadden, 2006) is the most common ungulate recovered from the late Centenario Fauna. These stratigraphic

levels of the upper Cucaracha Formation may have represented more proximal deltaic plains (Kirby et al., 2008, Montes et al., 2012).

Results of a cladistics analysis of 11 protoceratine species, using 15 craniodental characters suggest that Paratoceras is closely related to the Oligocene to early Miocene genus Protoceras with early Miocene Paratoceras tedfordi from the Arikareean NALMA of Mexico and likely Panama (P. aff. tedfordi) as the basal members of the genus. The geographic distribution of species classified in the monophyletic Paratoceras clade is consistent with the idea that the group as a whole was endemic to subtropical and tropical areas of the Gulf Coast, Mexico, and Panama and became an abundant component of ungulate faunas from southern Central America by the Hemingfordian after colonizing recently emerged volcanic terrains connected to the Gulf Coast during the Arikareean. Paratoceras persisted in the tropical forests of Panama (Graham,

1999a) during the early Miocene (Hemingfordian NALMA), reaching the more temperate forest of Texas by the Barstovian NALMA (Patton and Taylor, 1973). By the late

Miocene (Clarendonian NALMA), Paratoceras macadamsi had evolved a more wedge- shaped p4, more reduced premolars, deeper mandible, and a more hypsodont dentition; these are all characteristics that are also found in synthetoceratine protoceratids (which are unknown south of Mexico; Webb, 2003). While it is certainly possible that these dental innovations (and inferred dietary specializations) are related to paleocological changes in the Gulf Coast during the late Miocene, testing this hypothesis would require detailed dietary, isotopic, and phytogeographic studies that are beyond the scope of this project.

The only species of Paratoceras known from male skulls are P. coatesi and P. wardi. While far from resolved given the paucity of data, morphological characters present in the male skull of P. coatesi (longer nasal bones and the more gracile morphology of the supraorbital ossicones than those of P. wardi) are intermediate between those of late Oligocene-early Miocene Protoceras celer and Barstovian

Paratoceras wardi from Texas. In a temporal preliminary framework, this morphological interpretation is consistent with a Hemingfordian age (He1) for the Centenario Fauna

(Tedford et al., 2004; MacFadden, 2006; MacFadden et al. 2014).

Webb et al., (2003) suggested that P. tedfordi from Mexico is late Oligocene-early

Miocene in age, but a younger proposed age (Vega et al., 2009; Solórzano-Kraemer,

2007; 2010) could account for the similarities to P. aff. P. tedfordi from the late

Arikareean Lirio Norte L. F. documented here. The new protoceratines from the

Hemingfordian Centenario Fauna (Paratoceras orarius and P. coatesi) share a distinctive p4 morphology (relatively wider and shorter crown) not present in either

Barstovian P. wardi or Arikareean P. aff. P. tedfordi but present in the Clarendonian P. macadamsi. While this conclusion is tentative, especially with the lower dentition of P. tedfordi still unknown, I suggest the possibility that allopatric speciation of Paratoceras in different paleobiogeographic provinces (e. g. tropical vs. subtropical) may have occurred in Central America.

Figure 2-1. Location and biochronology of the protoceratine-bearing fossil faunas discussed in this study. A, Pseudoprotoceras semicinctus from the Chadronian Cypress Hill Formation in Saskatchewan, Canada and the White River Formation of Wyoming (Emry and Storer, 1981); B, Pseudoprotoceras taylori from the late Chadronian White River Formation in Wyoming (Emry and Storer, 1981); C, Protoceras neatodelpha from the late Arikareean of Niobrara County, Wyoming (Patton and Taylor, 1973); D, Protoceras skinneri from the Gering Formation (early Arikareean) of South Dakota and Nebraska; E, Protoceras celer from the Whitneyan Protoceras channels, White River, South Dakota (Patton and Taylor, 1973); F, Pseudoprotoceras longinaris from the Chadronian of Wyoming and Nebraska (Cook, 1934); G, Paratoceras tedfordi from the late Oligocene- early Miocene Balumtum Sandstone in the Simojovel area, southern Mexico (Webb et al., 2003); H, Paratoceras wardi from the Barstovian Trinity River L. F. in Texas (Patton and Taylor, 1973); I, Paratoceras macadamsi from the Clarendonian Clarendon Fauna of Texas (Patton and Taylor, 1973); J, Paratoceras spp. (this study) from the late Arikareean Lirio Norte L. F. and the Hemingfordian Centenario Fauna from the Panama Canal Area (Rincón et al., 2012a,b; 2013; MacFadden et al., 2010). Chronostratigraphy and biochronology modified from Albright et al. (2008). Abbreviations: Ar, Arikareean NALMA; Ba, Barstovian NALMA; Cl, Clarendonian NALMA; E, early; He, Hemingfordian NALMA; L, late; L. F., Local Fauna; Pa., Paratoceras; Pr., Protoceras; Ps., Pseudoprotoceras.

Figure 2-2. Upper dentition of Paratoceras aff. P tedfordi from the late Arikareean Lirio Norte L. F. A, UF 244199, left P2, occlusal view; B, UF 244199, lingual view; C, UF 271626, right P3, occlusal view; D, UF 271626, right P3, lingual view; E, UF 271618, right P4, occlusal view; F, UF 236931, left M2, occlusal view. Abbreviations: Mst, Metastyle; Pa, Paracone; Pst, Parastyle. Arrows point anterolingually.

Figure 2-3. Lower dentition of Paratoceras aff. P. tedfordi from the Lirio Norte L. F. UF 267194, partial left mandible with p4-m3. A, occlusal view; B, labial view; C, lingual. Abbreviations: alcd, anterolingual cingulid; etsd, entostylid; hyd, hypoconid; ip, intercolumnar pillar; msd, metastylid; psd, parastylid. Arrows point anterolingually.

Figure 2-4. Bivariate plots of the natural logarithm of the anterior-posterior length versus maximum transverse width of the lower p4 for relevant specimens of Protoceratidae and their biostratigraphic distribution. Abbreviations: APL, anteroposterior length; Ar, Arikareean NALMA; Ba, Barstovian NALMA; Ch, Chadronian NALMA; Cl, Clarendonian NALMA; Du, Duchesnean NALMA; He, Hemingfordian NALMA; TW, transverse width; Ui, Uintan NALMA; Wh, Whitneyan NALMA.

Figure 2-5. Natural log-ratio diagram for dental measurements of Paratoceras spp. using Protoceras celer as a standard for comparison (straight line at zero). Abbreviations: APL, anteroposterior length; TW, transverse width.

Figure 2-6. Lower dentition of Paratoceras orarius sp. nov. from the upper Culebra Formation, UF 271625 (holotype), partial dentary with left p3-m3, left c1. A, occlusal view; B, labial view; C, lingual view. Abbreviations: esd, entostylid; etd, entoconid; hyd, hypoconid; ip, intercolumnar pillar; mf, mental foramen; msd, metastylid; pcd, paraconid; psd, parastylid.

Figure 2-7. Male partial skull of Paratoceras coatesi with right P4-M3 and left M1-M3, UF 223585 (holotype). A, right oblique view; B, dorsal view; C, anterior view; D, ventral view; E, left lateral view; F, right lateral view. Abbreviations: Aft, anterofrontal tuberosity; Fns, frontonasal suture; MaxOs, maxillary ossicone; Pms, palatomaxillary suture; Soc, supraorbital ossicone.

Figure 2-8. Detailed photographs of upper dentition of Paratoceras coatesi. A, UF 237877, right maxilla with P2-M3, occlusal view; B, labial view; C, lingual view. Abbreviations: Io: Infraorbital foramen; Mst, metastyle; Pa, Paracone; Plgc, posterolingual cingulum.

Figure 2-9. Lower dentition of Paratoceras coatesi, UF 271182 (paratype), paired mandibles with Rp1; Rp3-m3; Lp1; Lp3-m3 and symphysis. A, left dentary with p1, p3-m3, and partial mandibular symphysis, occlusal view; B, right dentary with p1, p3-m3, and partial mandibular symphysis, occlusal view; C, detail of Lp3-m1, occlusal view; D, right mandible with p1, p3-m3, labial view; E, left mandible with p1, p3-m3, labial view; F, right mandible with p1, p3-m3, lingual view. Abbreviations: esd, entostylid; etd, entoconid; hyd, hypoconid; ip, intercolumnar pillar; mf, mental foramen; pcd, paraconid.

Figure 2-10. Hypothetical relationships of the early Miocene protoceratines from Panama within protoceratinae based on a 15 character matrix with Heteromeryx dispar as the outgroup. A, Strict consensus tree resulted after the analysis under the parsimony criterion using the branch and bound algorithm of PAUP version 4.0b10 (Swofford, 2003) (Tree length = 24; CI = 0.875, RI = 0.885, HI = 0.125); B, biostratigraphic distribution of the protocratids included in the phylogenetic analysis. Abbreviations: Ar, Arikareean NALMA; Ba, Barstovian NALMA; Ch, Chadronian NALMA; Cl, Clarendonian NALMA; Du, Duchesnean NALMA; He, Hemingfordian NALMA; Or, Orellan NALMA; Ui, Uintan NALMA; Wh, Whitneyan NALMA. At each node (bold numbers) the supporting unambiguous synapomorphies are: 1, Protoceratinae (?) (4[2]); 2, (5[1] DELTRAN, 7[1], 13[1], 15[1]); 3, Protoceras (4[1], 9[1]); 4, Paratoceras (1[1], 3[2], 12[1], 6[1]); 5, (2[1]); 6, (7[2], 8[1], 10[1], 14[1]); 7, (9[1], 13[2]).

Table 2-1. Summary table of dental measurements (in mm) of Paratoceras aff. P. tedfordi from the Las Cascadas Formation. Abbreviations: APL, anterior-posterior length; TW, transverse width; TWhyd, hypoconulid transverse width; S, standard deviation; V, index of Variance. Paratoceras aff. P. tedfordi Lower Molars

Tooth Position N Range Mean S V

p4 (APL) 2 10.54-11.60 11.07 0.44 3.97

p4 (TW) 2 6.50-7.01 6.76 0.36 5.32

m1 (APL) 1 10.55 10.55 - -

m1 (TW) 1 9.24 9.24 - -

m2 (APL) 5 12.12-14.60 13.53 1.27 9.38

m2 (TW) 5 10.2-11.27 10.9 0.32 2.98

m3 (APL) 2 18.12-21.08 19.6 2.09 10.66

m3 (TW) 2 10.40-10.67 10.54 0.19 1.88

m3 (TWhyd) 2 6.56-6.85 6.70 0.20 3.05

Table 2-1. Continued. Paratoceras aff. P. tedfordi Upper Molars

Tooth Position N Range Mean S V

P2 (APL) 1 10.54 10.54 - -

P2 (TW) 1 6.01 6.01 - -

P3 (APL) 1 10.43 10.43 - -

P3 (TW) 1 6.11 6.11 - -

P4 (APL) 1 8.78 8.78 - -

P4 (TW) 1 11.01 11.01 - -

M2 (APL) 1 13.03 13.03 - -

M2 (TW) 1 16.68 16.68 - -

Table 2-2. Summary table of dental measurements (in mm) of Paratoceras orarius sp. nov from the upper Culebra Formation. Abbreviations: APL, anterior-posterior length; TW, transverse width; TWhyd, hypoconulid transverse width; S, Standard deviation; V, index of Variance. P. orarius sp. nov. Lower Molars

Tooth Position N Range Mean S V

p3 (APL) 1 10.73 10.73 - -

p3 (TW) 1 4.27 4.27 - -

p4 (APL) 1 8.45 8.45 - -

p4 (TW) 1 5.37 8.45 - -

m1 (APL) 2 9.25-9.42 9.34 0.12 1.28

m1 (TW) 2 7.18-7.61 7.40 0.304 4.10

m2 (APL) 3 9.84-10.42 10.10 0.293 2.90

m2 (TW) 3 7.62-8.40 8.01 0.390 4.86

m3 (APL) 2 13.95-15.36 14.66 0.997 6.80

m3 (TW) 2 8.18-8.43 8.31 0.177 1.88

Table 2-3. Summary table of dental measurements (in mm) of P. coatesi sp. nov from the Cucaracha Formation and P. wardi from the Barstovian Trinity River L. F. Abbreviations: APL, anterior-posterior length; TW, transverse width; TWhyd, hypoconulid transverse width; S, Standard deviation; V, index of Variance. P. wardi Upper Molars

Tooth Position N Range Mean S V

P2 (APL) 2 13.01-13.02 13.02 0.007 0.05

P2 (TW) 2 6.53-6.61 6.57 0.057 0.86

P3 (APL) 4 11.42-13.15 12.65 0.82 6.48

P3 (TW) 4 7.31-8.60 8.01 0.61 7.61

P4 (APL) 5 9.03-9.83 9.41 0.309 3.28

P4 (TW) 5 11.64-12.45 12.00 0.301 2.51

M1 (APL) 6 11.01-11.89 11.45 0.352 3.07

M1 (TW) 6 12.86-13.95 13.41 0.438 3.26

M2 (APL) 5 11.93-12.98 12.44 0.408 3.28

M2 (TW) 5 15.05-16.12 15.68 0.453 2.89

M3 (APL) 4 12.78-13.15 12.85 0.233 1.83

M3 (TW) 4 14.81-16.82 16.03 0.942 5.87

Table 2-3. (Continued.) P. coatesi sp. nov. Upper Molars

Tooth Position N Range Mean S V

P2 (APL) 1 12.63 12.63 - -

P2 (TW) 1 6.18 6.18 - -

P3 (APL) 2 11.79-12.65 12.22 0.61 4.97

P3 (TW) 2 8.46-8.58 8.52 0.084 0.98

P4 (APL) 4 7.79-9.41 8.56 0.710 8.27

P4 (TW) 4 11.53-13.83 12.78 1.060 8.29

M1 (APL) 6 10.81-11.37 11.09 0.202 1.82

M1 (TW) 6 14.48-15.03 14.71 0.820 5.57

M2 (APL) 5 11.29-12.83 12.36 0.720 5.83

M2 (TW) 5 14.34-17.94 16.73 1.463 8.72

M3 (APL) 7 11.63-13.58 12.51 0.803 6.41

M3 (TW) 7 16.18-17.65 16.7 0.653 3.91

Table 2-3. (Continued.) P. wardi Lower Molars

Tooth Position N Range Mean S V

p2 (APL) 2 12.13-12.42 12.28 0.205 1.67

p2 (TW) 2 4.30-4.48 4.39 0.127 2.89

p3 (APL) 3 11.96-13.22 12.57 0.631 5.02

p3 (TW) 3 4.94-5.15 5.02 0.116 2.31

p4 (APL) 7 10.05-12.01 11.27 0.583 5.17

p4 (TW) 7 6.19-7.01 6.68 0.311 4.66

m1 (APL) 9 10.57-11.53 11.00 0.354 3.22

m1 (TW) 9 8.08-10.32 9.34 0.476 5.09

m2 (APL) 9 10.88-12.5 11.95 0.524 4.38

m2 (TW) 9 10.16-11.00 10.58 0.344 3.25

m3 (APL) 8 10.43-18.56 17.67 0.789 4.46

m3 (TW) 8 10.67-11.22 10.89 0.196 1.80

m3 (TWhyd) 8 5.99-7.02 6.42 0.318 4.95

Table 2-3. (Continued.) P. wardi Upper Molars

Tooth Position N Range Mean S V

P2 (APL) 2 13.01-13.02 13.02 0.007 0.05

P2 (TW) 2 6.53-6.61 6.57 0.057 0.86

P3 (APL) 4 11.42-13.15 12.65 0.82 6.48

P3 (TW) 4 7.31-8.60 8.01 0.61 7.61

P4 (APL) 5 9.03-9.83 9.41 0.309 3.28

P4 (TW) 5 11.64-12.45 12.00 0.301 2.51

M1 (APL) 6 11.01-11.89 11.45 0.352 3.07

M1 (TW) 6 12.86-13.95 13.41 0.438 3.26

M2 (APL) 5 11.93-12.98 12.44 0.408 3.28

M2 (TW) 5 15.05-16.12 15.68 0.453 2.89

M3 (APL) 4 12.78-13.15 12.85 0.233 1.83

M3 (TW) 4 14.81-16.82 16.03 0.942 5.87

CHAPTER 3 EARLY MIOCENE FLORIDATRAGULINE CAMELS FROM PANAMA

Although not present today in North America, camelids were important faunal elements in both high and low latitude ungulate fossil assemblages during the

Cenozoic. After appearing in the fossil record during the late Eocene, camelids remained endemic to North America for almost 35 myr, only reaching the Old World during the late Miocene and South America during the Pleistocene. Camelids became extinct in North America at the end of the late Pleistocene (Pickford et al., 1994; Honey et al., 1998).

The paleogeographic and stratigraphic distribution of fossil camelids in fossiliferous sequences in North America suggest at least three main diversification stages during the Paleogene (Honey et al., 1998). Poebrotherium and Paratylopus were initial products of a radiation of basal camelids (e.g. Poebrodon) that occurred during the late Eocene and earliest Oligocene. These camelids have distinctive straight ectolophs on the upper molars, non co-ossified metapodials, brachydont dentitions, and a reduced lingual hypoconid lobe on m3. A second camelid radiation in the early

Oligocene led to the appearance of the extremely hypsodont stenomyline camelids during the early Arikareean North American Land Mammal Age (NALMA). Prior to becoming extinct during the late early Miocene (early Barstovian NALMA), these gazelle-like camelids were widely distributed throughout North America while the more brachydont poebrotheres remained poorly represented (Honey et al., 1998). A third (late

Oligocene) diversification phase led to the appearance of the “higher camelids” sensu

Honey et al., (1998) or camelids with distinct metastylids on lower molars - e.g.

Gentilicamelus and Oxydactylus. In Oregon, the appearance of “higher” camelids is

recorded in sediments from the John Day Formation with the late Oligocene occurrence of Gentilicamelus sternbergi in volcanic and volcaniclastic sequences along the western volcanic areas (active margin) of North America (Prothero, 1996; Honey et al., 1998;

Tedford et al., 2004; Albright et al., 2008). The first appearance of these camelids in the

Central Great Plains is recorded by the occurrence of “Oxydactylus” sp. in presumably

Arikareean assemblages from the Lower Harrison beds, and the occurrence of

Oxydactylus longipes in early Hemingfordian assemblages from the Upper Harrison beds (Cook, 1934; Peterson, 1904; Loomis, 1911; Honey and Taylor, 1974, Stevens,

1977). In subtropical areas of the Gulf Coast, camelids with metastylids on lower molars are represented by nothokematines that inhabited peninsular areas of Florida as early as the early Arikareean (Frailey, 1978; 1979). In subtropical areas of southwestern

North America, different groups of camelids with metastylids on lower molars are also recorded in late Arikareean tropical and subtropical volcanic sequences spanning Texas

(Stevens et al., 1977), California (Woodburne et al., 1974, Whistler and Lander, 2003), and Panama (Rincón et al., 2012).

In general, these early Neogene camelids are not only characterized by the presence of metastylids on the lower molars (Honey et al., 1998). They also have distinct entostylids on upper molars, and considerable parallelism in both postcranial

(e.g. partial co-ossification of the metapodials, elongation of the cervical vertebrae) and cranial features (closure of the orbit, lengthening of the face, reduction of the upper incisors) (McKenna, 1966; Honey et al., 1998; Janis et al., 2002). These morphologies actually represent a grade in camelid evolution that is shared among different lineages

(McKenna, 1966). As a consequence of this degree of paralelism, the taxonomic

affinities of early Neogene camelids (floridatragulines, nothokematines and oxydactylines) have remained unclear for decades with the genus Oxydactylus

Peterson, 1904, used as a taxonomic waste basket for many early Miocene camelids that exhibit any combination of these morphologies (Honey et al., 1998).

This late Paleogene radiation continued into the Neogene and by the late

Hemingfordian NALMA camelid generic diversity reached its maximum with 17 recognized genera throughout North America (Honey et al., 1998; Janis, 1998). A rapid restructuring of ungulate communities during the early Hemingfordian led to this increase in generic diversity and is likely associated with the spread of C3-grassland biomes that started during the late Oligocene (Strömberg, 2002; 2006). The steady decrease in the generic diversity of browsers observed in the fossil record from the

Great Plains during the beginning of the Neogene has been linked to decreasing primary productivity and CO2 levels (Janis et al., 2000) but more importantly, it seems associated with overall drier and cooler conditions inferred from fossil macrofloras from temperate areas of western North America (Graham, 1999).

Additional evidence of global scale changes during the Oligocene-Miocene transition was identified in the eastern equatorial marine record in the Pacific Ocean.

This interval is represented by a turnover in the faunal composition of benthonic populations of foraminifera, also known as the Marine Isotopic Event (Mi-1), which occurred ca. 23 Ma (Lear et al., 2004). Consequently, environmental changes in the continental realm are linked to global scale phenomena (increase in continental ice volume, high pCO2, general cooling, and intense volcanism) (Zachos et al., 2001;

Zachos et al., 2008) and not to merely regional (continental) tectonic processes.

Furthermore, the variation in the carbon isotope values (d13C) of n-alkanes recorded in detrital organic matter from marine sequences of the Gulf Coast (DSDP site 94) suggests that during the earliest Miocene (late Arikareean and early Hemingfordian) changes in the isotopic composition of plant detritus deposited in the Gulf Coast were insignificant (Tipple and Pagani, 2010).

While not completely agreed upon by scholars, extinction of the gazelle-like stenomyline camels during the Barstovian NALMA has been suggested to result from competition with the more diverse camelines (Honey et al., 1998). Finally, the first appearances of the extant tribes Camelini and Lamini in North America are recorded in the middle Miocene (Clarendonian NALMA), and this is known as the fourth radiation of the North American camelids (Honey et al., 1998; Webb and Meachen, 2004).

Descendants of late Miocene camelines inhabited high latitude boreal-type forests in

North America during the Pleistocene (Rybczynski et al., 2013), while lamines dispersed into South America during the Pleistocene as part of the Great American Biotic

Interchange (Honey et al., 1998; Woodburne, 2004; 2010).

The early Miocene floridatraguline fossil record. Since the original description of the early Miocene Panamanian fossils, the mammalian fauna now includes five terrestrial orders. Seventeen mammalian genera representing 14 families are known from the Centenario Fauna while 18 genera representing 13 families are known from the late Arikareean Lirio Norte L. F. (MacFadden et al., 2014; Bloch et al., 2016).

Among the ungulate fossils, floridatraguline camelids are well represented in the late

Arikareean (~21 Ma) Lirio Norte L. F. by many fossils classified in two species of

Aguascalientia (Rincón et al., 2012), but are only represented in the Hemingfordian

Centenario Fauna by a few isolated partial dentitions previously referred to cf.

Floridatragulus nanus by MacFadden et al. (2014). In a lithostratigraphic context, the late Arikareean (~21 Ma) Lirio Norte Local Fauna (L. F.) represents terrestrial mammalian communities from the uppermost part of the Las Cascadas Formation

(Figure 1-2). This interval is characterized by discrete fossiliferous sequences associated with subaerial volcanic products deposited in sporadic fluvial environments

(Rincón et al., 2012a, 2012b, 2013, Bloch et al., 2016). In contrast, the early

Hemingfordian (~19 Ma) Centenario Fauna (MacFadden et al., 2010; MacFadden et al.,

2014) is comprised of fossils recovered from volcaniclastic sequences from the upper part of the Culebra and Cucaracha Formations (Figure 1-2). These taxa inhabited a variety of sedimentary environments ranging from deltaic sequences of the upper part of the Culebra Formation to transitional and paralic sequences from the upper part of the

Cucaracha Formation (Kirby and MacFadden, 2005; MacFadden et al., 2014; Rincón et al., 2015). Although no fossil vertebrates have been recovered, the volcanic and volcaniclastic Pedro Miguel Formation followed the accumulation of the continental paleosols of the upper part of the Cucaracha Formation and represents the youngest lithostratigraphic unit in the Gaillard Cut area (Montes et al., 2012; Kirby et al., 2008;

MacFadden et al., 2014; Rincón et al., 2015).

The more tropical distribution of late Arikareean floridatragulines suggests that these early Miocene tropical camelids are descendants of an Oligocene taxon that became isolated from northern areas of the Gulf Coast as intense tectonic (and volcanic) activity favored the colonization of tropical volcanic terrains of the Chorotega

Block (Panama) during the late Arikareean (Rincón et al., 2012; Bloch et al., 2016).

Herein, I describe recently recovered partial camelid fossils collected from early

Miocene (~21 to 19 Ma) volcanic and volcaniclastic sequences from the Panama Canal area. The new floridatraguline fossils include a partial skull herein referred to

Aguascalientia panamaensis and a partial skull and associated mandibles of a new genus of floridatraguline camelid from the Lirio Norte Local Fauna (~21 Ma). Also, recently recovered partial floridatraguline dentitions and a metatarsus from the

Centenario Fauna (~19 Ma) are here referred to a new species of Floridatragulus. In addition to justifying the systematic placement of the new taxa, I discuss the taxonomic cogency of Floridatragalus nanus Patton, 1969 by looking at the natural variation in dental dimensions and crown morphology observed in early Miocene camelid populations from the Gulf Coast (~Lat 28° N) and Panama (Lat ~9° N).

I also explore the relationship between tectonic processes and diversification of ungulates in this distinctive (tropical) tectonic province by looking at the phylogenetic relationships between the early Miocene camelids from tropical and subtropical assembles in southern North America. Finally, I discuss different paleobiogeographic scenarios that may account for the differences in the artiodactyl faunal composition and the anomalous biostratigraphic patterns observed in these early Miocene mammalian assemblages from Panama.

Early Miocene higher camelid paleobiogeography in southern North

America. Floridatraguline camels had a tropical and subtropical North American distribution (Figure 3-1) during the Miocene with no occurrence of this group in well- sampled fossiliferous assemblages from higher latitudes (Honey et al., 1998; Rincón et al., 2012). The elongated snouts and brachydont dentitions of floridatragulines suggest

that they represent selective browsers (Janis, 2008), with a posteriorly open orbit, laterally placed caniniform upper incisors, nearly square upper molars with distinct entostyles, lower molars with faint to strong ectostylids, and a divided posterior heel on the m3 (Maglio, 1966; Honey et al., 1998, Rincón et al., 2012). The combination of morphologies in the skull of Floridatragulus dolichanthereus (the only floridatraguline previously known from a partial skull) initially suggested hypertragulid relationships

(White, 1940; 1947), but Maglio (1966) confirmed the presence of distinctive camelid morphologies (e.g. camelid hook on the ascending ramus) in this taxon. In particular, the presence of a complete post-orbital bar in an undescribed skull (AMNH 31864) of

Floridatragulus dolichanthereus from the Thomas Farm locality (Prothero, 1996) may provide a new interpretation about the origins of this group of camels. More importantly, the relationships of these tropical camelids within Camelidae can be reevaluated.

Based on late Arikareean partial dentitions of the floridatraguline Aguascalientia discovered in areas of the expansion of the Panama Canal, Rincón et al., (2012) suggested that late Arikareean Aguascalientia is the sister taxon of the Hemingfordian-

Barstovian Floridatragulus and both genera diversified in tropical areas of southern

Central America after colonizing volcanic terrains of the Central American arc during the earliest Miocene. The oldest species of Floridatragulus, F. nanus Patton, 1969, is only known from a single m3 from the early Hemingfordian Garvin Gully L. F. in Texas

(Figure 3-1). Two species of Floridatragulus (F. dolichanthereus White, 1940 (genotype) and F. barbouri White, 1947) were described from the early Hemingfordian Thomas

Farm Fauna in Florida. Although relatively smaller (~12% than F. dolichanthereus), the partial dentitions initially described as F. barbouri, were included in the hypodigm of F.

dolicanthereus by Maglio (1966), thus recognizing only one species at Thomas Farm. F. dolichanthereus and F. nanus are found in association with diagnostic early

Hemingfordian taxa that include the amphycyonine Amphycyon longiramus, the syntethoceratine Prosynthetoceras texanus, the rhino Floridaceras whitei, the equid

Anchitherium clarencei, and the sciurid Petauristodon in Thomas Farm, but also in association with the entelodont Dinohyus hollandi in the Garvin Gully L. F. in Texas

(Patton, 1969). Although relatively larger than Floridatragulus dolichanthereus, the late

Hemingfordian?-early Barstovian Floridatragulus texanus from the Burkeville L. F. in

Texas (Figure 3-1) has a shallower invagination on the posterior border of the talonid of m3 and relatively less reduced premolars (Patton, 1969). The Barstovian

Floridatragulus hesperus Patton, 1969 from the Gulf Coast (Cold Spring Fauna) is characterized by having a distinctively strong and posteriorly recurved metastylid on m3 and it is the largest member of the genus (Patton, 1969).

Nothokemas White, 1940, the only other camelid described from Thomas Farm, differs from Floridatragulus in the lack of the P1/p1, having a m3 talonid with no posterior projection of the entoconid (not forming a double enamel loop), a relatively more hypsodont dentition, stronger stylids on the lower molars, and a ventrally inflected symphysis (Frailey, 1978; Honey et al., 1998). Nothokemas is also known from early

Arikareean (SB-1A Local Fauna) deposits in Central Florida (N. waldropi Frailey, 1978;

Tedford et al., 2004) and early Hemingfordian (N. floridanus from the Garvin Gully L. F.) assemblages from the Gulf Coast of Texas (Patton, 1967; Patton, 1969) (Figure 3-1).

Although the relationships between Nothokemas and other early Miocene camelids (e.g.

Priscocamelus Stevens et al., 1969, Australocamelus Patton, 1969, and the miolabines)

have remained unclear, Nothokemas was tentatively grouped with the small camelid

Gentilicamelus Loomis, 1936 from Oregon in a subfamily with uncertain relationships, the “Nothokematinae” (Honey et al., 1998). The informal “Nothokematinae” might also include other camelids from the Gulf Coast, such as the monospecific taxon

Delahomeryx browni Stevens, 1969 from the late Arikareean Castolon L. F. in Texas

(the same assemblage where Aguascalientia sp. was initially reported by Stevens et al.,

[1969]). Delahomeryx browni was originally placed into the Nothokemadidae of White,

1947 based on having a nothokemas-type hypoconulid (formed by two grinding surfaces with an entoconid slightly overlapping posteriorly the hypoconulid forming a distinctive cleft) but exhibits distinct ectostylids on lower molars. Unfortunately, the type specimen (TMM 40620-7) does not preserve the anterior part of the mandible and the presence of a p1 cannot be confirmed. The monospecific genus Priscocamelus Stevens et al., 1969 represents a more hypsodont species with relatively narrower cheek teeth.

Based on interpreted shared derived morphologies, Priscocamelus has been linked to the basal cameline alticamelines as initially proposed by Stevens (1969) and Stevens et al., (1977).

Systematic Paleontology

Class MAMMALIA Linnaeus, 1758

Order ARTIODACTYLA Owen, 1848

Suborder TYLOPODA Illiger, 1811

Family CAMELIDAE Gray, 1821

Subfamily FLORIDATRAGULINAE Maglio, 1966

Type species: Floridatragulus dolichanthereus White, 1940.

Included genera: Aguascalientia, Floridatragulus, Floridatragulinae gen. et. sp. nov.

Emended diagnosis. Differs from “Nothokemathinae”, Stenomylinae, Miolabinae, and Protolabinae in having nearly square upper molars with prominent styles, upper teeth anterior to P2 spaced by distemata, more reduced lower premolars, p4 with oval

(rather than wedge-shaped) occlusal outline, ectostylids/entostyles present on molars, m3 hypoconulid with lingual and labial selenes, laterally placed anterior upper incisors separarated by diastemata, p1-p2 diastema. Futher differs from Stenomylinae in having brachydont molars with distinct metastylids and mesostyles. Further differs from

Camelinae in having brachydont dentition and lacking a pocketed maxillary fossa.

Further differs from Nothokematinae in having stronger ribs on upper molars, retention of the p1, a strongly co-ossified symphysis, more reduced premolars, and a relatively deeper mandible anterior to the p2 with no ventral inflection. Further differs from

Protolabinae in lacking laterally expanded anterior nares, an elongate M3/m3, and the faint metastylids on lower molars. Further differs from Miolabinae in retaining a p1 and having a relatively shallow maxillary fossa.

GENUS AGUASCALIENTIA Stevens et al., 1977

Aguascalientia panamaensis Rincón et al., 2012

Figure 3-2; Tables 3-1, 3-2; Appendix D

Holotype. UF 236939, with left c1; right dentary with c1-p3, m1-m3, and mandibular symphysis (Rincón et al., 2012).

Paratypes. UF 254129, right and left dentaries with right i1-i2; left i1-p4; and mandibular symphysis; UF 254124, right and left dentaries with right p3, m1, left p2, p4, m2-m3; right p3, m1 (broken); and mandibular symphysis.

Referred material. UF 281478, partial skull with both nasals, right and left maxillae, alveoli for the C1 and P1, RC1-P4 (RC and RI1 associated), and left C1

(partial) and P2; UF 244156, right DP3; UF 280772, right DP3; UF 259878, right DP3;

UF 280447, left DP3; UF 275283, right DP3; UF 267049, left DP4; UF 275267, left DP3;

UF 280745, left P1; UF 280722, left P3; UF 280213, left P2; UF 280119, left P2; UF

275277, left P3; UF 280574, left P1; UF 244199, left P3; UF 267047, left P2; UF

275388, left P1; UF 281051, left M1; UF 281478, right P1-M2, left P2; UF 275169, left

P1-M3, right C, right P2-P3, right M3; UF 280897, left P2, P4-M1; UF 281471, left P2;

UF 281472, left M2; UF 281473, right P3; UF 275457, right P2; UF 267137, left C1; UF

275445, left C1; UF 280025, left P4; UF 281478, right C1-P4, left C1 (partial), and left

P2; UF 271620, left M3; UF 246825, right M3; UF 280865, right P3-M1, M3, left P3, UF

280862, right M1-M2, left P2, left P4-M2; UF 275169, partial skull with right C1, P2-P3,

M3, left P1-M3; UF right maxilla with P3-M3; UF 281038, left m2; UF 254121, left m2;

UF 280817, left m2; UF 246836; left m2-m3; UF257198, left m3; UF 280821, right m2- m3; UF 246828, right c1-p2, p4-m1; UF 280803, left m1; UF 254122, left m1; UF

280125, left m1; UF 281056, left m1; UF 280181, left m1; UF 280049, left m1; UF

246801, right c1-m1; UF 280832, right p2; UF 275276, right p4; UF 246803, left p3; UF

244316, left p2; UF 275273, left p1; UF 280877, right p4; UF 275182, right m3, UF

254123, left m3; UF 267142, right p3; UF 275289, right c1; UF 254118, left p4; UF

254120, left p4; UF 281036, right p4; UF 280575, left p1; UF 275419, left p1; UF

275174, right p4; UF 280980, left p4; UF 281039, left p1; UF 275175, left dp4; 280161, right dp4; UF 246813, right dp4 (partial); UF 246802, right p1-m2, left p1 and partial symphysis; UF 244184, right dp4; UF 280011, left m3 (partial); UF 254114, left m3

(partial); UF 280831, left c1; UF 280628, left p1; UF 281059, right p1, right p4-m3, Lc1;

UF 281470; right p1; UF 280834, left p3; UF 281476, left m3; UF 281059, paired mandibles with right p1, p4-m3, left c1 and symphysis.

Locality and horizon. Lirio Norte (site key YPA024 in UF Vertebrate Paleontology

Collection), Panama Canal area, Panama, Central America. Fossils were collected in the upper part of the Las Cascadas Formation (Lirio Norte L. F.) (Rincón et al., 2015).

Recently obtained U/Pb ages from an underlying volcanic horizon (andesitic tuff) placed these fossils in the earliest Miocene (~21 Ma) (Bloch et al., 2016), equivalent to the late

Arikareean NALMA, Ar4 (Figure 1-2).

Description

Skull. A partial skull (UF 281478) preserves fragments of both nasals and the right and left maxillae with the alveoli for the C1 and P1, RC1-P4 (RC and RI1 associated), left C1 (partial) and P2 (Figure 3-2). The posterior part of the nasals is pristine while the anterior ends are missing. The medial suture is distinct as are the lateral sutures with the maxillae. Although not completely preserved, this suture runs anteriorly for more than 55.0 mm, while the anterior ends project laterally from the medial suture ~30 mm at the widest point (Figure 3-2A-C).

The sutures between the maxillae and palatines run anteriomedially from the lingual side of the M1 ending at the anterior root of the P3 on the medial plane. Two faint posterior pits are the only evidence of palatine foramina on the posterior part of the maxillae (Figure 3-2). The rostral (anterior) parts of the maxillae are only partially preserved with no clear evidence of the sutures with the premaxillae. The C1-P1 diastema is ~23.0 mm long while the lateral end of the maxilla is located ~18 mm anterior to the alveoli (Figure 3-2C-D). The diastema between the P1 and P2s is 23.0

mm. The width of the maxilla between the C1 is 14.2 mm, and between the P1s and P2 is 6.0 and 18.3 mm, respectively. The infraorbital foramen, only visible on the right side of the partial skull, is located 7.0 mm above the anterior root of the P4 (Figure 3-2C).

Upper anterior dentition. UF 281478 (Figure 3-2) includes right C1-P4, left C1 and left P2. The C1 is approximately 20% larger (APL) than the P1 (Figure 3-2E-G;

Table 3-2). The C1 is posteriorly curved and single rooted. The crown of C1 has a distinctive acute apical tip with a bulge at the base just above the enamel-dentine junction (Figure 3-2B). The P1 is more elongate (APL>TW), double rooted (with strongly apprised roots as evidenced by a distinct furrow in lateral view), and more laterally compressed than the C1 (Figure 3-2H-J). A small but distinct ridge extends towards the apical anterolabial tip from the basal anterolingual part of the crown of P1 (Figure 3-2I).

The P2 (Figure 3-2D) is elongate (APL>TW) and double-rooted. The protocone is the most distinct cusp while the parastyle and metastyle are located lower in a posterolingual narrow talon. Compared to the P3, the labial cingulum on the P2 is weaker, only extending from the lingual side of the parastyle and connecting with the metastyle by a narrow and faint cingular segment. The P3 is triple-rooted and the crown is similar in length to that of the P2 but more transversely expanded (Figure 3-2D). The

APL length is 10.14 mm long while the TW is 5.34 mm (Appendix D). The lingual root is located distal to the midline of the crown and is closer to the posterior than the anterior root. Similar to other early Miocene camelids, the crown of P4 is molariform, wider than that of P3 (P4APL: 8.15 mm; TW: 8.6 mm), and has a distinctive anterior and posterior labial cingula restricted to the labial segments of the crown (Figure 3-2D).

Discussion and Comparisons

Despite being only partially preserved, the nasals exhibit the extreme elongation observed in the lower mandibles of the small floridatraguline camel Aguascalientia from the same assemblage (Rincón et al., 2012b). Together, the nasals are approximately

15% wider and relatively more elongate (despite breakage) than those of

Poebrotherium sp. (UF 216914) from Nebraska (Table 3-1) and although not as extreme as in the Hemingfordian F. dolichanthereus, the maxillae of A. panamaensis are more anteroposteriotly elongate than those of Poebrotherium sp. from Nebraska.

Direct comparison between the upper anterior dentition (P3-P4) preserved in UF

281478 and other specimens (e.g. UF 254125) previously referred to A. panamaensis support my taxonomic placement (see Rincón et al., 2012:fig.4). The crown dimensions of P3 in UF 281478 are similar to those reported for UF 254125 (Rincón et al,

2012:fig.4; Figure 4A–C; Appendix D). The crown is also elongate, trenchant, lacks external ribs, and has a strong metacone with an interrupted internal cingulum. The anterior crescent is weak, developed lingually over the anterior root, and bearing small cuspules. The posterolingual crescent is weak but distinct and extends lingually from the base of the metacone toward the posterior margin, reaching the lingual part of the base of the metastyle. Although slightly smaller than that of UF 254125 (Appendix D), the P4 of UF 281478 is also sub-molariform with a well-developed parastyle and metastyle. The metastyle is more prominent and recurved than the parastyle. In addition to the distinctive extreme elongation on the partial preserved nasals and maxillae, the floridatraguline Aguascalientia further differs from Floridatragulinae gen. et. sp. nov. from the same fossil assemblage (see below) in being ~18% smaller (APL P2-M3 : ~ 60 mm vs. 75 mm for Floridatragulinae gen. et. sp. nov) and having a stronger anterior

cusp on P2. Aguascalientia panamaensis is ~ 30% smaller than F. dolichanthereus

(APL P2-M3: ~ 80 mm) from Thomas Farm (Maglio, 1966).

Genus Floridatragulus White, 1940 = Hypermekops White, 1942.

Type species. Floridatragulus dolichanthereus (White, 1940) ( = Hypermekops

White, 1942; = F. barbouri White, 1947).

Included species. Floridatragulus texanus Patton, 1969; Floridatragulus hesperus

Patton, 1969; Floridatragulus nanus Patton, 1969; and Floridatragulus sp. nov. from

Panama.

Revised diagnosis. Floridatraguline camelid that differes from Aguascalientia in having a p2-p3 diastema that is longer that the p4APL, lower c1 separated form the p1 by diastema of m1-m2 length or greater, more elongate rostrum. Differs from

Floridatragulinae gen. et sp. nov. in lacking a p1-p2 diastema and distinct protostylids on lower molars. Further differs from Nothokemas in having a completely fused symphysis, lacking a ventral inflection of the mandible below the p2, p1 present, lower premolar lacking distinct anterolingual stylids, and m3 hypoconulid with posterior projection of the entoconid.

Distribution. Floridatragulus dolichanthereus is known from the early Miocene

(early Hemingfordian) Thomas Farm L. F. from Florida (White, 1940). F. texanus from the early Barstovian Point Blank Fauna and Trinity River L. F. in Texas (Patton, 1969;

Honey et al., 1998); F. hesperus from early Miocene (late Barstovian) Cold Spring L. F. in Texas (Patton, 1969); F. nanus from the early Miocene (early Hemingfordian) Garvin

Gully L. F. in Texas (Patton, 1969); and Floridatragulus sp. nov. from the early

Hemingfordian Centenario Fauna (MacFadden et al., 2014) from the Panama Canal area (Figure 3-1).

Floridatragulus sp. nov.

( = cf. F. nanus MacFadden et al., 2014)

Figure 3-3, 3-4; Table 3-2.

Holotype. UF 246854, partial right and left mandibles with Rp4-m2, Rm3, Lp4-m1 and partial symphysis from Hodges Microsite (YPA026), late Centenario Fauna

(MacFadden et al., 2014).

Referred specimens. 1) Hodges Microsite (YPA026), late Centenario Fauna

(MacFadden et al., 2014): UF 246853, right DP3-M1; UF 271665, right DP4 ; STRI

38904, right P3; UF 280240, left M1; UF 275485, right M3 ; UF 280023, left M2; UF

281093, left M1; UF 267102, right M3; UF 245482, left M3; UF 275486, left M3; UF

280991, left M3; UF 280144, left lower incisor; UF 281137, partial symphysis; UF

275446, right p3; UF 280653, left p2; UF 280091, left p3; UF 271595, partial right mandible with Rp4, Rm2-m3; UF 280808, right m1; UF 275473, left m1; UF 280737, right m3; UF 275307, partial distal right radius; UF 271170, right ulna; UF 257204, left metatarsal III-IV (YPA026); 2) Centenario Bridge, late Centenario Fauna (YPA037), late

Centenario Fauna (MacFadden et al., 2014): UF 257201, partial left mandible with Lp3

(partial)-p4 and symphysis; 3) Hodges Hill North, late Centenario Fauna: UF 245482; left M3.

Age and distribution. Early Miocene (~19 Ma), equivalent to the late Arikareean- early Hemingfordian Centenario Fauna (Figure 1-2) in the Panama Canal basin

(MacFadden et al., 2014).

Diagnosis. Smallest known species of Floridatragulus. Differs from other species of Floridatragulus in having a double rooted p1 with strongly appresed roots, p2 with fossettid posterior to the protoconid, and p3 with reduced paraconid.

Description

Upper dentition. The crown of P3 (Figure 3-3D-F) is elongate (APL: 8.57 mm;

TW: 4.83 mm) and has three roots with the lingual root located close to the posterolabial root (Figure 3-2, 3-3; Table 3-2). The crown lacks external ribs, and has a heavily worn but distinct paracone interrupting an internal cingulum that widens posteriorly. The parastyle, paracone, and metastyle are aligned, forming a straight labial margin. The anterolingual crescent is low and formed by a not very distinct cingular segment. The posterolingual crescent is also low and formed by a small cingular segment that extends lingually from the base of the paracone towards the posterior margin, but which never reaches the lingual part of the base of the metastyle.

The upper molars of Floridatragulus sp. nov are square (Table 3-2), brachydont, and have distinct entostyles (Figure 3-3A-C; G-I). In occlusal view, the mesial crest overlaps buccally the distal half of the crown, resulting in a very prominent mesostyle and a deep recess anterior to the juncture of the paracone and metacone (Figure 3-

3A,G). Strong ribs extend up each crest from the base of the crowns to the tip of both the paracone and metacone. The entostyles are located lingually between the anterior and posterior crescents and originate at the base of the crown (Figure 3-3A-C). In upper molars with little-to-no wear, two twinned segments make up the entostyles, with a larger posterior segment extending higher apically. The anterior and posterior cingula are weak and restricted to the lingual margins of the crescents. The para- and metastyle

are well developed in M1 (UF 246853) but reduced in the M3. The M3 (UF 257202) has a distinctive posterior segment that is transversely reduced.

Deciduous upper dentition. UF 246853 represents a right partial maxilla of a young individual that preserved the crowns of DP3-M1 (Figure 3-3G-I). The crown of

DP3 is elongate (APL: 9.75 mm; TW: 6.53 mm) and has well-developed paracone

(primary cusp), metacone, and hypocone (posterior crescent). Strong, distinct ribs are located labially on both the paracone and metacone. The mesostyle is the most distinct labial style. The DP3 of Floridatragulus sp. nov. from Panama exhibits a distinct narrow cingular segment that is located lingually above the anterior root (Figure 3-3G-H).

The length of DP4 of Floridatragulus sp. nov. (UF 246853) is square (8.17 mm and the TW: 8.18). The crown is molariform and differs from the M1 in having a parastyle that is distinctively stronger than the mesostyle (Figure 3-3G-I). Similar to the M1, the posterior crest overlaps anterolabially with the anterior crest, resulting in a very prominent mesostyle. A strong rib extends up each crest from the base of the crown to the tip of both paracone and metacone. Confluent entostyles occur lingually between the anterior and posterior crescents (Figure 3-3G-I).

Mandible. The holotype (UF 246854) is a partially preserved mandible that includes alveoli for right and left single-rooted p1s, right and left double-rooted p2s and

Lp3, and the crowns of Lp4-m2 and associated Rp4-m2, m3 (Figures 3-4, 3-5, 3-6).

Although the symphysis is not completely preserved in the specimen, the APL of the p1- p2 diastema is similar to the m1 APL; whereas the p2-p3 diastema represents about

66% of the combined p4-m1 APL. A second partial left mandible (UF 257201) includes a completely co-ossified symphysis, the crown of p3 (broken) and a complete p4. The

symphysis is strongly fused, relatively narrow, and shallow (Figure 3-6). The single- rooted c1 is separated from the incisors by a diastema of unknown length and from the p1 by a diastema that is approximately equal to the combined length of the p4-m1. The p1 is separated from the p2 and the c1 by diastemata that are similar in length to the length of the p4-m1 series. In occlusal view, the posterior edge of the symphysis is located below the midpoint of p1-p2 diastema (Figure 3-6). The mental foramen is located below the posterior end of the alveolus for the c1. A p2-p3 diastema similar in length to the p4-M1 APL is present in the holotype (Figure 3-4) and also in UF 257201

(Figure 3-6) with comparable dimensions.

Lower dentition. Based on the alveoli preserved in UF 257201 and UF 281137, the c1 is oval (APL>TW) and approximately 25% longer than the first premolar (Table 3-

2). Although no complete crown of the p1 is available for description, the partial roots preserved in UF 281137 and UF 257201 suggest that the p1 is transversely compressed with strongly appressed roots (Figure 3-6C). The crown of p2 is simple. It has a distinct metaconid (principal cusp) with anterior and posterior cristids connecting it to the entostylid and the paraconid (Figure 3-5A-C). The dimension of the p2 are APL:

7.56 mm and TW: 3.31 mm. The p2 and p3 lack distinct lingual stylids; however, there is a single cuspid in the talonid and also a distinctive posterior fossetid or pit posterior to the main cuspid. The crown of p3 (Figure 3-5D-F) is similar in size and morphology to the p2, differing only in the development of the talonid. The entoconid and entostylid enclose a small fossetid that is posterior to the main cusp but located on a sharp cristid that connect the metaconid with the talonid (Figure 3-5D). ). The entoconid is reduced and the crown lacks a distinct lingually open valley. The p4 represents almost 60% of

the m1APL in UF 246854 (Figure 3-4A-B). The crown of p4 is oval with a talonid that is relatively less expanded transversely that anterior segment of the crown. The p4 metaconid is tall and distinct, the entoconid narrow, and the distal edge of the hypoconid slightly overlaps the metaconid lingually. In lateral view, the anterior cusp is low and more reduced anteroposteriorally that that of the p3 (Figure 3-5B). The entoconid and the hypoconid are connected to the metaconid by two distinctive cristids.

A posteriorly opened lake (visible even in advanced wear stages) is confined to the posterior part of the talonid (Figure 3-5).

The lower molars are brachydont with distinct anterior and posterior fossetids

(Figure 3-4F-H, 3-7A-C). The lower molars have discontinuous and overlapping internal crests where the metaconid crest remains isolated until middle to late wear stages. The presence of ectostylids in the lower molars is variable. They are restricted to the basal part of the protoconid and hypoconid on the m1-m3 of UF 246854 and 245541, but are taller between the hypoconid and hypoconulid on the m3 in UF 271595 (Figure 3-7A-C).

Parastylids are faint on m1 and m2, and barely discernible on the m3. The invagination on the talonid of m3 is restricted to the apical portion of the crown and the posterior closure of the fossetid located on the heel of the hypoconulid occurs during early wear stages. The hypoconulid is reduced transversely, in some cases representing about

60% of the maximun traversal width of the molar (Table 3-2). The posterolingual surface of the m3 exhibits an enamel wrinkle (the occlusal expression resembles a small cuspulid) running from the basal (lingual) part of the entoconid crest and reaching the occlusal surface at the posterior end of the hypoconulid (Figure 3-4, 3-7). There is no

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evidence of a posterior cingular segment (Figure 3-7D-F) in any of the camelid specimens from Panama.

Metatarsus. UF 257204 is a complete left metatarsus with metatarsals III and IV

(Figure 3-8) recovered from the same conglomeratic sandstones of the Hodges

Microsite (late Centenario Fauna, MacFadden et al., 2014). It represents an adult individual with completely fused distal epiphyses. The proximal co-ossification between metatarsals (Figure 3-8A,C) is significant and extends distally for approximately 40% of the total length of the metatarsus from the proximal end of the posterior end of the plantar process (Figure 3-8B).

Small but distinct articular facets in the external sides of both metatarsal III and IV suggest that extremely reduced splints of metatarsals II and V were present. In posterior and anterior views, the metatarsal seems slightly asymmetric, with metatarsal III being more robust than metatarsal-IV (Figure 3-8). In plantar view (Figure 3-8E), metatarsal III has a large anterior articular facet for the ecto-entocuneiform and a smaller facet for the articulation with the entocuneiform. There is no evidence of the presence of any articulation facet in the postero-tibial face of the metatarsal III. In cross section, both the distal and proximal portions are “D” shaped. In the distal surface of the metatarsals, the carinae are confined to the plantar face (Figures 3-8C, E).

Comparisons. The DP3 of Floridatragulus sp. nov. is 12% smaller than the DP3 of Aguascalientia panamaensis (Table 3-2; Rincón et al., 2012) and differs from it in having a relatively more abbreviated anterior segment. The P3 is ~20% smaller than that of A. panamaensis yet exhibits a low anterolingual crescent formed by a not very distinct cingular segment present in other floridatragulines. The DP4 is ~12% smaller

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than that of Aguascalientia panamaensis from the Lirio Norte L. F. (Rincón et al., 2012;

Rincón et al., 2015; Table 3-2). The upper molars of Floridatragulus sp. nov. are 10-

15% smaller than those of A. panamaensis with absolute dimensions that are comparable to the upper molars of A. minuta from the Lirio Norte area (Rincón et al.,

2012). The p1 of Floridatragulus sp. nov. is transversely compressed and has strongly appressed roots, a morphology not present in any other early Miocene floridatraguline.

The dimensions of the p2 of Floridatragulus sp. nov. are similar to those reported for the p2 of A. minuta (Table 3-2; Rincón et al., 2012), and similar to Oxydactylus longipes from the Runningwater Formation in Nebraska (Frick and Taylor, 1978), Floridatragulus sp. nov. lacks the distinct lingual stylid on p2 of Nothokemas and the weak lingual stylid of Aguascalientia panamaensis. The entoconid of p3 is relatively more reduced than that of Nothokemas, therefore lacking a distinct lingually open valley. Compared with the p4 of Poebrotherium, the crown is less wedge-shaped (similar to that of

Aguascalientia) with a talonid that is relatively less expanded transversely. Similar to other species of Aguascalientia and Floridatragulus, the entoconid and hypoconid are connected to the metaconid by two distinctive cristids; the symphysis is strongly fused, relatively narrow and shallow (Figure 3-6) and the mental foramen is located below the posterior end of the alveolus for the c1.

The distinctive p2-p3 diastema of Floridatragulus is present in the holotype (Figure

3-4) and also in UF 257201. Similar to those of Floridatragulus dolichanthereus, the parastylids are weak on m1 and m2, and barely discernible on the m3. The invagination on the talonid of m3 is restricted to the apical portion of the crown as in the type of

Floridatragulus nanus (Patton, 1969:170) and some specimens of F. dolichanthereus

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from Thomas Farm (Figure 3-7). Contrary to Aguascalientia, the posterior closure of the fossetid located on the heel of the hypoconulid occurs during early wear stages. The hypoconulid is also relatively more reduced transversely than in Aguascalientia (and F. dolichanthereus), in some cases representing about 60% of the maximun traversal width of the molar (Table 3-2). Similar to the type of F. nanus from Texas, the posterolingual surface of the m3 exhibits an enamel wrinkle (the occlusal expression resembles a small cuspulid) running from the basal (lingual) part of the entoconid crest and reaching the occlusal surface at the posterior end of the hypoconulid (Figure 3-4, 3-

7). There is no evidence of posterior cingular segment (Figure 3-7D-F) in any of the camelid specimens from Panama. Finally, the metatarsus of Floridatragulus sp. nov. from Panama is about 50% shorter than the metatarsus of F. dolichanthereus (UF

176198) from the Thomas Farm fossil site (approx. total length = 215 mm), but relatively more robust than that of F. dolichanthereus, with a ratio of ~0.11 for the length between the minimum (medial) width of the shaft and the total length of the metatarsal. This ratio is 0.04 for the relatively larger F. dolichanthereus.

Discussion and Comparisons

Partial dentitions referred to Floridatragulus sp. nov. exhibit the following floridatraguline hallmarks: (1) unreduced p1, (2) brachydont teeth, (3) an unusually elongate mandible with two caniniform teeth (c1–p1) well-separated by diastemata, (4) a long and narrow horizontal mandibular symphysis, (5) reduced lower premolars, (6) intercolumnar pillars (entostyles and ectostylids) present in molars, and (7) a m3 hypoconulid composed by distinctive lingual and labial selenes. The presence of a diastema between the p2 and p3 places the new fossils from Panama in the genus

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Floridatragulus White, 1940. Although partially preserved, the double rooted p1 with strongly appressed roots is a morphology not observed in any other floridatraguline.

Furthermore, the less developed paraconids on p2 and p3 (more similar to those of

Aguascalientia), presence of a fossettid posterior to the protoconid of the p2 (not present in any species of Floridatragulus), and the presence of a double rooted first premolar are herein interpreted as autopomorphies for this new species.

This new species of Floridatragulus, although rare in fossiliferous localities of the

Centenario Fauna (MacFadden et al., 2014), is comparable in tooth dimensions to the

(~21 Ma) Aguascalientia panamaensis described by Rincón et al., (2012) from the Lirio

Norte L. F. in the Canal area. However, in order to explore the morphological variation among small early Miocene floridatragulines, and therefore, justify my taxonomic placement, a combined total of 569 early Miocene (Ar4-He1) camelid premolars and molars of Floridatragulus, Aguascalientia, and Nothokemas were compared and measured. For isolated teeth, tooth positions were assigned through detailed morphological comparison with holotypes and/or other confidently identified specimens.

In cases where the tooth was incased in a maxilla or mandible, dimensions were noted as estimated (Appendix D). In summary, I included in the analysis: 1) 196 measurements from partial dentitions of Aguascalientia (A. panamaensis and A. minuta) from the Lirio Norte L. F.; 148 from the genus Floridatragulus (including F. dolichanthereus, F. barbouri, F. texanus, F. hesperus, F. nanus from the Gulf Coast and cf. F. nanus from Panama); and 56 measurements from other camelids from the Gulf

Coast and Panama (Appendix D). As a comparative tool, 28 m3s referred to Paleolama

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mirifica from the early Pleistocene Leisey Shell 1A Pit (Morgan and Hulbert, 1995) housed at the FLMNH were measured to define a baseline for the statistical analyses.

I identified a small sample of isolated individual m3s (UF 203863, UF 262026 and

UF 271333) from the Hemingfordian Thomas Farm site in Florida whose crown dimensions overlap those reported for the holotype of F. nanus from Texas (Patton,

1969:170) (Figure 3-9); furthermore, I noted that some of the morphologies included in the diagnosis of F. nanus (Patton, 1969:170) are variably present in the m3s of other

Miocene camelids from the Gulf Coast and Panama. The posterior cingulid (Figure 3-7) is variably present in the sample of Floridatragulus sp. from Florida (present in two out of the fourteen specimens) but is not present in any of the m3s of Aguascalientia or

Floridatragulus sp. nov. The tubercular cuspulids between the labial and lingual grinding surfaces on the hypoconulid of F. nanus (TMM 40067-194; Figure 3-7D-F,H) are variably present in the little-worn m3s of Floridatragulus sp. nov. (present in two out of four specimens), present in two out of the nine specimens of A. panamaensis (Figure 3-

7), and present in two out of the seven specimens of Floridatragulinae gen. et sp. nov., a basal floridatraguline camel (Figure 3-7) from the Lirio Norte L. F. (see below), but it is never present in the little-worn specimens from Thomas Farm or specimens from any other Hemingfordian sites in the Gulf Coast (e.g. the Miller Site). However, a distinct wrinkle in the enamel (resembling a cuspulid in occlusal view), similar to that present in the type of F. nanus, runs on the posterolingual surface of the hypoconulid lobe of the m3 in the type of Floridatragulus sp. nov. (Figure 3-4F-H) while a more posterior wrinkle on UF 271595 resembles a cuspulid located between the two grinding surfaces of the hypoconulid in occlusal view (Figure 3-7A-B). The ectosylids between the protoconid

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and hypoconid on m3 are also variable in both frequency and morphology in the studied floridatraguline sample. They vary from being weak to absent in fossils from Panama to strongly blocking the transverse valleys between crescents in teeth with little wear of

Floridatragulus sp. from Thomas Farm. Furthermore, this variation is also observed in the relatively small sample of Floridatragulus sp. nov. from Panama. Ectostylids are weak and basally restricted to the labial opening of the transverse valleys in the type

(Figure 3-5) but are distinct and more apically placed in UF 271595 (Figure 3-7A-C).

Consequently, the morphological variation observed in the smaller m3s from

Thomas Farm does not allow them to be confidently assigned to F. nanus. Moreover, given the fact that F. nanus is only known from an isolated m3 in the type locality, an estimation of the natural variation in size and morphology is not possible. The coefficient of variation for m3 specimens referred to Floridatragulus from Thomas Farm is ~11.3

(Appendix E), tentatively suggesting the presence of a small floridatraguline given the variation observed in the Aguascalientia panamaensis sample (CV= ~ 5.0) and

Paleolama (CV= ~4.0); however, I am reluctant to refer those specimens from Thomas

Farm to F. nanus based solely on dimensions (Figure 3-9). In this respect, early

Miocene m3s from different floridatraguline populations (Panama and the Gulf Coast) at least partially parallels the distinctive morphologies (autopomorphies) proposed form F. nanus (presence of cuspulids on the occlusal surface on the m3 hypoconulid, the expression of the posterior cingulid, and the development of the ectostylids). The holotype of F. nanus (TMM 40067-194, Figure 3-7D-F) displays morphologies that are also shared to some degree with other camelid populations from Panama (e.g.

Floridatragulinae gen. et. sp. nov. from the Lirio Norte L. F., see below), although each

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one has its own variation among the studied early Miocene populations. From this interpretation, F. nanus Patton, 1969 represents a nomen dubium given the unfeasibility of precisely allocating small floridatraguline m3s (e.g. a worn specimen of

Aguascalientia or any small floridatraguline not yet discovered) within a specific camelid genus. Furthermore, some of the morphologies preserved in the holotype of F. nanus are shared with at least three early Miocene genera within Camelidae: the floridatragulines Aguascalientia and Floridatragulus, and even in the new genus of floridatraguline camel from Panama (see below). Finally, the partial metatarsus here referred Floridatragulus sp. nov. exhibits proximal co-ossification of metatarsal III and metatarsal IV, an osteological condition reported in many camelid lineages during the early Miocene (Janis et al., 2002). Interestingly, this morphology is not observed in UF

176198, the only complete camelid metatarsus referred to Floridatragulus dolichanthereus from Thomas Farm site. The distal carinae of the metatarsal are confined to the plantar face (Figures 3-8C, E) in both specimens.

Floridatragulinae, gen. nov.

Aguascalientia (in part), Rincón et al., 2012

Type and only known species. Floridatragulinae gen. et. sp. nov. from the Lirio

Norte L. F. in Panama.

Diagnosis. Floridatraguline that differs from Aguascalientia and Floridatragulus in having a relatively shorter diastema posterior to p1, more distinct paraconule on P2, higher crowned molars, and distinct protostylids reaching the occlusal surface on lower molars. Further differs from Aguascalientia in having relative larger size. Further differs from Floridatragulus in lacking a p2-p3 diastema. Further differs from Oxydactylus longipes in having a maxillary transverse constriction posterior to P1, relatively more

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reduced premolars, and I3 slightly larger than C1. Further differs from Oxydactylus,

Australocamelus, Gentilicamelus and Tanymykter in having a double enamel loop on the talonid of m3, and an incomplete cingulum on P3. Further differs from Tanymykter in having a weaker maxillary constriction posterior to P1, I3 larger than C1, p4 lacking a transversely expanded paraconid, shorter p1-p2 diastema, and more brachydont molars. Differs from Michenia in having a more brachydont dentition and a caniniform

(rather than incisiform) I3.

Floridatragulinae gen. et. sp. nov.

Figure 3-10 to 3-15, Table 3-3

Holotype. UF 280670, partial skull and associated mandibles with Rp4-m1, Rm3,

Lp4-m1 and partial symphysis from Lirio Norte locality (YPA024), Lirio Norte L. F.

(Rincón et al., 2015; Bloch et al., 2016).

Referred specimens. UF 280452, right P1; UF 280214, right P1; UF 280729, right

P4; UF 280859, right M1-M2 (partial); UF 257197, right M2; UF 246857, right M3; UF

280920, right M3; UF 246825, right M3; UF 280937, right M3; UF 275483, left P1; UF

275483, left P1; UF 280900, left P3; UF 280738, left P4; UF 280970, left P4; UF

275291, left M1; UF 281472, left M2; UF 281477, left M2; UF 245602, left M3; UF

271620, left M3; UF 275168, left partial mandible with m2-m3; UF 271622, right m2; UF

271627, right m2; UF 275195, right m3; UF 257196, right m3; UF 280968, left m1; UF

281476, left m3.

Distribution. Only known from early Miocene (Late Arikareean) sequences from the Panama Canal basin.

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Locality and horizon. Early Miocene (~21 Ma) ash falls from the Las Cascadas

Formation equivalent to the late Arikareean Lirio Norte L. F. in the Panama Canal basin

(Rincón et al., 2015; Bloch et al., 2016) (Figure 1-2).

Diagnosis. As for the genus.

Description

Skull. UF 280670 includes a partial skull and associated mandibles with right I3-

M3; left P1-M3; left right p4-m1, right m3, left p4-m1 and partial symphysis. The partial skull (Figure 3-10, 3-11, 3-12) includes the nasals, frontals, maxillae, partial premaxillae, partial right jugal, and associated isolated cranial fragments. Intense deformation affected the posterior part of the skull. The occipital condyle and the left jugal, the basioccipital, the foramen magnum, the alisphenoid, the squamosal, the pterygoid, and the auditory region were not preserved.

The skull of Floridatragulinae gen. et. sp. nov. from Panama has a distinctive long facial region. The medial length of the nasal bones (Figure 3-12) represents about

130% the P2-M3 APL. The length of the cheekteeth arcade is 75 mm (Table 3-1). There is a distinctive medial constriction of the maxillae at the level of the P1 (Figure 3-11).

The transverse width between C1s measured at the lingual end of the alveoli is approximately 20 mm and is ~20% larger than between the anterior roots of P1. This medial constriction of the maxillae reaches a maximum at the midpoint between the P1 and the P2. The P2 is separated from the P1 by a short diastema that is similar to the

P4 APL (Figure 3-11). The ventral border of the maxilla is fashioned by a distinct sharp ridge that runs anteroposteriorly between the anterior dentition. This ridge is distinct between the P1 and P2 but faint between the C1 and I3. The anterior portions of the premaxillae are not preserved, yet their sutures with the maxillae can be seem on lateral

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view (Figure 3-10). Sutures run from the posterior end of the alveoli of the I3s reaching the nasals dorsally approximately above the P2 (Figure 3-12).

The medial suture of the nasals is ~102 mm long (Figure 3-12). The posteromedial suture between nasals and frontals is distinct and it is located above the anterior root of the M1 on the sagittal plane. The nasals have a relatively wider posterior end (~34 mm) and an anterior end that is extremely narrow reaching a width of ~10 mm above the C1-

P1 diastema (Figure 3-10). The suture between the premaxilla and maxilla meets the nasals dorsally approximately above the posterior root of the P2. The posterior suture between the nasals and the frontals is V-shaped, while the anteriormost tip of the nasal is W-shaped and is located dorsally above the I3. Both nasals run parallel anterior to the

P4 (maximum width ~ 18 mm) but diverge from the sagittal plane posterior to the M1, reaching a maximum of ~38 mm in the widest point (approximately above the anterior root of the M1) (Figure 3-12). A distinct lacrimal vacuity seems to be located between the posterolateral end of each nasal, on the anterior part of the lacrimal, the anterolateral expression of the frontals, and the posterodorsal end of the maxilla (Figure

3-10). The dimensions of this vacuity cannot be estimated accurately; however, a shallow supramaxillary fossa seems evident despite the intense deformation. The maxillary fossa appears to be shallow and confined to the maxillae. It lacks distinct posterior, dorsal, and ventral rims and the presence of a buccinator fossa immediately beneath the nasals cannot be confirmed.

The frontals are rhomboidal, the estimated maximum width is ~90 mm dorsal to the orbit, while the anteroposterior length is ~64 mm on the medial suture between the right and left frontals. There is a distinct foramen in each frontal located ~20 mm

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posterior to the medial suture with the nasals (Figure 3-12). The lacrimal is better preserved on the right side of the skull (Figure 3-10). Each lacrimal is tapered ventrally by the jugal, anterodorsally by the lacrimal vacuity, and anteroventrally by the lateral end of the frontals. The lacrimal makes up the anterior part of the orbit and exhibits a distinctive tuberosity in its posterior margin. Lacrimals have an approximate length of 18 mm anterior to this tuberosity, and have a dorsoventral height of approximately 24 mm.

Despite intense postmortem damage concentrated in the posterior part of the rostrum, a complete postorbital bar is evident posterior to the right orbit in the type (Figure 3-10).

The ventral part of each orbit includes the rostral projection of the malar and the lateral projection of the frontal. Both maxillae are broken yet the infraorbital foramina are located ~11-13 mm above the posterior root of the P4s (Figure 3-10). The suture between the frontal and parietal is not distinct and a distint saggital crest is only partially preserved (Figure 3-10).

Upper dentition. The left I3 is conical, caniniform, and distally recurved (Figure 3-

10, 3-12, 3-13). The APL at the enamel dentine junction is 8.8 mm while the TW is 6.8 mm. The I3 is separated from the C1 by a short diastema equivalent to the P2 APL

(Figure 3-11). No upper canines are preserved, but the size and shape of the alveoli suggest they are smaller than the I3 with distinct circular outlines near the enamel dentine junction. The right P1 is only partially preserved in the type yet the left P1 was found in association. Compared to the dimensions of the alveoli for the C1 and the caniniform I3, the P1 has a relatively low and more elongate (APL>TW) double-rooted crown. The roots are strongly appressed as denoted by a narrow sulcus on the lingual side of the root (Figure 3-13D). The P1 is separated from the P2 by a ~10 mm diastema

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(Figure 3-10B). The P2 is double-rooted and elongate (APL>TW, Table 3-3). The P2 has a large main cusp (metacone) and a barely distinct metastyle (Figures 3-13, 3-14).

The crown of P3 is elongate (APL>TW) and has three roots with the lingual root located close to the posterolabial root. The crown lacks external ribs, and has a heavily worn but distinct paracone interrupting a discontinuous internal cingulum that widens posteriorly. The parastyle, paracone, and metastyle are aligned, forming a straight labial margin. The anterolingual crescent is low and formed by a distinct cingular segment while the posterolingual crescent is low, narrow, and formed by a small cingular segment that extends lingually from the base of the paracone towards the posterior margin, but which never reaches the lingual part of the base of the metastyle. The upper molars of Floridatragulinae gen. et. sp. nov. are square (APL~TW), brachydont, and have distinct, strong entostyles. In occlusal view, the mesial crest overlaps buccally the distal half of the crown, resulting in a very prominent mesostyle (also evident on advanced wear stages) and a deep recess anterior to at the juncture of the paracone and metacone. Strong ribs extend up each crest from the base of the crown to the tip of both paracone and metacone. The entostyles are located lingually between the anterior and posterior crescents and originate at the base of the crown (Figure 3-13). In molars with little wear, two twinned-segments make up the entostyles making the posterior larger and extending higher apically. The anterior and posterior cingula on the upper molars are stronger on the lingual margins of the crescents. The para- and metastyle are well developed on M1 and M2, but slightly reduced in the M3. The M3 exhibits a posterior segment that is transversely reduced (Figure 3-13).

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Mandible. The holotype includes two paired mandibles with the alveoli for the single-rooted p1s, the double-rooted p2s, Lp3, and the crowns of Lp4-m1 and associated Rp4-m3 (Figure 3-14A-C). Although the morphology of the anterior part of the mandible (including the symphysis) is not clearly preserved, the p1 is separated from the c1 by a diastema of unknown length and from the p2 by a short diastema that is shorter than the length of the p4. The symphysis is completely co-ossified and its posterior edge is located ventral to the anterior root of the p1. There is no diastema between the p2 and p3.

Lower dentition. A complete left p1 is available for description. The crown is transversely compressed, caniniform and single rooted (Figure 3-14D-F). The root is relatively larger and distinctively inflated below the enamel dentine junction (Figure 3-

14D, F). The crown of p4 is oval rather than wedge shaped with a talonid that is relatively less expanded transversely. It has a high and distinct metaconid, a narrow entoconid, and the distal edge of the hypoconid slightly overlaps the metaconid lingually. The anterior cuspid (paraconid) is reduced anteroposteriorly. In occlusal view, the entoconid and hypoconid are connected to the metaconid by two distinctive cristids.

A posteriorly open lake is restricted to the posterior part of the talonid. It has a distinct metaconid (principal cusp) with anterior and posterior cristids connecting it to the entostylid and the paraconid.

The lower molars are brachydont with distinct anterior and posterior fossetids

(Figure 3-14A-C). The p3-p4APL/m1-m3APL ratio is ~0.6 (APL for the lower premolars estimated from alveoli). The lower molars have discontinuous and overlapping internal crests where the metaconid crest remains isolated until middle to late wear stages. The

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ectostylids are distinct and restricted to the basal part of the crown between the protoconid and hypoconid in the m1, but remain low between the hypoconid and hypoconulid on the m3 (Figure 3-7). The parastylids remain distinct on lower molars with middle wear. The lower molars have distinct protostylids connecting the base

(anterolabial) of the crown with the anterior part of the occusal surface (Figure 3-14C).

This enamel structure occurs in all specimens recovered from the Lirio Norte L. F. The distinctive shallow invagination on the talonid of m3 is fashioned by a small conulid located between the two grinding surfaces of the hypoconulid on the occlusal surface

(Figure 3-7, Figure 3-14A). Finally, the posterior closure of the fossetid located on the heel of the hypoconulid occurs during early wear stages.

A short note about the early Miocene oxydactyline camels. Since the original description of the genotype Oxydactylus longipes Peterson, 1904, several early

Miocene camelids have been referred to this genus, now recognized as a wastebasket taxon (Prothero, 1996; Honey et al., 1998). Despite the fact that taxonomists have not agreed to the position of this taxon within Camelidae, “Oxydactylus” represents a grade in camelid evolution (McKenna, 1966; Stevens, 1977) and not a natural group (Honey et al., 1998). Although a taxonomic revision of early Miocene species of Oxydactylus

(sensu Honey et al., 1998) is outside of the scope of this research, oxydactyline camels seem to represent the ancentral basal stock of camelids that served as architectural ancestors to more progressive members of the Camelinae (e.g. Tanymykter, Michenia, and Protolabis) (Honey et al., 1998). Therefore, I provide a list of those morphological characters summarized by Honey et al. (1998) for Oxydactylus: complete dental formula, I3, C1/c1, caniniform. I3 is often as large as, or larger than C1; the distance

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between I3s are equal to or greater than the distance between C1s. P1/p1 are double rooted, low crowned, and P2-P4/p2-p4 are more reduced than in Gentilicamelus and primitive Nothokemas. P3 is relatively elongate and narrow, with a prominent parastyle as in Gentilicamelus, and has a strong internal cingulum, which is usually continuous.

The crowns of p2-p4 are well developed and have strongly lingually inflected paraconids. Cheekteeth are brachydont, although more hypsodont than those of

Gentilicamelus. Intercolumnar tubercles are variably present on upper molars and rare in lower molars. The upper molars have strong external ribs and styles. Paraoccipital process is located at the same level or above the occlusal surfaces of the upper molars.

Auditory bullae are relatively less inflated for the size of skull than in Poebrotherium and

Gentilicamelus; bullar compression is less extreme than in miolabines. The maxillary fossa is shallow to deep but not pocketed with the maxilla depressed immediately beneath the nasal. The lower border of the mandible is relatively flat in contrast to

Aepycamelus but slightly concave just in front of the ascending ramus. Cervical vertebrae are long with elongation greatest in the third cervical. Limbs are elongate and slender. Metapodials are unfused and longer than the basal length of the skull.

Metacarpal length is equal or slightly shorter than metatarsal length. The distal articular surface of the proximal phalanx is usually only slightly expanded dorsally with a symmetrical upper surface. Ungual phalanges are high, narrow, and pointed.

Oxydactylus is relatively smaller than Aepycamelus, with more brachydont and less massive dentition (Honey et al., 1998).

The recognized species of this genus are: Oxydactylus longipes from early

Hemingfordian to Bartovian fossiliferous sequences in Baja California (Ferrusquia-

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Villafranca, 1984), late Arikareean-early Hemingfordian Upper Harrison Beds ( =

“Marsland Formation”) in Nebraska; the early Hemingfordian Morava Ranch Quarry and

Niobrara Canyon L. F. in Nebraska (Marsland Formation), and late Arikareean Belmont

Park Ranch L. F. in Montana; Oxydactylus campestris from ealy late Arikareean

Harrison Fauna in Nebraska; O. longirostris from the Runningwater Formation

(Hemingfordian NALMA) in Nebraska; O. benedentatus from the early Hemingfordian

Garvin Farm Local Fauna in Texas; O. wyomingensis from early late Arikareean

Harrison Formation in Wyoming; O. lacota from early Hemingfordian sequences of the

Rosebud Formation in South Dakota (Matthew and Macdonald, 1960; Honey et al.,

1998).

Comparisons

Compared to Poebrotherium sp. from the Orella Member in Nebraska (UF

216914), the skull of Floridatragulinae gen. et. sp. nov. from Panama is about 22% larger and has a distinctively longer facial region that is more similar to that of

Oxydactylus longipes. The medial length of the nasal bones in Floridatragulinae gen. et. sp. nov represent about 130% the P2-M3 APL paralleling the proportions observed in the type of O. longipes. In the type of Tanymykter brachydontus, the medial length of nasal is approximately similar to the P2-M3 APL (Honey and Taylor, 1978). The cheekteeth arcade (P2-M3 APL) of Floridatragulinae gen. et. sp. nov is ~22% shorter than that O. longipes (Table 3-3). The medial length of the nasal bones (Figure 3-12) represents about 130% the P2-M3 APL in Floridatragulinae gen. et. sp. nov. from

Panama while this length is comparable to the P2-M3 APL in the type of O. longipes

(Peterson, 1904). In the type of Tanymykter brachydontus, the medial length of nasal is approximately similar to the P2-M3 APL (Honey and Taylor, 1978).

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In contrast to the type of O. longipes and Poebrotherium sp. from Nebraska, a distinctive medial constriction of the maxillae at the level of the P1 is present in

Floridatragulinae gen. et. sp. nov. (Figure 3-11). This medial constriction of the maxillae, which reaches a maximum at the midpoint between the P1 and the P2, could be in part correlated with the deepening of the buccinator fossa, a morphological character not evident in the badly crushed skull. The P2 is separated from the P1 by a short diastema that is comparable to the P4 APL (Figure 3-11).

The maxillary fossa of the type of Floridatragulinae gen. et. sp. nov., if present, is much shallower and lacks well-defined posterior dorsal and ventral rims of Tanymykter brachydontus in a similar fashion than the type of O. longipes. The lacrimal in

Floridatragulinae gen. et. sp. nov. from Panama is more anterioposteriorly reduced than that of Poebrotherium sp. but similar in proportions to the lacrimal of the type of

Oxydactylus longipes (Peterson, 1904). The ventral part of the orbit includes the rostral projection of the malar bone and the lateral projection of the frontal in the same fashion observed in O. longipes.

Similar to O. longipes, the I3 of Floridatragulinae gen. et. sp. nov. is conical, caniniform, distally recurved, and separated from the P1 by a short diastema.

Compared with the P2 of Aguascalientia (Figure 3-2D), the crown has a larger main cusp (metacone) and a less distinct metastyle (Figures 3-13, 3-14) while the P3 is ~18% larger than that of Aguascalientia panamaensis (Table 3-3). Similar to F. dolichanthereus (and A. panamaensis), the P3 has a distinct paracone interrupting a discontinuous internal cingulum that widens posteriorly. Although relatively larger

(~15%), and slightly more hypsodont, the upper molars of Floridatragulinae gen. et. sp.

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nov. from Panama are square (APL~TW) and similar in general morphology to those of

A. panamaensis (Table 3-3).

The upper molars of Floridatragulinae gen. et. sp. nov. have distinct strong entostyles similar to those of O. longipes and A. panamaensis (Rincón et al., 2012).

Strong ribs extend up each crest from the base of the crown to the tip of both paracone and metacone on the M1, similar to F. dolichanthereus and O. longipes. However, the entostyles are located between the anterior and posterior crescents and originate at the base of the crown similar to those of A. panamaensis (Figure 3-13). Compared to those of Aguascalientia, the anterior and posterior cingula are stronger on the lingual margins of the crescents.

There is no evidence of the distinctive p2-p3 diastema of Floridatragulus. Although the morphology of the anterior part of the mandible (including the symphysis) is not clearly preserved, similar to that of A. panamaensis, the symphysis is completely co- ossified and its posterior edge is located ventral to the anterior root of the p1.

Nonetheless, Floridatragulinae gen. et. sp. nov. has a relatively deeper mandible below the p4 that is more similar to that observed in the relatively larger O. longipes. The root of the p1 of Floridatragulinae gen. et. sp. nov is relatively larger and distinctively more inflated (Figure 3-14D, F) than that of A. panamaensis, paralleling the morphology of

Tanymykter brachydontus (Honey and Taylor, 1978). The p4 of Floridatragulinae gen. et. sp. nov. is about ~ 13% longer than that of A. panamaensis, yet it is ~12% smaller than that of the type of O. longipes (Table 3-3). The crown is less wedge-shaped than that of Poebrotherium with a talonid that is relatively less expanded transversely. In this aspect, the p4 of Floridatragulinae gen. et. sp. nov. parallels the oval (rather than

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wedge-shaped) occlusal outline of the p4 of Aguascalientia and Floridatragulus. Similar to the p4 of other late Arikareean floridatragulines, the anterior cuspid is more reduced anteroposteriorly and lacks the distinctive lingual cristid of Nothokemas. A posteriorly opened lake is restricted to the posterior part of the talonid. It should be noted that despite being represented by molars in advanced wear stages, the crown of the p4 is more hyposodont than that of A. panamaensis after comparing p4s with similar wear stages (Figure 3-15G-H).

The floridatraguline Aguascalientia further differs from Floridatragulinae gen. et. sp. nov. from the same fossil assemblage (see below) in being ~18% smaller (APL P2-

M3: ~ 60 mm vs. 75 mm for Floridatragulinae gen. et. sp. nov.) and having a stronger anterior cusp on P2. Floridatragulinae gen. et. sp. nov. has less reduced lower premolars than O. longipes as noted by the p3-p4APL/m1-m3APL ratios. The ratio is

~0.6 in Floridatragulinae gen. et. sp. nov. (APL for the lower premolars was estimated based on the distance between alveoli) while it is ~ 0.47 in O. longipes. The lower molars of Floridatragulinae gen. et. sp. nov. are relative wider than those of O. longipes.

The ectostylids on the lower molars are weaker that those of Aguascalientia. In contrast to Floridatragulus dolichanthereus, the parastylids are more developed and remain distinct on lower molars with middle wear. Although not as strong as in younger camelines, protostylids occur in all specimens of Floridatragulinae gen. et. sp. nov. recovered from the Lirio Norte L. F. While protostylids are also present on the lower molars of Hemingfordian O. bendentatus from Texas, the lower molars of

Floridatragulinae gen. et. sp. nov. are approximately 28% smaller (Patton, 1969:138).

Similar to that of Floridatragulus, including the type of F. nanus (TMM 40067-194), the

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m3 of Floridatragulinae gen. et. sp. nov has a distinctive shallow invagination on the talonid that is also present in the the. Furthermore, the m3 of Floridatragulinae gen. et. sp. nov also exhibits a small conulid between the two grinding surfaces of the hypoconulid in early wear stages (Figure 3-7, Figure 3-14A). Similar to especies of

Floridatragulus and the type of A. wilsoni, the posterior closure of the fossetid located on the heel of the hypoconulid occurs during early to middle wear stages whereas the invagination is basally located in the A. panamaensis and A. minuta (Rincón et al.,

2012).

Discussion

The partial skull and associated dentitions of Floridatragulinae gen. et. sp. nov. exhibit the following oxydactyline hallmarks present in the type of Oxydactylus longipes: a complete dental formula; a complete post orbital bar, a P1 that is double-rooted and low crowned; P2-P4/p2-p4 are more reduced than those of Gentilicamelus and primitive

Nothokemas, P3 relatively elongate and narrow, with a low but distinct parastyle, and with a distinct internal cingulum, upper molars with strong external ribs and styles and distinct entostyles, faint to weak ectostylids in the lower molars.

Although the placement of this new camel from Panama is somehow blurred by the lack of resolution within “Oxydactylus”, Floridatragulinae gen. et. sp. nov. further exhibits morphologies only present in floridatraguline camels that include: 1) a double enamel loop on the m3 hypoconulid, 2) a p4 with an oval rather than wedge-shape occlusal outline, 3) a horizontal and strongly fussed mandibular symphysis, and 4) an attenuated rostrum with elongation of the anterior part of the maxillaries. I, therefore, refer this new oxydactyline camelid from the Lirio Norte L. F. to a new genus and

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species of floridatraguline that differs from O. longipes in having less reduced lower premolars, more square lower molars, and having an I3 that is larger than the C1.

The relatively shallow maxillary fossa preserved in the type also suggests that

Floridatragulinae gen. et. sp. nov., although relatively smaller, is a camelid closely related to Oxydactylus longipes while lacking the distinctive p1-p2 diastema of

Tanymykter brachydontus. Although having an I3 that is relatively larger than the C1,

Floridatragulinae gen. et. sp. nov. differs from T. brachyodontus in having a shallower maxillary fossa, a weaker maxillary constriction posterior to the P1, a less continuous cingulum on P3, and a p4 lacking a transversely expanded paraconid.

The partial skull of Floridatragulinae gen. et. sp. nov. preserves some cranial morphologies only known for younger (Hemingfordian) protolabines and camelines. A more distinct maxillary constriction posterior to the P1 is present in early Hemingfordian protolabines (e.g. T. brachiodontus) and becomes extreme in derived protolabine forms such as Protolabis (Honey et al., 1998). The weak developed maxillary fossa of

Floridatragulinae gen. et. sp. nov. is a morphological feature present in the early

Miocene camelines (Honey and Taylor, 1978) while the weak protostylids on lower molars are present in early Hemingfordian O. benedentatus from Texas (Patton, 1967;

Patton, 1969:36) and T. brachydontus from Oregon and Wyoming (Honey and Taylor,

1978). Floridatragulinae gen. et. sp. nov. differs from Michenia in having more brachydont and more square molars, a caniniform I3, and stronger ectostylids on lower molars. The m3 of Floridatragulinae gen. et. sp. nov. differs from that of early

Hemingfordian O. benedentatus in having a hypoconulid lobe with two grinding surfaces and smaller size. Despite being more hypsodont than A. panamaensis, the crown of the

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p4 of Floridatragulinae gen. et. sp. nov. exhibits the typical floridatraguline morphology

(oval rather than wedgeshaped occlusal outline) but lacks the distinctive lingual stylids of Nothokemas. Finally, Floridatragulinae gen. et. sp. nov. shows evidence of an increasing hypsodonty, in this aspect paralleling the mesodont parahipine equid found in the same assemblage (Rincón et al., 2014).

Phylogenetic Analysis

To evaluate the phylogenetic relationships of these new early Miocene tropical camelids from Panama I performed a cladistic analysis of 18 camelid taxa from tropical and subtropical areas of North America (including two late Miocene cameline genera, tha cameline Procamelus and the lamine Pleiolama), with the primitive protoceratid

Eotylopus reedi Matthew, 1910 from the Chadronian of Texas and the Great Plains as the outgroup. Because most camelid species found outside the Great Plains are not known from specimens that preserve cranial morphology, I scored more dental (24) than cranial (13) characters (Appendix H). Morphological data were compiled from the study of specimens (casts) housed in the FLMNH collection and a literature review. The data matrix (Appendix G) includes characters that are unordered and equally weighted.

Characters not known for a taxon were coded as missing. Data were compiled in

Mesquite version 2.72 (Maddison and Maddison, 2009) and then analyzed under the parsimony criterion using the branch and bound algorithm of PAUP version 4.0b10

(Swofford, 2003). While I would have liked to include all of the Miocene taxa reported from the Gulf Coast (e.g. Priscocamelus, Australocamelus, miolabines) in my study, many of these camelids are only known from isolated lower dentitions. As consequence, they were excluded from my analysis that resulted in 3 equally most parsimonius

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cladograms (MPT) with a tree length of 75 steps, a consistency index (CI) of 0.533, a retention index (RI) of 0.722, and a homoplasy index (HI) of 0.467.

Results summarized in the consensus tree (Figure 3-16A) consistently support an early Miocene tropical floridatraguline clade (Node 13) with Floridatragulinae gen. et. sp. nov. as the basalmost member (Node 12). The Chadronian “Poebrotherium” franki from

Texas appears as the sister taxon of a clade grouping the nothokematines

(Nothokemas and Gentilicamelus) with the camelid from the Buda Local Fauna (Node

3). A monophyletic “Nothokematinae” was recovered (Node 4). The camelid with unknown relationships from the Buda L. F. in Florida (Frailey, 1979; Rincón et al., 2012) appears as the sister taxon of a clade that includes the early Arikareean Gentilicameuls stenbergi (Node 5) from Oregon (Albright, 1999) and the two species of Nothokemas

(Node 6) known from Florida (N. waldropi and N. floridanus). The early Miocene protolabine camels from higher latitudes Tanymykter and Michenia appear as members of a clade (Node 8) with the Clarendonian lamine Pleiolama makennai as terminal taxon

(Node 9). In contrast, Oxydactylus longipes appears as the sister taxon of the

Clarendonian cameline Procamelus sp. from the Love Bend fossil site in Florida (Node

11). Finally, this clade appears as the sister group of early Miocene floridatragulines

(Node 13) with Floridatragulinae gen. et. sp. nov. from Panama as the basalmost member of an expanded Floridatragulinae (Node 12).

The phylogenetic relationships obtained within Floridatragulinae in this topology confirms that: 1) Oxydactylus-like camelids are the sister group of floridatragulines with

Floridatragulinae gen. et. sp. nov. is the basalmost floridatraguline; 2) Aguascalientia is the sister taxon of Floridatragulus; 3) Aguascalientia minuta is the sister taxon of A.

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panamaensis and A. wilsoni; and 4) and Floridatragulus sp. nov from the Centenario

Fauna in Panama is the sister taxon of F. texanus and F. dolichanthereus. The resulting relationships within Floridatragulinae are similar to those previously reported by Rincón et al., (2012) only differing in the inclusion of Floridatragulinae gen. et. sp. nov. as the basalmost member of an expanded floridatraguline clade. Despite that the relationships between Floridatragulinae gen. et. sp. nov. and floridatragulinae are only supported by one unambiguous synapomorphy [5(2), entoconulid projection reaching the posterior side of heel on m3], my analysis confirms that some of the floridatraguline morphologies

(double loop on the m3 hypoconulid, presence of ectostylid on lower and entostylids on upper molars) initially included in the diagnosis of the subfamily by Maglio (1966) are present in the late Arikareean Oxydactylus-like camelid Floridatragulinae gen. et. sp. nov. My analysis also suggests that a camelid closely related to Gentilicamelus

(Camelidae incertae sedis Frailey, 1979) from the early Arikareean Buda L. F. might represent the ancestral stock that gave rise to Nothokemas as a product of a late

Oligocene camelid radiation in peninsular areas of Florida (Node 4). Although this analysis is the first attempt to resolve the relationships of floridatragulines by incorporating many of the late Arikareean camelid taxa from the Gulf Coast in a phylogenetic approach, it seems clear that floridatraguline ancestry is not linked to small poebrotheres that colonized tropical areas of North America during the Eocene (e.g. “P”. franki) as suggested by Stevens (1969); instead, floridatraguline ancestry is linked to higher latitude Oxydactylus-like camelids that colonized tropical areas of southern North

America during the earlier stages of volcanic and tectonic activity that shaped the tropical landscape during the late Paleogene (Arikareean NALMA). More importantly,

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the relationships obtained between protolabines, Oxydactylus longipes, and primitive member of the tribes Camelini and Lamini (Nodes 7, 8, 10, and 11), although must be regarded as preliminary, suggest that camelines might have had an early Miocene origin, and furthermore, their apparence on the North American fossil record can be linked to the diversification of Arikareean camelids during intense periods of tectonic and paleobiogeographic change during the earliest Miocene. Consequently, basal member of the tribes Camelini and Lamini might have been already differentiated as early as the latest Arikareean based on the early Hemingfordian occurrence of

Oxydactylus longipes and Tanymykter brachydontus (Peterson, 1904). This is an interesting outcome that needs to be researched further given the clear resemblances observed between the dentitions and skulls of the primitive floridatraguline

Aguascalientia and late Miocene camelines (e.g. elongate rostrum, caniniform p1/P1, ventral border of the symphysis with a strong crest). Unfortunately, the resolution of my analysis did not allow the definition of unambiguous synapormorphies to reinforce any statement regarding the ancestral relationships of these late Miocene cameline genera.

As mentioned earlier, inclusion of the miolabines in my analysis was not possible; hence, the relationship between early Miocene (Hemingfordian) miolabines from the

Gulf Coast and other tropical camelids only can be achieved after a detailed phylogenetic analysis incorporating all the cranial morphologies of the late Arikareean and Hemingfordian camelids from southern North America. However, it seems plausible that the ancestry of these hypsodont camelids lacking the anterior premolars (p1 and p2) can be traced back to an Oxydactylus-Miolabis intermediate (Honey et al., 1998) likely also restricted to the Gulf Coast. Once the taxonomic revision of oxydactylines is

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utterly achieved, the hypotheses regarding the evolution of early Miocene miolabines will be clarified as well as the proposed affinities of the late Arikareean Priscocamelus wilsoni from Texas with younger camelines (Stevens, 1977).

Late Oligocene to Early Miocene Higher Camelid Paleobiogeography in Southern North America

The late Arikareean (~21 Ma) occurrence of a basal floridatraguline

(Floridatragulinae gen. et. sp. nov.) in volcanic tropical areas of Panama highlights a remarkable paleobiogeographic pattern for early Miocene Oxydactylus-grade camelids.

Including the type of Oxydactylus longipes, late Arikareean oxydactylines are only reported from volcanic sequences along the active margin of North America (Peterson,

1904; Woodburne et al., 1974; Whistler and Lander, 2003). In contrast, oxydactylines are not recorded in cratonic sequences from the Central Plains and the coastal plain of

Texas until the earliest Hemingfordian (Honey et al., 1998; Patton, 1969). This pattern, although likely biased by taphonomic factors (erosion or non-deposition) but not by sampling intensity, suggests that oxydactylines inhabited more open (volcanic) habitats during the late Arikareean and only colonized more closed habitats of the Central Great

Plains and the coastal plain (Gulf Coast) until the Hemingfordian. This observation, here initially regarded as preliminary given the lack of additional detailed paleoecological studies in the Gulf Coast, is further supported by the early Miocene paleobiogeography of the basal floridatragulines Floridatragulus and Aguascalientia. These two small camelids have biostratigraphic ranges that overlap (Rincón et al., 2012), but have never been found in the same assemblage. Furthermore, these similarly sized floridatragulines (with elongate skulls and brachydont dentitions) likely inhabited similar niches along the same paleobiogeographic province. Nonetheless, the lithostratigraphic

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context of their occurrences confirms that each genus, instead, inhabited specific ecosystems. Among these early Miocene floridatragulines with elongate rostra, the relatively shorter-snouted Aguascalientia inhabited highly perturbed volcanic terrains as denoted by occurrences in the Arikareean Lirio Norte L. F. (Chorotega block) and the

Castolon L. F. in Texas (Tertiary volcanic rocks of Sierra Madre Occidental), and the

Hemingfordian (Zoyotal L. F.) sequences from the Tepehuano terrain in southern

Mexico (Dengo, 1985; Stevens, et al., 1977; Sedlock et al., 1993). In contrast, the relatively longer-snouted Floridatragulus inhabited karstic and coastal environments with low relief in Texas, Florida, and Panama during the Hemingfordian and Barstovian

NALMAs (Patton, 1969; White, 1940; Rincón et al., 2015) with no record of this genus in fossiliferous volcanic sequences in western North America. Furthermore, floridatragulines have not been found in any early late Arikareean assemblage in the

Gulf Coast plain (e.g., Toledo Bend), nor any late Arikareean assemblage in Florida where nothokematines were the only camelids.

Additional evidence supporting these interpretations can be extracted from the late

Arikareean mammalian paleobiogeography in areas of the northern Gulf Coast. Similar to the Lirio Norte L. F., the early to late Arikareean Toledo Bend and the Cedar Run faunas in Texas include ungulate genera reported in the Great Plains that are not known from any other Arikareean assemblage in the Gulf Coast Plain (e.g. the anthracothere Arretotherium and parahippine horses) (Albright, 1998). Although camelids are rare in these assemblages, the presence of riparian species (e.g. tapiroids, anthracotheres) suggests that the valley of the ancient Mississippi River, in addition to being a corridor connecting the Gulf Coast with the Central Plains, might

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have also operated as a barrier for ungulates during the middle Arikareean, only allowing the dispersal of generalist (bunodont and bunoselenodont) artiodactyls like entelodonts and peccary “Cynorca” (Albright, 1998; Tedford et al., 2004; O’Sullivan,

2003). The presence of middle Arikareean congeneric species of Dapheonodon and

Nanotragulus in both the Gulf Coastal Plain and the Great Plains confirms that these two provinces were ecologically distinct (Albright, 1998). Furthermore, this distinction may have begun only slightly earlier (middle Arikareean) as denoted by endemic Gulf

Coast forms in Florida (nothokematines) and Texas (Gentilicamelus-like camelids), and oxydactyline camelids that led to late Arikareean tropical endemic taxa (e.g. floridatragulines) in southern North America (Rincón et al., 2012).

Consequently, a Gentilicamelus-like camelid, closely related to Nothokemas, entered Florida during the early Arikareean. Although never formally described, the relationships of this camelid, only known from partial dentitions, have remained unclear since their original description in the Buda L. F. by Frailey (1979). By the late early

Arikareean the provincialism along southern North America intensified. Nothokematines thrived in Florida while Gentilicamelus-like camelids inhabited the subtropical and volcanic terrains associated to the active margin in western North America (Texas) with no camelid occurrences in areas of the ancient Mississipi Valley. By the late Arikareean, nothokematine camels became the most common camelids in Florida, while oxydactylines (O. benedentatus), Gentilicamelus–like camelids (Priscocamelus,

Delaxomeryx), and floridatragulines were also present in Texas (Aguascalientia sp.) and

Panama (Aguascalientia and Floridatragulinae gen. et. sp. nov.). Surprisingly,

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stenomyline camels, the most common camelids elsewhere during the Arikareean have not been reported from any of the late Arikareean asemblages from Florida or Panama.

By the earliest Hemingfordian (c.a 19 Ma), provincialism weakened and floridatragulines were then well represented in the Gulf Coast (Miller Site L. F. and

Thomas Farm sites in Florida as well as the Garvin Gully L. F. in Texas), and Panama

(Centenario Fauna). By the late Miocene (Barstovian and Clarendonian NALMAs), ungulates with early Miocene origins in tropical areas of North America (e.g. the protoceratine Paratoceras and also Floridatragulus) are present in the coastal plains habitats on the passive margin likely exploiting a northwardly expanding Neotropical woodland savanna environment (Albright, 1998).

Discussion

Two new floridatraguline camelid species are reported from early Miocene assemblages in Panama: the small floridatraguline Floridatragulus sp. nov. from the early Hemingfordian Centenario Fauna, and the basal floridatraguline Floridatragulinae gen. et. sp. nov. from the late Arikareean Lirio Norte L. F. Based on the morphological variation observed in the m3s from early Miocene camelid populations in the Gulf Coast and Panama, the species F. nanus Patton, 1969 is a nomen dubium. Nevertheless, the early Hemingfordian occurrences of small species of Floridatragulus in tropical (Lat ~9

N) and subtropical (Lat ~25-30 N) sequences from Texas and Florida ratify an early

Hemingfordian faunal province connecting passive margin terrains of the Gulf Coast with tropical areas of Panama.

Floridatragulinae gen. et. sp. nov. represents the earliest occurrence of an oxydactylus-grade camelid in the tropics of North America and the basalmost floridatraguline camel. Although lacking the distinct p1 with relatively longer anterior and

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posterior diastemata of other floridatragulines, Floridatragulinae gen. et. sp. nov. exhibits morphologies (hypoconulid lobe on m3 with two grinding surfaces, entostylids on upper molars and ectostylids on lower molars) herein interpreted as synapomorphies for floridatragulines that are not present in any of the other early Miocene camelid subfamilies in North America (Maglio, 1966). Furthermore, the partial skull of

Floridatragulinae gen. et. sp. nov. exhibits morphologies that suggest a link to

Oxydactylus longipes, namely, I3 larger than C1, elongate rostrum, P1 double rooted and low crowned; entostyles on upper molar and ectostyilid on lower molars variable present, and a shallow maxillary fossa (Honey et al., 1998). Moreover, Floridatragulinae gen. et. sp. nov. exhibits cranial (rostral constriction posterior to the P1) and dental morphologies (a low-crowned p1 with strongly appressed roots) only present in younger

(late early Miocene) protolabidines like Tanymykter. Although a thorough systematic review of the early Miocene oxydactylines will clarify the relationships between

Floridatragulinae gen. et. sp. nov. and other tropical camelid lineages such as miolabines and younger (late Miocene) camelines, the occurrence of an Oxydactylus- grade floridatraguline camel in late Arikareean fossil assemblages from Panama suggests that: 1) Oxydactylus-grade camelid dispersed into the tropics by gradually colonizing volcanic terrains of western North America during the late Arikareean; 2) by the latest Arikareean and early Hemingfordian NALMAs, descendants of this

Oxydactylus-grade ancestor were already differentiated and represented by three floridatraguline genera: Floridatragulinae gen. et. sp. nov. from Panama, Floridatragulus and Aguascalientia. This interpretation confirms that basal floridatragulines underwent a rapid taxonomic radiation during the late Arikareean in tropical areas before they

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became ecologically important in areas of the Gulf Coast during the Hemingfordian.

Furthermore, the stratigraphic and paleogeographic distribution of Aguascalientia and the older species of Floridatragulus confirms a new paleobiogeographic hypothesis where the northward spread of ungulate communities occurred only after taxonomic diversification was achieved in tropical areas of southern North America. In fact, now that the floral composition of the early Miocene Panamanian forest is known (Jaramillo et al., 2014), it seems reasonable to hypothesize that this forest was a completely novel niche for these ungulates. This favored diversification processes (cladogenesis) by offering novel food resources, while also limiting the dispersal capability of allocthonous specialized herbivores (e.g. South American platyrrhine monkeys) into higher latitudes.

Independent of the results of the ongoing paleobotanical work, selenodont artiodactyls clearly were subjected to different selective pressures than those operating in higher latitudes and diversified rapidly just after colonizing tropical forests dominated by floras with South American affinities.

The early Miocene Panamanian fossil record confirms that the mammalian disparity observed in southern North America was at a maximum during the late

Arikareean as denoted by strong provincialism between the coastal plain sequences of the Gulf Coast and the volcanic sequences from Panama (Lirio Norte L. F.) and Texas

(Castolon L. F.). Early Late Arikareean assemblages from Texas (e.g. the Toledo Bend

L. F and the Castolon L. F.), similarly to Panama, include the ocurrence of endemic ungulates like basal parahippine horses (Albright, 1999; Rincón et al., 2014) and the floridatraguline Aguascalientia (Stevens, 1969), while the peninsular areas of Florida were inhabited by camelids with distinctive more gracile mandibles, the nothokemathine

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Nothokemas (Frailey, 1978). In contrast, the earlyHemingfordian is characterized by weakened provincialism that favored the rapid dispersal northwards of late Arikareean tropical endemic taxa such as Aguascalientia, Floridatragulus, and other selective browsers such as protoceratine protoceratids (Rincón et al., 2015). This dispersal of newly evolved tropical taxa might have only been permitted as Neotropical woodland savanna environments allowed access to the Gulf region soon after the earliest

Hemingfordian NALMA (Albright, 1998). Finally, regardless of whether this event resulted in the dwindling and eventual extinction of the late early Miocene Gulf Coast browsing fauna and its replacement by more hypsodont, mixed-feeding herbivores, a late early Miocene (Barstovian NALMA) continuity between northern (Great Plains) and southern faunas in the Gulf Coast is clear (Albright, 1998). However, the colonization of low land environments along the passive margin of North America (Gulf Coast) during the Hemingfordian was only achieved when camelids with a more temperate ancestry gained important morphological adaptations (elongation of the rostrum, and a relatively long and narrow fused symphysis) which would have allowed them to exploit the novel and denser forested habitats developed in southern North America and the Gulf Coast.

In order to define a better and more plausible paleobiogeographic scenario, the floral and faunal composition of early Miocene tropical and subtropical assemblages must be integrated in a more detailed paleoecological model.

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Figure 3-1. Location and biochronology of the Oligocene-Miocene camelid-bearing fossil faunas discussed in this study. 1, Floridatragulus dolichanthereus from the Hemingfordian Thomas Farm site in Florida (White, 1940); 2, 3 Floridatragulus texanus from the Barstovian Trinity River Fauna in Texas (Patton, 1969); 4, Floridatragulus hesperus from the late Barstovian Cold Spring Local Fauna in Texas; 5, Floridatragulus nanus from the Early? Hemingfordian Garvin Gully L. F. in Texas; 6, Floridatragulus sp. nov (this study) from the late Arikareean-early Hemingfordian Centenario Fauna in Panama (MacFadden et al., 2014); 7, Aguascalientia spp. from the Late Arikareean Lirio Norte L. F. in Panama (Rincón et al., 2012; 2015); 8, Aguascalientia wilsoni from the early? Hemingfordian Zoyotal L. F. in Mexico (Stevens et al., 1969); 9, Delahomeryx browni, Priscocamelus wilsoni, and Aguascalientia sp. from the late Arikareean Castolon L. F. in Texas (Stevens et al., 1969; Stevens, 1977); 10, Nothokemas waldropi from the early Arikareean SB-1A L. F. in Florida (Frailey, 1978); 11, Gentilicamelus stenbergi from the early-Middle Arikareean Turtle Cove Member, in Oregon (Albright et al., 2008); 12, Camelidae incertae sedis from the early-late Arikareean Buda L. F. in Florida (Frailey, 1979; Tedford et al., 2004); 13, Oxydactylus longipes from the early? Hemingfordian Upper Harrison Formation in Oregon (Peterson, 1904). Chronostratigraphy and biochronology modified from Albright et al. (2008). Abbreviations: A, Aguascalientia Ar, Arikareean NALMA; Ba, Barstovian NALMA; Cl, Clarendonian NALMA; D, Delahomeryx; E, early; F, Floridatragulus; G, Gentilicamelus; He, Hemingfordian NALMA; L, late; L. F., Local Fauna; N, Nothokemas; O, Oxydactylus; P, Priscocamelus.

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Figure 3-2. Partial rostrum of Aguascalientia panamaensis Rincón et al., 2012 from the Lirio Norte L. F. UF 281478, partial skull with partial maxillae, partial nasals, RC1-P4, LC1 (partial) and Lp2. A, UF 281478, right and left nasals, dorsal view; B, UF 281478, right nasal, lateral view; C, UF 281478, partial right maxilla, lateral view; D, UF 281478, right and left maxillae, ventral view; E, UF 281478, right C1, lingual view; F, UF 281478, right C1, occlusal view; G, UF 281478, right C1, labial view; H, UF 281478, right P1, lingual view; I, UF 281478, right P1, anterior view; J, UF 281478, labial view. Abbreviations: Io, infraorbital foramen; Pa, Paracone; Pst, Parastyle. Arrows point anterolingually.

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Figure 3-3. Upper permanent and deciduous dentition of Floridatragulus sp. nov from the early Hemingfordian Centenario Fauna. A, STRI 38902, right P3, occlusal view; B, STRI 38902, right P3, lingual view; C, STRI 38902, right P3, labial view; D, UF 280023, left M2, occusal view; E, UF 280023, left M2, lingual view; F, UF 280023, left M2, labial view; G, UF 246853, right DP3-M1, occlusal view; H, UF 246853, right DP3-M1, lingual view; I, UF 246853, right DP3-M1, labial view. Arrows point anterolingually.

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Figure 3-4. Holotype of Floridatragulus sp. nov from the Centenario Fauna. UF 267194, partial left mandible with p4-m3. A, occlusal view; B, labial view; C, UF 267194, associated Rp4, occlusal view; D, UF 267194, associated Rp4, lingual view; E, UF 267194, associated Rp4, labial view; F, UF 267194, associated Rm3, occlusal view; G, UF 267194, associated Rm3, lingual view; H, UF 267194, associated Rm3, labial view. Arrows point anterolingually.

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Figure 3-5. Holotype of Floridatragulus sp. nov from the Centenario Fauna. A, UF 267194, Lp2, occlusal view; B, UF 267194, Lp2, labial view; C, UF 267194, Lp2, lingual view; D, UF 267194, Rp3, occlusal view; E, UF 267194, Rp3, lingual view; F, UF 267194, Rp2, labial view. Arrows point anterolingually.

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Figure 3-6. Detailed view of the symphysis and the rooth of p1 of Floridatragulus sp. nov. A, UF281137, partial symphysis with alveoli for c1s and p1s, occlusal view; B, UF281137, partial symphysis with alveoli for c1s and p1s, labial view; C, UF281137, detailed view of the roots of Rp1, oblique view.

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Figure 3-7. Morphological variation on lower m3s from different populations of early Miocene higher camelids from southern North America. A, UF 271595, partial mandible with Rm2-m3 (p4 not figured) of Floridatragulus sp. nov from the early Hemingfordian Centenario Fauna in Panama, occlusal view; B, UF 271595, partial mandible with Rm2-m3, lingual view; C, UF 271595, partial mandible with Rm2-m3, labial view. D, TMM 40067-194, holotype of Floridatragulus nanus from the Garvin Gully L. F. in Texas, occlusal view; E, TMM 40067-194, type of F. nanus from the Garvin Gully L. F. in Texas, lingual view; F, TMM 40067-194, type of F. nanus from the Garvin Gully L. F. in Texas, labial view; G, UF 280670, Lm3, type of Floridatragulinae gen. et. sp. nov. from the Late Arikareean Lirio Norte L. F. in Panama, occlusal view (see also Figure 3-14); H, UF 7185, Rm3 of Floridatragulus sp. from the early Hemingfordian Thomas Farm Fauna in Florida, occlusal view. Abbreviations: ptsd, protostylid. Arrows point anterolingually.

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Figure 3-8. Metatarsus of Floridatragulus sp. nov. from the Hemingfordian Centenario Fauna in Panama. A, UF257204, left complete metatarsal, anterior view; B, posterior view; C, mesial view; D, proximal view; E, distal view.

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Figure 3-9. Variation in tooth dimensions (in natural log scale) observed in higher fossil camelids from North America. A, scatterplots of the dental dimensions of lower m1s measured in early Miocene camelid populations from the Gulf Coast and Panama; B, box plots representing the variation observed in the lower m3 dimensions measured for different populations of camelids from the Gulf Coast and Panama (See Appendices D and E).

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Figure 3-10. CT scan surface model of the skull of Floridatragulinae gen. et. sp. nov. (UF 280670) from the Lirio Norte L. F. in Panama. A, right maxilla with P2- M3, occlusal view; B, labial view; Abbreviations: Frt, Frontal; Io: Infraorbital foramen; Lac, lacrimal; Mal, mallar; Max, maxillary; Nas, nasal; Pmax, premaxilla.

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Figure 3-11. Detailed view of the anterior part of the skull of Floridatragulinae gen. et. sp. nov. from the Lirio Norte L. F. showing the distinctive maxillary constriction posterior to the P1 present in UF 280670.

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Figure 3-12. Dorsal detailed view of the skull of Floridatragulinae gen. et. sp. nov. from the Lirio Norte L. F. UF 280670, dorsal view. Abbreviations: Nas, nasal.

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Figure 3-13. Upper dentition of Floridatragulinae gen. et. sp. nov. from the Lirio Norte L. F. A, UF 280670, partial skull in dorsal view from the Las Cascadas Formation, Panama; B, associated upper RP1, anterior view; C, associated upper RP1, labial view; D, Floridatragulinae gen. et. sp. nov, associated upper RP1, lingual view. Abbreviations: Io: Infraorbital foramen.

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Figure 3-14. Lower dentition of Floridatragulinae gen. et. sp. nov. from the late Arikareean Lirio Norte L. F. in Panama. A, UF 280670, paired mandibles with Rp4-m1, Rm3, Lp4-m1 and partial symphysis, occlusal view; B, UF 280670, lingual view; C, UF 280670, labial view; D, UF 280670, Lp1, labial view; E, UF 280670, Lp1, occlusal view; F, UF 280670, Lp1, lingual view; G, UF 280670, Lp4 of Floridatragulinae gen. et. sp. nov. (holotype) in labial view; H, Lp4 pf Aguascalientia panamaensis from the same locality. Note the difference in crown height in p4s with comparable wear stages. Abbreviations: ptsd, protostylid.

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Figure 3-15. Hypothetical relationships of the early Miocene camelids from tropical and subtropical Central America based on a 37-character matrix with Eotylopus reedi as the outgroup. Strict consensus tree resulting after the analysis under the parsimony criterion using the branch and bound algorithm of PAUP version 4.0b10 (Swofford, 2003) (Tree length = 75; CI = 0.533, RI = 0.722, HI = 0.466); Abbreviations: Ar, Arikareean North American Land Mammal Age (NALMA); Ba, Barstovian NALMA; Ch, Chadronian NALMA; Cl, Clarendonian NALMA; Du, Duchesnean NALMA; He, Hemingfordian NALMA; Or, Orellan NALMA; Ui, Uintan NALMA; Wh, Whitneyan NALMA. At each node (bold numbers) the supporting unambiguous synapomorphies are: 1, Camelidae; 2, (1[1]), (33[1]), (34[1]); 3, (11[1]); 4, (5[1]); 5, “Nothokematinae”, (30[1]); 6, (3[1]), (7[1]); 7, (15[1]); 8, (28[1]), (7[1]); 9, (15[1]); 10, (21[1]); 11, (14[0]*), (17[1]*); 12, Floridatragulinae (5[2]); 13, (12[1]), (16[1]), (20[1]), (23[1]); 14, (8[1]) 15, (32[1] *); 16, (2[1] *). *, Ambiguous.

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Table 3-1. Comparative measurements (in mm) of the camelid skulls from Panama and the Central Plains discussed in this chapter. Poebrotherium Oxydactylus Tanymykter Floridatragulinae Aguascalientia Flordiatragulus

sp. Brule Fm. longipes brachydontus gen. et. sp. nov. panamaensis dolichanthereus Greatest width of skull at postorbital 65 mm 126 mm ~ 77 mm ~ 100 mm NA NA processes Length of the ~82 mm 98 mm 110 mm 105 mm NA NA nasals, median line Length of the maxillae, median ~52 mm ~ 150 mm NA ~125 mm ~70 mm NA line Greatest constriction of palate posterior to NA 20 mm ~21 mm ~ 24 mm ~ 16 mm NA P1 Length of P2-M3 55 mm 102 mm 100 mm ~ 75 mm ~ 60 mm ~80 mm series Distance from Canine to continuous upper ~ 32 mm 40 mm 45 mm ~ 29 mm 30 mm NA premolar-molar series Greatest width of 18 mm ~ 50 mm 48 mm ~38 mm 30 mm NA nasals

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Table 3-2. Summary table of dental measurements (in mm) of Floridatragulus sp. nov. from the late Centenario Fauna (Upper Cucaracha Formation), Panama. Abbreviations: APL, anterior-posterior length; TW, transverse width; TWhyd, hypoconulid transverse width; S, standard deviation; V, index of Variance.

Tooth Position N Range Mean S V

p2 (APL) 1 7.56 7.56 0.44 3.97

p2 (TW) 1 3.31 3.31

p3 (APL) 2 8.06-8.28 8.17 0.155 1.90

p3 (TW) 2 3.37-4.41 3.74 0.523 13.99

p4 (APL) 4 7.19-9.09 7.9 0.844 10.623

p4 (TW) 4 4.52 5.49 0.442 9.16

m1 (APL) 1 10.55 10.55 - -

m1 (TW) 1 9.24 9.24 - -

m2 (APL) 5 12.12-14.60 13.53 1.27 9.38

m2 (TW) 5 10.2-11.27 10.9 0.32 2.98

m3 (APL) 2 18.12-21.08 19.6 2.09 10.66

m3 (TW) 2 10.40-10.67 10.54 0.19 1.88

m3 (TWhyd) 2 6.56-6.85 6.70 0.20 3.05

P3 (APL) 1 8.57 8.57

P3 (TW) 1 4.83 4.83

M1 (APL) 2 9.03-9.53 9.28 0.424 4.41

M1 (TW) 2 9.02-10.02 9.53 0.412 4.32

M2 (APL) 1 11.5 11.5

M2 (TW) 1 11.59 11.59

M3 (APL) 5 10.14-12.05 11.00 0.862 7.86

M3 (TW) 5 10.85-14.3 12.98 1.349 10.39

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Table 3-3. Summary table of dental measurements (in mm) of Floridatragulinae gen. et. sp. nov. from the upper part of the Las Cascadas Formation, Panama. Abbreviations: Alv, measured on alveoli; APL, anterior-posterior length; TW, transverse width; TWhyd, hypoconulid transverse width; S, Standard deviation; V, index of Variance. Floridatragulinae gen. et. sp. nov. Upper Molars

Tooth Position N Range Mean S V

I3 (APL) 1 8.8 8.8

I3 (TW) 1 6.8 6.8

C1 (APL) alv 7.2 7.2

C1 (TW) alv 5.5 5.5

P1 (APL) 1 7.46 7.46

P1 (TW) 1 4.4 4.4

P2 (APL) 2 13.01-13.02 13.02 0.007 0.05

P2 (TW) 2 6.53-6.61 6.57 0.057 0.86

P3 (APL) 4 11.42-13.15 12.65 0.82 6.48

P3 (TW) 4 7.31-8.60 8.01 0.61 7.61

P4 (APL) 5 9.03-9.83 9.41 0.309 3.28

P4 (TW) 5 11.64-12.45 12.00 0.301 2.51

M1 (APL) 6 11.01-11.89 11.45 0.352 3.07

M1 (TW) 6 12.86-13.95 13.41 0.438 3.26

M2 (APL) 5 11.93-12.98 12.44 0.408 3.28

M2 (TW) 5 15.05-16.12 15.68 0.453 2.89

M3 (APL) 4 12.78-13.15 12.85 0.233 1.83

M3 (TW) 4 14.81-16.82 16.03 0.942 5.87

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Table 3-3.Continued

Floridatragulinae gen. et. sp. nov. Lower Molars

Tooth Position N Range Mean S V

p2 (APL) 2 12.13-12.42 12.28 0.205 1.67

p2 (TW) 2 4.30-4.48 4.39 0.127 2.89

p3 (APL) 3 11.96-13.22 12.57 0.631 5.02

p3 (TW) 3 4.94-5.15 5.02 0.116 2.31

p4 (APL) 7 10.05-12.01 11.27 0.583 5.17

p4 (TW) 7 6.19-7.01 6.68 0.311 4.66

m1 (APL) 9 10.57-11.53 11.00 0.354 3.22

m1 (TW) 9 8.08-10.32 9.34 0.476 5.09

m2 (APL) 9 10.88-12.5 11.95 0.524 4.38

m2 (TW) 9 10.16-11.00 10.58 0.344 3.25

m3 (APL) 8 10.43-18.56 17.67 0.789 4.46

m3 (TW) 8 10.67-11.22 10.89 0.196 1.80

m3 (TWhyd) 8 5.99-7.02 6.42 0.318 4.95

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CHAPTER 4 EARLY MIOCENE TAYASSUIDS FROM PANAMA

The diversity of extant and fossil ungulates provides multiple examples of adaptation to different types of herbivory. The extant superfamily Suina (or Suiformes) represents a lineage of omnivorous non-ruminant artiodactyls that include the Suidae

(Eastern Hemisphere, pig family) and Tayassuidae (Western Hemisphere, peccary family) (Spaulding et al., 2009). Despite clear morphological resemblance in the general body plan to other suines (Sowls, 1984), tayassuids represent an endemic, monophyletic group with Paleochoerus as the earliest representative (Simpson, 1930;

Wright et al., 1998). The extant tayassuid genera (Dicotyles, Catagonus and Tayassu) have a distinctive robust cranial morphology characterized by compact skulls with prenatal fusion of cranial bones, strong mandibles with interlocking vertical upper and lower canines to prevent dislocation when chewing tough and/or hard foods, bunodont to zygodont (approaching bilophodont) cheekteeth, forelimbs with four digits, and hindlimbs with three digits. Although relatively smaller than the Euroasian suids, extant peccaries also have a disk-shaped rhinarium (Woodburne, 1968; Kiltie, 1981; Wright,

1998). Dietary studies on extant tayassuids showed preference for cacti, nuts, roots and even animals (Sowls, 1984); however, a clear correlation between tooth morphology and diet has not been achieved. Furthermore, the biogeographic distribution of extant species demonstrates their capability to inhabiting different habitats, ranging from densely forested areas of the New World Tropics (Tayassu pecari) to drier and more open habitats (Dicotyles tajacu and Catagonus wagneri) in sub-tropical areas of North and South America (Woodburne, 1969; Gasparini et al. 2013). Although North American

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tayassuid ancestry is linked to the late Eocene Euroasian Paleochoerus (Wright, 1998), the occurrence of a slightly older and more primitive tayassuid, Egatochoerus jaegeri in

Thailand, suggests that basal tayassuids originated in southeastern Asia (Ducrocq,

1994). Nonetheless, the recognition of a Tayassuidae encompassing both Old and New

World members can only be achieved after the systematics of early members of the

Suidae and Tayassuidae becomes better understood.

Tayassuids are known from North America starting in the late Eocene (Chadronian

North America Land Mammal Age, NALMA), and their presence in South America is only recorded after the beginning of the GABI during the Pliocene (Chapadmalalan

South American Land Mammal Age) (Wright, 1998; Gasparini et al., 2013). The oldest tayassuid in the Western Hemisphere is the late Eocene bunoselenodont Perchoerus minor Cook, 1922, the smallest peccary yet known, which marks the dispersal of tayassuids from Asia (ca. 36 Ma). Most of the known fossils of Perchoerus from the

Great Plains are referred to the relatively larger Perchoerus probus Leidy, 1869 from the latest Eocene (Whitneyan NALMA, ~ 33 Ma) assemblages in the Great Plains (South

Dakota, Nebraska, Colorado, eastern Wyoming), and Oligocene (Whitneyan-Arikareean

NALMAs ~31 Ma) assemblages in Oregon (Woodburne, 1969; Wright, 1998; Prothero,

2009). Thinohyus is also known from Paleogene (Whitneyan-Arikareean) fossiliferous sequences from Oregon (Albright and Woodburne, 2008; Macdonald, 1970; Prothero,

2009).

These basal tayassuids lived in the temperate habitats (~44 N Lat) established in the Great Plains during relatively warmer and wetter conditions ca. 35 Ma prior to the icehouse intervals evidenced in the marine record during the earliest Oligicene ca. 33

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Ma (Oi-1 glaciation) and near the Oligocene-Miocene boundary ca. 23 Ma (Mi-1 glaciation) (Zachos et al., 2001). However, the late Oligocene (~25-27 Ma) occurrence of Simojovelhyus pocitoensis Ferrusquia-Villafranca, 2003 in southern Mexico (~ 17 N

Lat) highlights a remarkable plaeobiogeographic pattern in early tayassuids. This small tayassuid with incipient lophodonty (bunodont) and more inflated cuspids is similar in size to the Chadronian Perchoerus minor from South Dakota and Nevada (Prothero et al., 2015). Furthermore, it was found in sequences representing low land (mangrove) forested habitats (Graham, 1999). Bunodont crowns characterized by short shearing crests on the occlusal surface (therefore large crushing basins for teeth to contact one another) are more efficient in breaking down hard-objects, while crowns with relatively longer and more distinct crests or cristids (more lophodont) are more efficient in processing tough-food (Ungar, 2010). Although only represented by a partial mandible with molars, the occurrence of Simojovelhyus suggests that while more lophodont tayassuids (e.g., species of Perchoerus and Hesperhys) inhabited the more open habitats of the Central Great Plains in the Oligocene, tayassuids from lower latitudes had already acquired a bunodont dentition and, therefore, were coping with the more forested (lowland) habitats of southern North America.

The beginning of the Miocene is marked by drastic changes in the taxonomic composition of the tayassuid populations in the Central Plains. Oligocene bunoselenodont forms like Perchoerus were rapidly replaced by the more progressive bilophodont tayassuids like Herperhys and Thinohyous. In fact, by the latest Arikareean

NALMA (earliest Miocene), tayassuid generic diversity increased in southern North

America and forms with more lophodont dentition (e.g. Floridachoerus) coexisted with

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small bunodont peccaries similar to Marshochoerus socialis (formerly “C”. sociale)

(Albright, 1998; Albright, 1999; Patton, 1969). Although likely affected by sampling intensity in the Gulf Coast and southern North America, this level of sympatry along the

Gulf Coast suggests that bunodont and more lophodont tayassuids inhabited similar habitats in coastal areas during intervals of gradually cooler and drier conditions in the earliest Miocene (late Arikareean NALMA) and, gradually became important components in ungulate faunas in the Gulf Coast. Furthermore, tayassuid groups inhabiting subtropical areas during the late Oligocene colonized the more tropical habitats of southern North America (including the recently formed Panama Canal basin) as drastic changes in temperate habitats gradually occurred in higher latitudes during the earliest Miocene just after the beginning of cooling periods preceding the warmer conditions of the middle Miocene (Woodburne, 1969; Janis, 2002; Graham, 2010). For instance, almost all late Arikareean-early Hemingfordian bunodont tayassuids are reported from transitional to lowland environments (Figure 4-1) throughout North

America with the only exception of a bunodont tayassuid (“Cynorca” sp.) from the late

Hemingfordian Phillips Ranch Fauna in California. The occurrence of this taxon in a paleobiogeographic province in South Western North America characterized by floras representing drier conditions (Madro Tertiary taxa of Axelrod, 1957) supports the notion that these tayassuid populations, similar to the extant peccaries, were already capable of surviving in a variety of habitats. In fact, bunodont tayassuids expanded their ranges throughout North America during the early Hemingfordian NALMA and are recorded in transitional environments on both the West and East Coast of North America (Oregon and Maryland) (Wright and Enshelman, 1987; Emry and Enshelman, 1998). More

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interestingly, the appearance of bunodont tayassuids in the central Great Plains is only recorded during the Barstovian with the occurrence of “Cynorca” sp. (Jacobs, 1998), a relatively warmer period that coincides with the Middle Miocene Climatic Optimum

(Zachos et al., 2001; Holbourn et al., 2007; Zachos et al., 2008).

Although a plausible connection between tectonic processes and changes in tayassuid diversity is not addressed here, a turnover interval observed in both the marine and continental domain during the Oligocene-Miocene transition ca. 23 Ma

(Tipple and Pagani, 2011; Lear et al., 2014; Pagani et al., 1999; Zachos et al., 2001), might have triggered these changes in ungulate diversity (Janis et al., 2000; Stromberg,

2002; 2006). In the North American fossil record, this early Miocene faunal turnover is recorded in the Runningwater Chronofauna of Webb and Opdyke (1995) and also affected bunodont and bunoselenodont ungulate taxa such as anthracotheres and entelodonts. As result, these artiodactyls became represented by a single genus during the latest Arikareean NALMA, Arretotherium and Dynohyus respectively (Janis, 1998).

Following this turnover interval, a subsequent diversification of tayassuids led to the appearance of the more progressive tayassuines (Tayassuinae) during the early

Miocene (Hemingfordian NALMA) in tropical areas of North America (MacFadden et al.,

2010) and during the middle Miocene (Barstovian) in more temperate areas of California

(Wright, 1998). These novel tayassuids have nasal cavities with an elaborate complex of bony structures that is only present in peccaries from the Miocene to recent. The floor of the nasal cavity is developed into a labyrinthine structure. Furthermore, the vomer is also pneumatic, and is developed into a pair of large, bilaterally symmetrical chambers

(Wright, 1991; Wright, 1998). In addition to the dental morphologies, detailed

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comparison of these structures suggested two main lineages that are included into a monophyletic Hesperhys-Tayassu clade encompassing a variety of early Miocene to recent American tayassuids: the Hesperhys-“Cynorca” sociale clade”, and the crown group Tayassuinae (Wright, 1998). Recent reexamination of the late Paleogene tayassuids clarified the taxonomic affinities among several of the taxa recorded in the

Great Plains and Oregon (Prothero, 2009); however, no attempts have been made to elucidate the relationships among the relatively small and more bunodont late

Oligocene-early Miocene tayassuids.

Following the taxonomic work of Wright (1998), the Hesperhys-“C”. sociale clade is characterized by medially fused pterygoid bones, pterygoid processes on the alisphenoid, vertical processes on the palatine bones, presence of a plesiochoanal chamber, a pneumatic labyrinth, a paravomeronasal element, upper molars with anteriorly displaced paraconule, and a P2 with a robust lingual cingulum or separate cusps in addition to the paracone (Wright, 1991; 1998). On the other hand, tayassuines are characterized by a maxillopalatine labyrinth having a dorsal median sulcus, upper and lower premolars with incipient (“C”. occidentale) to well-defined molarization (“P”. xiphidonticus), lack of P1/p1, and a posprotoconal groove on P4. The oldest tayassuine

(“C”. occidentale) is from early Hemingfordian assemblages in tropical areas of the

Panama Canal basin (MacFadden et al., 2010), while “C”. occidentale is not reported in subtropical areas of California until the Barstovian NALMA (Woodburne, 1969; Wright,

1998). The topology reported by Wright (1998) placed the “Hesperhys-Cynorca sociale clade” as the sister group of the Tayassuinae, mainly differing in the structure of the maxillopalatine labyrinth and the choanal fossa, but also in the degree of molarization in

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the premolars. The homology between structures in the maxilla (the atrium and the maxillopalatine labyrinth) remains open to speculation, yet Tayassuinae represents a monophyletic clade that includes at least fourteen genera (~35 species) represented in sequences ranging from the early Miocene (Hemingfordian NALMA) to the recent

(Wright, 1991; 1998). Furthermore, the way that premolars became more molariform also varies among the different tayassuid groups. It was achieved by addition of crescents in basal tayassuids like Perchoerus and the hesperhyine Floridachoerus or by addition of cusps like more progressive Neogene tayassuines (e.g, “C”. occidentale and

“Prosthennops” xiphidonticus) (Wright, 1998).

A short note about Cynorca, Cope, 1867. In his seminal work, Woodburne

(1969) recognized Cynorca Cope as a small Miocene tayassuid with type species of which is Cynorca proterva from the upper Miocene Chesapeake Group of Maryland, and transferred Thinohyus socialis Marsh to Cynorca leading to C. sociale, new combination. Prior to the systematic review of Wright (1998), Cynorca included fossils from early Late Arikareean assemblages from Oregon to late Arikareean-early

Hemingfordian ocurrences in the East Coast, and younger late early Miocene

(Barstovian) occurrences of “C”. occidentale in California (Woodburne, 1969; Wright and Eshelman, 1987). Unfortunately, similar to other ungulate groups appearing in the early Miocene (e.g. oxydactyline camels, parahippine horses), many of the relatively small bunodont tayassuids only known from partial dentitions have been consistently referred to the tayassuid genus Cynorca. Subsequent detailed comparative work confirmed that Cynorca (Cope) represented a nomen dubium and concluded that

“Cynorca” proterva is very similar to "Prosthennops" xiphidonticus (now regarded as a

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junior subjective synonym of "P." xiphidonticus), a member of the Tayassuinae (Wright and Eshelman, 1987). Moreover, the morphology of the choanal region (lacking a distinct maxillopalatine labyrinth) in “Cynorca” sociale suggested relationships to

Hesperhys placing “C”. sociale (now Marshochoerus socialis Prothero, 2015) as member of the Hesperhys -“C”. sociale clade, the sister group of other Miocene to recent tayassuines (Wright, 1991; Wright, 1998). Recent systematic work (Prothero,

2015) grouped late Arikareean specimens previously referred by Woodburne (1969) to

“Cynorca” sociale from the John Day Formation in Oregon in a new genus,

Marshochoerus Prothero, 2015. This relocation left many bunodont specimens previously referred to Cynorca without an adequate taxonomic placement, including the small Simojovelhyus from Mexico (early Arikareean).

The early Miocene Panamanian fossil record. The stratigraphic interval preserved in the Panama Canal basin (Figure 1-2) is one of the most complete and best-exposed Oligocene and Miocene volcanic sequences of the Central American arc.

While Paleogene fossil evidence of terrestrial mammalian communities in southern

North America includes scattered fossil assemblages from Mexico (Webb et al., 2003;

Ferrusquía-Villafranca, 1984; Jiménez-Hidalgo et al., 2015; Ferrusquía-Villafranca,

2006; Prothero et al., 2013), the colonization of marginal tropical areas of southern

North America (Panama Canal basin, Lat. ~9 N) did not start until the earliest Miocene

(Rincón et al., 2012; Bloch et al., 2016). In addition to their tropical location, early

Miocene terrestrial fossils from Panama are evidence of ancient ecosystems developed in a unique tectonic province: the transition zone between the Chorotega (western

Panama and Costa Rica) and Chocó (eastern Panama and Western Colombia) tectonic

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blocks (Case, 1974; Dengo, 1985; Duque-Caro, 1990). These tectonic blocks, corresponding to the early Miocene southern Central American peninsula (Figure 1-1), underwent progressive uplift from approximately 12 to 4.8 Ma leading to the disruption of pelagic marine depositional environments about 8 to 9 Ma (Coates et al., 2004). This interval roughly corresponds to mammalian overwater dispersal between South and southern North America as denoted by the earlier occurrence of sloths in North America prior to the onset of the GABI in the Pleistocene (Woodburne, 2004; Woodburne et al.,

2010).

Despite its proximity to South America (Montes et al., 2012), the majority of the early Miocene ungulates from Panama have Holarctic affinities (Whitmore and Stewart,

1965; MacFadden et al., 2006). Furthermore, ongoing taxonomic work is linking the earlier occurrences of some taxa (e.g. Paratoceras and Aguascalientia) in Panama (21-

19 Ma) to ungulates found in younger (late Miocene) and more temperate fossils assemblages from the Gulf Coast. This paleobiogeographic pattern supports a distinctive biogeographic province connecting areas of the Gulf Coast with the Panama

Canal basin during the early Miocene Hemingfordian NALMA (Rincón et al., 2012;

2015; MacFadden et al., 2010; MacFadden et al., 2014), but also during the late

Miocene (MacFadden et al., 2015). However, paleobotanical studies revealed an unusual early Miocene phytogeographic pattern in early Miocene (~19 Ma) Panamanian forests. The composition of the flora was dominated by taxa with Gondwanan (instead of Laurasian) affinities (Jaramillo et al., 2016; Bloch et al., 2016). Furthermore, the taxonomic affinities of the terrestrial mammals from the underlying Lirio Norte L. F. (~21

Ma) suggest an intriguing paleobiogeographic scenario during the earliest Miocene. In

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addition to mammalian taxa with Laurasian affinities and the remarkable occurrence of a platirrhyne monkey with clear South American affinities (Bloch et al., 2016), the fossil assemblage also includes the earlier occurrence (~2 Ma older) in North America of

Euroasian immigrant taxa such as procyonids and the sciurid Petauristodon, and also blastomerycine ruminants (Bloch et al., 2016; Rincón et al., 2013). Althoug open to speculation, this paleobiogeographic/biostratigraphic pattern suggests that some ungulates appearing in the Gulf Coast during the Hemingfordian NALMA have an earlier yet undefined biological history in tropical areas of southern North America.

In a more regional paleoecological context, the earliest Miocene was a relatively cool period preceding the warmer conditions during the Middle Miocene with distinctive high pCO2 levels but also characterized by intense volcanic activity along the western margin of North America (Kürschner et al., 2008; Graham, 2010) and the northern temperate areas of the Eastern Hemisphere (Kürschner and Kvacek, 2009).

Consequently, the conjunction of these abiotic factors might have caused biotic perturbations in mammalian communities in the temperate and subtropical areas of the

North America, ultimately favoring to the colonization of marginal tropical terrains of

Panama ca. 21 Ma.

Among the ungulate fossils from Panama, tayassuids are represented in both the late Arikareean (~21 Ma) Lirio Norte L. F. and the early Hemingfordian Centenario

Fauna (Figure 1-2). In a lithostratigraphic context, the Lirio Norte Local Fauna (L. F.) represents terrestrial mammalian communities from the uppermost part of the Las

Cascadas Formation (Figure 1-2). This interval of the Las Cascadas Formation is characterized by discrete fossiliferous sequences associated with subaerial volcanic

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products deposited in sporadic fluvial environments (Rincón et al., 2012a, 2012b, 2013,

Bloch et al., 2016). In contrast, the Centenario Fauna (MacFadden et al., 2010;

MacFadden et al., 2014) is composed of vertebrates recovered from volcaniclastic sequences from the upper part of the Culebra (early Centenario Fauna) and Cucaracha

(late Centenario Fauna) formations (Figure 1-2). Although transport is evident in many of the recovered fossils, these vertebrates inhabited a variety of sedimentary environments ranging from deltaic sequences of the upper part of the Culebra

Formation to transitional and paralic sequences from the upper part of the Cucaracha

Formation (Kirby and MacFadden, 2005; MacFadden et al., 2014; Rincón et al., 2015).

Although the colonization of volcanic terrains of the Chorotega Block occurred during the Late Arikareean, these tectonic blocks (Chorotega and Choco) corresponding to the early Neogene southern Central American peninsula underwent progressive uplift from approximately 12 to 4.8 Ma finally leading to the disruption of pelagic marine depositional environments about 8 to 9 Ma (Coates et al., 2004). This interval further corresponds to earlier stages of mammalian overwater dispersal between South and southern North America as denoted by the occurrence of sloths in North America ~ 4-6

Ma prior to the onset of the GABI in the Pleistocene (Woodburne, 2004; Woodburne et al., 2010; O’Dea et al., 2016).

The occurrence of the bunodont tayassuid Simojovelhyus in southern Mexico suggests that tayassuids inhabited low land forested areas of the Guf Coast as early as the early Arikareean (late Oligocene). Therefore, these peccaries are likely descendants of Oligocene species of Perchoerus that progressively became isolated in subtropical low land areas of the Gulf Coast during the Oligocene. By the earliest Miocene (late

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Arikareeean NALMA), intense tectonic (and volcanic) activity favored the colonization of tropical volcanic terrains (Rincón et al., 2012a; 2015) by ungulates with a more temperate ancestry including bunodont tayassuids similar to Marshochoerus

(MacFadden, et al., 2010; MacFadden et al., 2014; Rincón et al., 2015; Bloch et al.,

2016). A diversification phase inferred for other herbivore immigrant groups like floridatraguline camels and protocertine protoceratids (Rincón et al., 2012; Rincón et al.,

2015) might be closely related to changes in the habitat structure (from more open to close habitats). Consequently, the composition of the forest, representing a new niche for ungulates, played an important role in this diversification. Similar morphological change is expected in other ungulate groups as they inhabited a tropical marginal habitat with food resources not present in temperate areas of North America during the early Miocene (21 to 19 Ma). Despite that the early Miocene fossil terrestrial record is sparse south of Mexico, the biostratigraphic pattern observed in bunodont tayassuids suggests that these forms, similar to other ungulates with similar paleobiogeographic distribution (e.g. the protoceratine Paratoceras), likely diversified in tropical areas during the earliest Miocene prior to being recorded in younger sequences in the Gulf Coast during the Hemingfordian NALMA (Rincón et al., 2015). Herein, I describe recently recovered partial tayassuid partial dentitions collected from the early Miocene (~21 to 19

Ma) volcanic and volcaniclastic sequences from the Panama Canal area (Gaillard Cut).

The new fossils include partial tayassuid dentitions from three different stratigraphic levels: the upper part of the Las Cascadas Formation (the late Arikareean Lirio Norte L.

F.), the upper part of the Culebra Formation (early Centenario Fauna, earliest

Hemingfordian), and the upper part of a transitional sequence correlated to the upper

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part of the Cucaracha Formation (late Centenario Fauna, earliest Hemingfordian) in the southern part of the Gaillard Cut. I also examine the structure of the maxillopallatine labyrinth (using CT tomography) and the morphology of the dentition preserved in specimens referred to “C”. occidentale from the early Hemingfordian Centenario Fauna

(MacFadden et al., 2010) in Panama. In addition to justifying and discussing my taxonomic allocations, I also consider and discuss the resulting paleobiogeographic and phylogenetic hypotheses regarding the origins of early Miocene bunodont tayassuids.

Systematic Paleontology

Class MAMMALIA Linnaeus, 1758

Order ARTIODACTYLA Owen, 1848

Family TAYASSUIDAE Palmer, 1897

Subfamily Hesperhyinae Prothero, 2015

Hesperhyinae, gen. et. sp. nov.

“Cynorca” (in part), MacFadden et al., 2010

Type species. Hesperhyinae, gen. A et. sp. nov. B. from the early

Hemingfordian Centenario Fauna in Panama.

Included species. Hesperhyinae n. gen. A & sp. A. from the late Arikareean Lirio

Norte Local Fauna in Panama.

Diagnosis. Differs from all members of the Hysperhys-M. socialis clade in having wider and arcuate anterior border of pleasiochoanal fossa on palate, lower p4 lacking paraconid, depth of the mandible below m1 shorter than the m1-m2APL, and P3 with posteriorly placed lingual cingulum. Further differs from Hesperhys, Wrightohyus,

Floridachoerus, Stuckyhyus, Fremdohyus, and Lucashyus in having an unfused symphysis and smaller size. Further differs from Hesperhys, Floridachoerus and

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Lucashyus in lacking a continuos cingulum on P4. Further differs from Marshochoerus in having more reduced upper premolars, m2 relatively larger than m1 and m3, and p4 lacking paraconid. Further differs from “Cynorca” occidentale in lacking a multicuspid talonid on p3, and a p4 with differentiated protoconid and metaconid. Further differs from Hesperhyinae, gen B. et. sp. nov A in having a less elongate m3 hypoconulid lobe, less square p4, and lacking a transversely expanded talonid on p3. Further differs from

Dyseohyus in having transversely narrow upper molars.

Comments. The diagnosis of this new hesperhyine genus combines morphologies observed in similarly sized early Miocene (Late Arikareean to early Hemingfordian) tayassuids from Panama. It combines the morphology of the lower dentition observed in fossils recovered from the upper part of the Las Cascadas Formation in the Lirio Norte area ca. 21 Ma (Hesperhyinae, gen A. et. sp. nov A) with cranial and upper dentitios preserved in hesperhyine tayassuid fossils recovered from the upper part of the Culebra

Formation c.a. 19 Ma (Hesperhyinae, gen A. et. sp. nov B). Although similar in many aspects of the dental morphology, I consider the fossils herein described exhibit enough morphological differences to warrant the designation of two new different species (see below).

Hesperhyinae n. gen. A & sp. A.

Figure 4.2, Table 1-1

Holotype. UF 280424, left mandible with p3-m3.

Referred specimens. UF 267027, left DP3; UF 265270, right DP4; UF 280051, left DP4 (partial); UF 281140, left M2 (partial); UF 281149, left M2 (partial); UF 244219, right p4; UF 246834, left m2; UF 267038, right m2; UF 280726, right m3.

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Distribution. Only known from early Miocene (Late Arikareean) sequences from the Panama Canal basin.

Locality and horizon. Lirio Norte L. F. (site YPA024 in UF Vertebrate

Paleontology Collection), Panama Canal area, Panama, Central America. The type specimen (collected by S. Ascari) and referred material were found in the upper part of the Las Cascadas Formation (Figure 1-2), equivalent to the late Arikareean Ar4 faunal zone (22.8-19.05 Ma) North American Land Mammal Age (NALMA) at higher latitudes and precisely dated to 20.93 +/- 0.17 Ma (Rincón et al., 2015, Bloch et al., 2016).

Diagnosis. Bunodont hesperhyine tayassuid that differs from similarly sized

Hesperhyinae n. gen. A & sp. A in having less distinct conulids on lower molars, more reduced hypoconulid lobe on m3, and less distinct posterolabial process of the metaconid on lower molars.

Description

Upper deciduos dentition. The DP3 (UF 267027) is tri-cusped, tri-rooted, and anteriorly wedge-shaped (APL: 8.85 mm; 6.78 mm) in occlusal outline (Figure 4-2A,

Table 4-1). The enamel is thick and has basal crenulations on both labial and lingual sides of the crown. The paracone is located anteriorly on the apex of the triangle and bears a distinct wear facet on the anterior end at the base of the crown. The posterior cusps, metaconule and metacone, make up the talon and are subequal in height but distinctively lower than the anterior cusp (paracone). The metaconule bears small anterior and posterior labial processes while the metacone has a posterior ridge connecting it with the posterior cingulum. The cingulum is incomplete and restricted to the posterolingual segment of the crown. Enamel crenulations occur along the basal

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part of the crown, but are mostly concentrated to the lingual and labial sides of the paracone, and the labial segment of the metacone.

The crown of the DP4 (UF 275279) is nearly square and completely molariform

(APL: 10.51 mm; TW: 9.97 mm). It has four main cusps located at the protocone, hypocone, paracone, and metacone positions (Figure 4-2B). Three distinct conules are aligned longitudinally in the midline of the crown. The paraconule is located anterior and near the anterior cingulum, the metaconule is blocking the transverse valley, and the hypocone is located posteriorly on the cingulum but slightly more lingually placed than the metaconule. The crown of DP4 is anteroposteriorly asymmetric, with a distinctive labial side that is longer than the lingual side. While the anterior and posterior cingula are distinct, the labial cingulum is faint and represented by a group of small but distinct crenulations on the enamel. The cingulum fades on the sides of the lingual cusps.

Upper permanent dentition. The crown of M2 is partially preserved in UF 281140

(Figure 4-2 C). Although missing the hypocone and the posterior part of the crown, the crown is square (APL: ~11.3 mm and TW: ~12.0 mm) and has distinct anterior cusps

(protocone and paracone), the paracone is more forwardly placed and separated from the protocone by a paraconule that is located at the antero labial margin of the protocone. The metaconule is distinct and located at the anterolingual segment of the metacone blocking the longitudinal valley. A distinct ridge connects the metaconule with the metaconule. The anterior cingulum is restricted to the anterior part of the protocone but it is interrupted by a distinctive paraconule while the labial cingulum is low and connects the base of the metacone to the paracone.

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Lower dentition. The p3 (UF 280424; Figure 4-2D-F) is double-rooted and its crown is oval in occlusal view (APL: 9.90 mm; TW: 5.60 mm; p3APL/TW: 1.76) with a large, conical and undivided main cuspid (protoconid) forwardly located on the mid-line in occlusal view. An anterior ridge connects the apex of the protoconid with a low anterior cuspulid placed in the position of the paraconid. A distinct posterior ridge connects the apex of the protoconid with a small posterior cuspulid on the posterior cingulid forming two small basins in both, the labial and lingual sides of the talonid.

The p4 (UF 280424; Figure 4-2D-F) is two-rooted. The crown is oval (10.4 mm

APL; 7.1 mm TW; APL/TW ratio: 1.46) and larger than that of p3. It has a distinct talonid notch and a barely discernible paraconid (Figure 4-2). The talonid represents about

34% of the total length of the crown and its height is about 50% of that of the trigonid.

The main cuspid has a faint and shallow longitudinal groove with no clear separation between labial and lingual cuspids. This groove disappears anteriorly after reaching a faint and low anterior cingulid on the position of the paraconid that connects anteriorly to a continuous tranverse valley. A distinct cristid (posterolabial process of the metaconid) extends posterior to the apex of the metaconid and disappears at the transverse valley.

The talonid is exclusively formed by a main posterior cuspid (hypoconulid) flanked by two faint processes in the position of the hypoconid and entoconid.

The lower m1 (UF 280424; Figure 4-2D-F) is anteroposteriorly elongate (Table 4-

1) and relatively larger than the p4. It has four main distinct, low, and rounded

(bunodont) cuspids. The trigonid is taller than the talonid (Figure 4-2E) and separated from it by a distinct transverse valley. The trigonid and talonid are similar in relative length but the lingual cuspids (metaconid and entoconid) are larger than their labial

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counterparts (protoconid and hypoconid) and this morphology is also evident in m2 and m3. As for other early Miocene tayassuids, the lingual cuspids (metaconid and entoconid) are located slightly more anteriorly than the protoconid and hypoconid

(Figure 4-2D). The barely distinct cristid obliqua extends anteromesially towards the metaconid but is interrupted by the transverse valley and by the distinct posterior process of the metaconid. There is no evidence of any grooves in the posterolabially aspect of the metaconid. The talonid is formed by two posterior cuspids (hypoconid and metaconid) flanking two relatively small cuspulids, the entoconulid anteriorly and the hypoconulid posteriorly. The entoconulid is blocking the transverse valley as it meets a faint posterolabial process of the metaconid. The hypoconulid is similar in size to the entoconulid and is also located in the midline of the crown. The hypoconulid is located on the posterior part of a distinct posterior cingulid and is surrounded posteriorly by small cuspids labially and lingually restricted to posterior part of the crown. A faint ectostylid is present at the lingual opening of the transverse valley.

The occlusal area of the crown of m2 is the largest of the cheektooth series. The crown is anteroposteriorly elongate (13.21 mm APL; 10.69 mm TW), and has four principal cusps (UF 280424; Figure 4-2D-F). The protoconid is higher than the metaconid and both cuspids create a transversely wider anterior segment. A distinct cristid descends lingually from the protoconid reaching the anterior surface of the metaconid at the same height of the talonid. The hypoconid and entoconid are subequal in size and are separated from the anterior pair of cusps by a wide transverse valley.

The entoconulid is distinct and blocks the transverse valley as it approaches to the anterolingually surface of the hypoconid. Similar to m1, a barely distinct cristid obliqua

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meets a distinct posterior process of the metaconid at the transverse valley. The hypoconulid is located at the posteriormost part of a distinct posterior cingulid and similar to m1, it is flanked posterolabially and posterolingually by small cuspids also restricted to posterior part of the crown. A small but distinct ectostylid is located at the labial opening of the transverse valley.

The m3 APL is trilobed (14.70 mm APL; 8.99 mm TW) (UF 280424; Figure 4-2D-

F). The anterior part of the crown resembles that of the m2 while a distinct hypoconulid is centrally located in the posterior part and is flanked posteriorly by five small cuspulids

(Figure 4-2D). Three of these are located posterior to the hypoconulid, whereas the remaining two are located at the labial and lingual sides of the hypoconulid, respectively

(Figure 4-2F). A faint ectostylid is blocking the labial aperture of the transverse valley.

The APL measured between the posterior end of the transverse valley to the posterior end of the hypoconulid lobe represents about 55% of the total anteroposterior length of the crown while the m3APL/TW ratio is 1.64.

Mandible. The horizontal ramus is partially preserved on UF 280424 (Figure 4-2D-

F). The APL measured between the posterior alveolus of p2 to the posterior end of the m3 is 59.6 mm. The symphysis is not fused and the depth of the mandible below the m1 is subequal to the combined anteroposterior length (APL) of the m1-m2 series. Along the cheek teeth, the widest point of the mandible is located below the roots of m2. In lateral view, the depth of the mandible is uniform for most of its length, only increasing drastically posterior to the anterior roots of the m2. The posterior end of the symphysis is located below the anterior alveolus of the p2. Two foramina are located on the labial surface of the mandible; the mental foramen is located below the anterior root of p3

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while the posterior foramen is located below the posterior root of p4. The digastric fossa is shallow and distinct but it is not connected to the foramen (~ genial spine) located just above the posteroventral end of the unfused symphysis (Figure 4-2).

Comparisons

The M2 of Hesperhyinae n. gen. A & sp. A has a distinct metaconule located slightly anterior to the metacone and hypocone, similar to the type of Marschochoerus socialis (YPM 11874) from the John Day Formation and other late Arikareaan herpehyines (Hesperhys, Floridachoerus, and Thinohyus). This shared character is considered diagnostic of the Hesperhys -“Cynorca” sociale clade (Wright, 1998).

However, it differs from other hesperhyines like Lucashyus, Stuckyhyus and

Floridachoerus in having a more bunodont lower molars with very reduced cristid oblique and longitudinal valleys blocked by distinct entoconulids, unfused symphysis, and having a p4 lacking the paraconid. While having upper dentitions with similar dimensions, Hesperhyinae n. gen. A & sp. A differs from late Arikareean and early

Hemingfordian Wrightohyus in having a less reduced m3 hypoconulid (Prothero, 2015).

Furthermore, comparison to M. socialis (AMNH 7393 and UCMP 66861) from the John

Day Formation (Oregon) (Woodburne, 1969) shows that Hesperhyinae n. gen. A & sp.

A similarly has an m2 that is slightly wider than m1 and m3, a p3 with incipient anterior basal cuspid, undivided main cuspid, and a poorly developed talonid, a p4 with a moderately broad anterior end, a faint and low paraconid, a narrow postdigastric sulcus, and a relatively short mandible with the posterior edge of symphysis located below the anterior root of p3. Hesperhyinae n. gen. A & sp. A differs from late Arikareean

Marshochoerus socialis in lacking a paraconid on p4, having larger molars and premolars (Figure 4-3), more reduced M3/m3, a squarer crown on p4, and a relatively

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shallower mandible below m1 (Table 4-2). In this aspect, the Lirio Norte tayassuid is more similar to the AMC 2894, a referred specimen of “C”. sociale from the early

Hemingfordian Garvin Gully Fauna in Texas.

Hesperhyinae n. gen. A & sp. A has a squarer p4 with a posterolabial process of the metaconid that is relatively smaller than that of “Cynorca” occidentale (F:AM 73660, type). The p4APL/TW is 1.46 for Hesperhyinae n. gen. A & sp. A while is 1.75 for “C”. occidentale). Furthermore, the p4 of Hesperhyinae n. gen. A & sp. A lacks a bicusped talonid, the M3/m3 are less reduced; and the mandible is relatively shallow (Table 4-2) with an unfused symphysis. It differs from the tayassuine “Prosthennops” xiphidonticus

(= C. proterva of Woodburne, 1969) in having a DP3 lacking a crescentic protocone.

The p4 has similar proportions to those of “P”. xiphidonticus (APL/TW ratio: ~1.5 for

USNM 20518) but lacks the undifferentiated protoconid and metaconid and multicuspid talonid. The m3 is more reduced in Hesperhyinae n. gen. A & sp. A. Hesperhyinae n. gen. A & sp. A differs from Dyseohyus in having a p3 lacking the twinned metaconid and protoconid.

Hesperhyinae n. gen. A & sp. A differs from Hesperhyinae n. gen. B & sp. A from the late Centenario Fauna in having an unfused symphysis, a p2 that is more anteriorly located (above the posterior end of the symphysis), a p3 with no additional anterior cingulid; a less square p4 (p4APL/TW is ~1.58 for Hesperhyinae n. gen. B & sp. A) with un-differentiated protoconid and metaconid, and lacking paraconid; a more reduced hypoconulid lobe on m3, a shallower postdigastric sulcus, a shallower mandible with a depth less than the combined length of the m1-m2 APL, the lack of distinct metaconulids on lower molars, a less developed digastric fossa that is not connected

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with the foramen in the lower posterior part of the symphysis; lacking a genial spine at the ventral margin symphysis.

Hesperhyinae n. gen. A & sp. A differs from the Pope’s Creek Tayassuid Sp. A of

Wright and Eshelman (1987) in lacking the steep-sided protoconids on lower p2 and p3; however, Hesperhyinae n. gen. A & sp. A from Panama differs from Simojovelhyus in being relatively larger, having more inflated crowns, a m2 relatively wider than m1 and m3, more distinct entoconulids on lower molars, having a transverse valley partially blocked by the posterolabial process of the metaconid, having a more reduced hypoconulid on m3, and a m3 hypoconulid that is in contact with the ento/hypoconid.

Hesperhyinae n. gen. A & sp. A from the late Arikareean Lirio Norte L. F. differs from Hesperhyinae n. gen. A & sp. B from the early Centenario Fauna (“C”. occidentale of MacFadden et al., 2010) in having relatively smaller molars, having an m1 lacking a distinct posterolabial process of the metaconid, having m2 and m3 with less distinct posterolabial process of the metaconid; and a relatively less reduced hypoconulid lobe

(Table 4-2). Taking into account that the diagnosis of the new species Hesperhyinae n. gen. A & sp. A is based on the lack of a paraconid on p4, a tayassuine morphology not present in hesperhyines (Wright, 1998), the diagnosis of this new species is further supported by cranial and dental morphologies preserved in more complete fossils, that although similar in many morphological aspects, are here referred to a second new species, Hesperhyinae n. gen. A & sp. B previously recovered from the upper part of the overlying Culebra Formation in the Guillard Cut are (see below).

Hesperhyinae n. gen. A & sp. B

Figure 4-4, 4-5; Table 4-3

= “Cynorca” occidentale MacFadden et al., (2010:292)

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Diagnosis. Hysperhyine tayassuid that differs from Hesperhyinae n. gen. A & sp.

A in having lower molars with stronger entoconulids, more distinct posterolabial cingulids, and m3 with less reduced hypoconulid lobe on m3.

Holotype. UF 234400, partial rostrum with right and left P1-M3 from the early

Centenario Fauna (Culebra Formation).

Paratype. UF 237885, partial mandible with left m1-m2 from the early Centenario

Fauna (Culebra Formation).

Referred material. UF 237884, partial left mandible with m1; UF 281475, left lower m3.

Locality and horizon. Lirio Norte area (site YPA016 in UF Vertebrate

Paleontology Collection), Panama Canal area, Panama, Central America. The type specimen was collected by AFR in the upper part of the Culebra Formation (Figure 1-2), equivalent to the earliest Hemingfordian He1 faunal zone (MacFadden et al., 2010;

MacFadden et al., 2014).

Description

Skull. The partially preserved rostrum (UF 234400) lacks any evidence of sutures; however, it preserves the nasal area anterior to P4, maxillae, palatines, a partially preserved plesiochoanal fossa, and the nasal cavity (Figure 4-4 A-D). The distance between the maxillary tuberosity and the canine buttress is ~ 81.2 mm and ~22.0 mm between the posterior wall of the canine buttress and the anterior root of P2. The maxillary tuberosity is located > 5.0 mm posterior to the M3. The rostrum is anteriorly attenuated with nasals arising ventrally above the P4 about 66% of the P2-M3 APL

(Figure 4-4A,C) and forming a distinctive low angle (~30°) with the occlusal plane.

There are two parasaggital suparaorbital canals running parallel on the dorsal part of

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the nasals (Figure 4-4A,C). The canine buttress is distinct and has a flat anterior expression while the orbital fossa seems restricted to the dorsal part of the M1. The infraorbital foramen is located dorsal to the anterior root of the P4 (Figure 4-4A).

Images generated from microCT scan data reveals that, although not completely preserved, a transversely symmetric maxillopalatine labyrinth extends from the dorsal part of the P1 to the posterior part of the P3 (Figure 4-4E). The floor of the maxillopalatine labyrinth (subatrial chamber) is bilaterally symmetrical and composed by two sulci tapering anteriorly (Figure 4-4H). These sulci run from the ethmoid cavity, to the openings located mesial to the anterior root of the M1 on the palate (Figure 4-4G).

Each sulcus defines an anteroposterior chamber connecting a narrow passage posteriorly to a wide space on the palate, the plesiochoanal fossa (Figure 4-4B).

Posterior to the maxillopalatine labyrinth, the walls of the palatines are appressed medially isolating the ventral part of a choanal fossa at the level of the M3 (Figure 4-4).

Despite breakage, the anterior part of the floor of the pleasiochoanal fossa is depressed along the midline forming a narrow but distinct median sulcus (Figure 4-4). This sulcus seems coterminal with the dorsal part of the tectum of the maxillopalatine labyrinth.

There is no evidence of an atrium in the maxillopalatine labyrinth; however, a small splint of bone, symmetrically located on the lateral sides of this empty space resembles the supraatrial lamina. Although not complete, this lamina extends anteriorly from behind the P4, medial to the maxillary canal and dorsal to the palatine canal, to the dorsal part of the paravomeronasal chamber, just above the P1-P2 diastema. The paravomeronasal chamber occupies the majority of the nasal area anterior to the P3.

Furthermore, a shell like bony element lacking septa, the anterior protuberance of the

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maxillopalatine labyrinth, is located in both sides of the maxillae above the P2s. The paravomeronasal element is preserved lying lateral to the paraseptal cartilage (Figure

4-4F).

The diastema posterior to the P1 is equal to the length of the P2. The diastematal crest is weak and is located adjacent to the anterior part of a ventral pocket confined between the crest and limited dorsally by the alveolus for the canine. The distematal crest posterior to P1 makes up the medial border of an elongate groove with a ventral, rather than lateral, primary orientation. Palatine foramina occur in the palate medial to the lingual roots of the P4. The bony palate extends posterior to M3 while a wide and arcuate anterior margin of a relatively wider plesiochoanal fossa lies medial to the anterior roots of M3. The cheek tooth arcade is slightly curved (Figure 4-5).

Upper dentition. The DP1 is small (Figure 4-5; Table 4-3), anteroposteriorly elongate (4.7 mm APL; 2.6 mm TW), double rooted, and separated from the P2 by a 5.5 mm diastema. The protocone is more anteriorly located, while the posterior of the crown has a distinct a basal cuspule.

The P2 and P3 (Figure 4-5) are oval ((9.45 mm APL; 5.88 TW); (11.12 mm APL;

7.5 mm TW)). The paracone is flanked posteriorly by a low but distinct cingulum while the anterolingual part of the base of crown is fashioned by faint crenulations in the position of the anterior cingula. A distinct crista connects the apex of paracone with the posterolingual side of the P2 and P3. The crowns are heavely worn yet the enamel in the talon is crenulated and lacks any distinct cuspules. The posterior cingula are restricted to the posterior part of the crowns with no evidence of cingula in the labial part of the paracone.

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The crown of P4 is subtriangular (8.76 mm APL; 10.12 mm TW) and submolariform. Wear patterns in the enamel suggest that the crown has a larger cusp

(metacone) anteriorly bordered by a smaller twinned cusp (parametaconule sensu

Woodburne, 1969) and both constitute the labial half of the crown. In the lingual half, grooves and shallow pits on the enamel suggest the presence of discontinuous anterior cingulum, a more continuous posterior cingulum, and a posteriorly elongate protocone; unfortunately, the presence of a metaconule cannot be directly confirmed. The cingulum is absent lingually and moderately well developed labially. The M1 and M2 are square and consist of four principal cusps. The M1 is heavely worn but the presence of paraconule, metaconule and hypoconule can be inferred in less worn specimens. The

M2 is larger than the M1 (M1APL: 10.73 mm; M1TW: 11.54 mm and M2APL: 11.74 mm;

M2TW: 12.9 mm). The cingula are weak labially, absent lingually and relatively well developed on the anterior and posterior segment of the M1 and M2 (Figure 4-5). The labial cusps are anteriorly projected along the molars resulting in a relatively rhomboidal outline clearly noticeable on the M3 due to extreme reduction of the posterior segment

(M3 APL: 9.67 mm; M3TW: 10.58 mm). The basal lingual aspect of the crowns in the upper molars is moderately expanded (acuminate). The posterior half of the M3 is reduced and has a distinct metacone, metaconule, and hypocone with a hypoconule located posteriorly to the hypocone and surrounded anteriorly by small cuspules. The cingulum in M3 is weak labially, strong on the anterior and posterior margins, and absent on the lingual side of the crown.

Mandible. Two horizontal rami (Figure 4-6 A-F) from the early centenario Fauna

(Upper Culebra Fm) are available for description; UF 237885 (paratype) representing an

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adult individual with the m1 (10.48 mm APL; 7.70 mm TW) and m2 (12.2 mm APL; 9.32 mm TW) fully erupted (Figure 4-6 A-C) and UF 237884 representing a juvenile with the permanent m1 (11.6 mm APL; 8.51 mm TW) in early wear stages (Figure 4-6 D-F). In both mandibles, the depth of the ramus is homogenous below the p3-m2 series and is shorter than the combined anteroposterior length (APL) of the m1-m2 series below the p4. In occlusal view, the widest point of the mandible is located at the level of the m2

(Figure 4-6 A, D). The posterior alveolus of the p2 is located above the posteroventral end of an unfused symphysis. Two foramina are located in the labial surface of the mandible; the anterior one is located below the anterior rooth of the p3 and the posterior is located below the posterior root of the p4. A small foramen is also located posterior to the ventral margin of an oval unfused symphysis near the ventral margin of the mandible.

Lower dentition. The lower m1 is anteroposteriorly elongate (APL= 10.48 mm and TW= 7.70 mm; m1APL/TW: 1:36) and has four main distinct low and rounded

(bunodont) cuspids. The trigonid is distinctively taller than the talonid (Figure 4-6 D-F) and separated from the talonid by a distinct notch. The protoconid is stronger than the metaconid, whereas the entoconid and hypoconid are about the same size. In occlusal view, the external cuspids (metaconid and entoconid) of the m1 are slightly more forwardly located than the protoconid and hypoconid (Figure 4-6 D-F). A distinct cristid connects the anterior surface of the metaconid with the protoconid. The anterior part of the trigonid includes a cristid of the protoconid that runs lingually and reaches the anterior part of the metaconid at the same height of the talonid. Although smaller and less developed than the anterolingual crest of the hypoconid, the posterior cristid of the

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metaconid runs posterolingually on the lower molars. The labial aspect of the anterior part of the m1 is dominated by a small cingular segment restricted to the anterolabial part of the crown but roughly located at the same height that the talonid notch. The talonid includes two bunodont cuspids (hypoconid and entoconid), an intermediate but distinct entoconulid, and the hypoconulid. The hypoconulid is located on the posterior cingulum is also preserved. A small ectostylid is blocking the lingual opening of the transverse valley (Figure 4-6 D-F).

Similar to m1, the crown of m2 is anteroposteriorly elongate with four principal cusps but proportionally larger (Table 4-3). The protoconid has a more conical appearance than the larger metaconid and both cuspids make a transversely wider anterior segment. A distinct cristid descends lingually from the protoconid, reaching the anterior surface of the metaconid at the same height of the talonid. The hypoconid and entoconid are subequal in size and are separated from the anterior pair of cusps by a wide transverse valley. The entoconulid is strong and located in the anterolingually surface of the hypoconid partially blocking the transverse valley. The hypoconulid is distinct and has distinct cingulids on the posterior surface of the hypoconid and entoconid. A small anterolabial cingulid is present in the surface of the protoconid at the same level of the cingulids surrounding the hypoconulid in the posterior part of the crown. A small ectostylid is located at the labial opening of the transverse valley.

The crown of the m3 (UF 281475) is elongate posteriorly (Table 4-3) and characterized by a hypoconulid surrounded by a multicuspid lobe bearing five small cuspulids. Three of them are restricted to the posterior end of the hypoconulid, whereas the remaining two are located at the labial and lingual sides of the hypoconulid (Figure

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4-6 G-I). The APL of the hypoconulid represent about the 33% of the total anteroposterior length of the crown (Table 4-2). A faint ectostylid is blocking the labial opening of the transverse valley.

Comparisons

UF 234400 is a member of the Hesperhys – “Cynorca” sociale clade based on having a pneumatic maxillopalatine labyrinth, presence of a paravomeronasal element lying lateral to the paraseptal cartilage, and P2 having a robust cingulum in addition to the paracone (Wright, 1998). The morphology of the maxillopalatine labyrithm is most similar to that of the Jay-Hem specimen (AMNH 73666) reported by Wright (1991). The pleasiochoanal fossa has a distinct median sulcus that is coterminal with the dorsal part of the tectum of the maxillopalatine labyrinth. Although not clearly preserved, the small splint evidencing the supraatrial laminae, a morphology not present in Marshochoerus socialis (Wright, 1998), suggests that Hesperhyinae n. gen. A & sp. B has a compartimentalized maxillopallatine labyrinth with a median sulcus extending more posteriorly than that present in the early Hemingfordian Jay-Hem specimen (Wright,

1991).

Similar to the late Arikareean Marshochoerus socialis from Oregon (UCMP

66862), the cheektooth arcade is slightly curved, the diastematal crest between the anterior upper premolars is weak and adjacent to the anterior part of a ventral pocket confined between the crest and limited dorsally by the alveolus for the canine. However, this depression is deeper in Hesperhyinae n. gen. A & sp. B.

Similar to Barstovian “Cynorca” occidentale, the bony palate extends posterior to

M3 while a wide and arcuate anterior margin of a relatively wider plesiochoanal fossa lies medial to the anterior roots of M3. However, Hesperhyinae n. gen. A & sp. B has a

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relatively shallower mandible below m1 than “C”. occidentale. The depth of the mandible below the m1 is subequal to the combined length of the m1-m2 series in UF

237885 and UF 237884 (Figure 4-6 A-F) whereas in the holotype of “C”. occidentale it is

25% larger than the m1-m2 APL. Hesperhyinae n. gen. A & sp. B has a relatively shorter C1-P2 diastema.

The attenuation of the rostrum in Hesperhyinae n. gen. A & sp. B is more intense than in any early Miocene tayassuid known from skulls The nasals arise dorsally above the P4 about 66% of the P2-M3 APL in Hesperhyinae n. gen. A & sp. B, while in extant

Tayassu tajacu (UF M 177228) they arise above the P4 for about ~120% of the P2-M3

APL, and aproximately 80 % in Dyseohyus fricki (LACM (CIT) 2039) and Dyesohyous siouxensis (Table 4-2), and a relatively shorter and more attenuated rostrum than that of

“C”. occidentale.

Although has comparable P2-M3 APL dimensions to those observed in “C”. occidentale (AMNH 73660), Hesperhyinae n. gen. A & sp. B is approximately 10% larger than M. socialis and approximately 18% smaller than Barstovian Dyseohyus stirtoni (FAM 73679) from Colorado (Table 4-2). The lower dentition of Hesperhyinae n. gen. A & sp. B is similar in dimensions to that of Hesperhyinae n. gen. A & sp. A from the Lirio Norte Local Fauna; however, the anterolabial cingulids are stronger in

Hesperhyinae n. gen. A & sp. B as well as the reduction of the hypoconulid lobe is more intense.

There is no evidence of the DP1 in the type for “Cynorca” occidentale and in

Barstovian D. stirtoni, yet it is present in Marshochoerus socialis and Hesperhyinae n. gen. A & sp. B. The posterior position of the cingula on upper P2-P3 is more similar to

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that observed in the type of M. socialis. In Hesperhyinae n. gen. A & sp. B, the cingula are restricted to the posterolingual part of the crowns connecting the labial and lingual sides of the posterior part of the talons; in contrast, cingula run posterolabially in “C”. occidentale, connecting the labial and posterior margins of the crowns. Furthermore,

Hesperhyinae n. gen. A & sp. B has relatively more elongate P2-P3 than “C”. occidentale, P. xiphidonticus, D. stirtoni, and extant Tayassu tajacu with a reduction that is only comparable with that observed in the late Arikareean Pope’s Creek species

(USNM 336459, Table 4-2). There is no evidence of the distinctive cuspules of “C”. occidentale on the P3 talon of Hesperhyinae n. gen. A & sp. B; instead, heavy crenulated enamel is preserved despite intense wear.

There is no postprotoconal groove in the heavily worn P4 in UF 234400; however, the pits preserved in the occlusal surface and the longitudinal elongation of the protocone suggest that there was a longitudinal groove connecting the labial side of the protocone with the posterior cingulum (Figure 4-5). This groove is clearly preserved in the type of Marshochoerus socialis but extends differently in the type of “C”. occidentale

(Barstovian) where the postprotoconal groove never reaches the posterior cingulum and opens lingually. Hesperhyinae n. gen. A & sp. B has a more reduced M3 than M. socialis, “P”. xiphidonticus, D. stirtoni and extant Tayassu (Table 4-2).

Hesperhyinae n. gen. A & sp. B has a relatively more elongate hypoconulid lobes on the m3 than any other early Miocene bunodont tropical tayassuid except the Pope’s

Creek species and Hesperhyinae n. gen. B & sp. A from the late Centenario Fauna. The m3APL/APLhyd ratio is ~1.6 for Hesperhyinae n. gen. A & sp. B while the elongation is extreme in the Pope Creek’s tayassuid (USNM 205988) with a ratio of 1.8. Additional

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values calculated for other early Miocene tayassuid are consistently lower than 1.4

(Table 4-2). The digastric fossa of Hesperhyinae n. gen. A & sp. B is relatively shallower than that of Hesperhyinae n. gen. B & sp. A from the late Centenario Fauna but similar in morphology to that of Hesperhyinae n. gen. A & sp. A from the Lirio Norte L. F.

Hesperhyinae n. gen. A & sp. B differs from Stuckyhyus siouxensis from the latest

Arikareean from Nebraska in having a relatively small maxillary tuberosity; a posterior end of a wider and more arquate plesiochoanal fossa ending medial to M3; and having a postdental process of palate extending posterior to M3. Similar to S. siouxensis and tayassuines (e.g. “Prosthennops” and Dyseohyus), the cranial sutures are indistinguishable in Hesperhyinae n. gen. A & sp. B. The distinctively wide plesiochoanal fossa with a more arcuate anterior margin on the palate and the relative more elongate P2-P3 series are unique morphologies not present in other early

Miocene hesperhyines, therefore justifying a generic distinction between

Marshochoerus and Hesperhyinae, gen. A. Given the fact that the morphologies for the skull and upper dentition for Hesperhyinae n. gen. A & sp. A are not known, and that

Hesperhyinae n. gen. A & sp. B is mainly represented by a partial skull with teeth in advanced wear stages, it seems more suitable to define a new genus (Hesperhyinae n. gen. A & sp. A) that, although retaining plesiomorphic morphologies (e.g. p4 lacking a multicuspid talonid and a differentiated protoconid and metaconid), exhibits more bunodont crowns on lower molars with distinct conulids blocking the longitudinal valley.

Finally, the tayassuid fossils here referred to Hesperhyinae n. gen. A & sp. A from the early Centenario Fauna (Upper Culebra Formation) are almost morphologically indistinguishable from the isolated partial dentitions reported as “Cynorca” sociale from

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the early Hemingfordian Pollack Fauna in Delaware (Emry and Eshelman, 1998).

Although only represented by isolated teeth with dimensions that have never been reported, some morphological resemblances are clear including: 1) similar proportions on the crown of upper molars based on the illustrations; 2) the development and position of the posterior cingula on P2 and P3: 3) the relative reduction of the hypoconulid lobe on lower m3; and 4) a P4 with a posterior protoconal groove in the occlusal surface that does not reach the lingual side of the crown (Emry and Eshelman,

1998:fig. 5). Among these morphologies, it is necessary to cite the remarkable similarity between the upper P4 from the Pollack Farm and the P4 of “C”. occidentale previously noted: “ …It [the P4] differs [from the P4 of C. proterva ( = “P”. xiphidonticus),

Tayassuids species A of Wright and Enshelman (1987), and C. sociale ( = M. socialis)] in having more definite separation of the paracone and metacone, and in this respect appears to be more nearly comparable to the P4 of “C”. occidentale”. (Emry and

Enshelman, 1998:166).

Floridachoerus White, 1941

Desmathyus Olsen, 1962

Desmathyus MacFadden and Webb, 1982

Floridachoerus Albright, 1999

Floridachoerus Wright, 1991

Hesperhyus McKenna and Bell, 1997

Floridachoerus Wright, 1998

Floridachoerus Prothero, 2015

Type and only species. Floridachoerus olseni White, 1941

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Diagnosis. A hesperhyine having a P3 with a large lingual crescent in the protocone position, retaining the broad pterygoid processes of the alisphenoid that join the palate at a high angle (Prothero, 2015).

Distribution. Early Hemingfordian, Thomas Farm Local Fauna, Gilchrist County,

Florida (White, 1947); Floridachoerus sp. from the early Late Arikareean, Toledo Bend

Local Fauna, Newton County, Texas (Albright, 1999); and aff. Floridachoerus sp. from the early Hemingfordian Centenario Fauna in Panama.

Floridachoerus sp.

Figure 4-6

aff. Floridachoerus sp.

Figure 4-7, Appendix H

Referred material. UF 236034, right M1 or M2; UF 271646, partial right M1 or M2.

Locality and horizon. Fossils were collected in two different localities now grouped in the Centenario Fauna. UF 236034 was collected in the lower conglomerates of the Cucaracha Formation (Early Centenario fauna YPA016) in the Hodges Hill area.

UF 271646 was collected in the Late Centenario Fauna near the Centenario Bridge area (YPA009) (MacFadden et al, 2014).

Description

The upper left molar was originally referred to Tayassuid inderterminant by

MacFadden et al., 2010 (UF 236934). It has a heavily worn crown. A recently discovered partial upper molar with little to no wear (UF 271646) preserves the crown morphology (Figure 4-7). Similar to the upper molars of Floridachoerus olseni from

Thomas Farm, UF 236934 has has four cusps in a square arrengment (APL= 17.7 mm;

TW= 18.65 mm) with two almost orthogonal valleys. Compared to the conical paracone

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and metacone, the hypocone and protocone are more transversely elongate and more crescentic (bunoselenodont dentition). A strong cingulum surrounds the entire crown with the exception of the lingual side. The occlusal aspect of the cingula is highly crenulated in the unworn LM1 (UF 271646; Figure 4-7). A barely discernible transverse valley connects the labial side with the lingual side of the crown, while the longitunidal valley is blocked anteriorly by the paraconule and posteriorly by a worn hypoconule in

UF 236064 (Figure 4-7). These structures are clear in UF 271646, as well as the distinctive conical, almost pyramidal, shape of the cusps.

Discussion

The morphology preserved in the upper M1 from the Centenario Fauna (UF

236034) closely resembles that of Floridachoerus olseni from Thomas Farm in having a crown with four conical cusps, well-developed anterior and posterior cingula and a distinctive bunoselenodont pattern characterized by distinct cristae on upper molars.

Despite that Floridachoerus sp. form Panama is similar in size to F. olseni from Thomas

Farm (M1APL: 17.71 M1TW: 18.65 for UF 236034 and M2APL: 16.92 mm; M2TW:

18.25 mm for UF V 5657, Floridachoerus olseni from Thomas Farm), the lack of more specimens precludes a more accurate allocation of these isolated fossils; consequently, they are here referred to aff. Floridachoerus sp.

Hesperhyinae n. gen. B.

Type and only known species. Hesperhyinae n. gen. B & sp. A.

Diagnosis. Hesperhyine tayassuid that differs from all members of the

Hesperhys–“C”. sociale clade in having lower molars with more inflate crowns, reduced cristid oblique, and distinct posterolingual process of metaconid blocking the transverse valleys. Differs from Stuckyhyus in having bunodont crowns, and lower molars with

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more distinctive entoconulids blocking the transverse valleys. Differs from

Marshochoerus in having a p3 with distinct anterior and posterior cingular segments, and transversely expanded talonid; m3 with transverse contriction at level of talonid notch; squarer p4 with distinct protoconid and paraconid; fused symphysis; more elongate hypoconulid lobe in m3. Further differs from Hesperhyinae n. gen. A in having larger molars and premolars, having a functional p4 paraconid, and unreduced m3 hypoconulid lobe. Further differs from “C”. occidentale (and other tayassuines) in retaining a paraconid on p4, having relatively more square molars and premolars and less reduced M3/m3. Further differs from “Prosthennops” xiphidonticus in having a functional p4 paraconid and distinct posterolabial process of the metaconid, and relatively more square molars and premolars.

Hesperhyinae n. gen. B & sp. A

Figure 4-8, Table 4-4

Holotype. UF 280424, paired mandible with left p3-m2, right p4-m3, and partial symphysis.

Referred specimens. UF 280442, right p2; and UF 281474, right m3.

Diagnosis. As for the genus.

Distribution. Only known from early Miocene (early Hemingfordian) sequences from the Panama Canal basin.

Type species. Hesperhyinae n. gen. B & sp. A.

Locality and horizon. The holotype and referred specimens were recovered from a coarse grained sequence at the PAC-4 locality (YPA086), late Centenario Fauna

(MacFadden et al., 2014) by J. W. Moreno. Although this layer produced fossils now grouped in the Centenario Fauna (MacFadden et al., 2014); the correlation between

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sequences from the PAC-4 area and those from the Centenario Bridge is based on the relative stratigraphic position to the lowermost strata (agglomerates) of the Pedro

Miguel Formation in the area (MacFadden et al., 2014). In contrast to the continental sequences with abundant paleosols cropping out in the Centenario Bridge area, the fossiliferous intervals in the PAC-4 area represent transitional to more paralic environments with lignites and conglomeratic sequences with a clear marine influence.

This sequence is correlated to the fossiliferous localities in the Centenario Area (~1 km

NNW) and therefore, the age is regarded as early Hemingfordian (MacFadden et al.,

2014).

Description

Mandible. The mandibles are slender and homogeneous below the tooth row with a distinct lateral widening below the m2 (Figure 4-8). The depth of the mandible below m1 is 24 mm (see also Table 4-2). The symphysis is strongly fused (Figure 4-8) with no evidence of suture and the transverse distance between the anterior roots of the p2s is

~17 mm. The distal part of the symphysis is not preserved; however, the location of breaks and the space anterior to the p2 does not support the presence of an alveolus for the p1; instead, this space was likely occupied by the lower canine. The posterior end of the symphysis is located below the anterior root of the p3s (Figure 4-8). The APL of the cheek teeth (p4-m3) is ~ 54 mm. Intense deformation affected the ventral part of the horizontal ramus, yet a distinct digastric fossa extends anteroposteriorly on the medial side of the horizontal ramus (Figure 4-8), ending in a distinct spine located at the ventral end of the posterior part of the symphysis. Three mental foramina are located in the labial side of each mandible. The most anterior one is located ~ 9.0 mm below the

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diastematal crest (Figure 4-8), the intermediate one is located ~14 mm below the p2 alveoli, while the posteriormost is located ~17 mm below the p4.

Lower dentition. In UF 280424, the p3 is double-rooted, its crown is oval in occlusal view (APL:12.9 mm; TW: 6.93 mm; p3APL/TW: 1.86) with similar maximum widths above the anterior and posterior roots. It has a large, conical, and undivided main cuspid (protoconid) located at the mid-point of the crown (Figure 4-8). An anterior ridge connects the apex of the protoconid with a low anterior cuspulid placed in the position of the paraconid. A distinct posterior ridge connects the apex of the protoconid with a small posterior cuspid developed on the posterior cingulid, forming two tiny cuspulids on both the labial and lingual sides of the talonid (Figure 4-8).

The p4 is double-rooted with an oval crown (APL: 12.6 mm; TW: 8.29 mm; p4APL/TW: 1.52) proportionally larger than that of the p3. It exhibits a distinct talonid notch and a low paraconid located at the same level of the talonid and with a clear occlusal wear facet (Figure 4-8). The talonid represents about 30% of the total length of the crown and its vertical height is about half that of the trigonid in lateral view. The main cuspid has a distinct longitudinal groove separating it in labial (metaconid) and lingual (protoconid) halves. A distinct cristid connects the apex of the labial half

(metaconid) with a rather weak but distinct anterior cingulid ending in a paraconid which is located anteriorly at the same level of the talonid in lateral view (Figure 4-8). The transverse valley is blocked by a strong groove running posteriorly and connecting the protoconid with a cuspulid attached to the anterolabial part of the hypoconulid (Figure 4-

8) posterior to a discontinuous transverse valley. The talonid is formed by a main posterior cuspid (hypoconulid) flanked by two distinct cuspids located on the distict

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posterior cingulid (the hypoconid lingually and entoconid labially). The hypoconid and entoconid are similar in size while the hypoconid is the largest cuspid on the talonid.

Both, entoconid and hypoconid are notched by posterolingual and posterolabial forrows forming two small cuspulids on both sides of the hypoconulid.

The lower m1 is anteroposteriorly elongate (APL: ~12.0 mm; TW: ~9.7 mm) and larger than the p4. It has four distinct, bunodont main cuspids. The trigonid and talonid are similar in relative length but the trigonid is slightly higher than the talonid (Figure 4-

8) and separated from if by a partially interrupted transverse valley. An anterior cingulid located low in the crown connects the anterolabial part of the paracone to the lingual side of the protocone. The external cuspids (metaconid and entoconid) are slightly more anteriorly placed than the protoconid and hypoconid (Figure 4-8), but the valley is nearly blocked by the junction between the entoconulid and a distinct posterolingual process of the protoconid. The wear patterns preserved on the crown of m1 suggest that the lingual cuspids (hypoconid and protoconid) are larger than the labial cuspids, and this morphology is also evident in m2 and m3. Two small cristids run posteriorly from the metaconid and protoconid converging in the posterior process of the metaconid and blocking the longitudinal valley anterior to the talonid notch (Figure 4-8). The talonid is formed by two larger posterior cuspids (hypoconid and metaconid) flanking the relatively small the entoconulid anteriorly and hypoconulid posteriorly. The hypoconulid is similar in size to the entoconulid and is located at the intersection between the midline of the crown and the posterior cingulid. Small cingular segments restricted to the anterolabial part of the crown are on the anterolabial part of the lower molars. A small but distinct ectostylid is present at the opening of the transverse valley on the lower molars. The m2

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is similar in morphology to the m1; however, it is the largest among the molar series

(APL: ~13.0 mm; TW: ~12.2. mm). The m3 is more elongate than the m2 (APL: ~15.0 mm; TW: ~12.6. mm), and has a distinctive transversal constriction at the level of the talonid notch (Figure 4-8). The morphology on the anterior part of the crown is similar to that of the m1 and m2; however, the posterior part has a distinctive elongate lobe with a hypoconulid flanked by three distinct small cuspids and blocking the posterior transverse valley. The APL measured posterior to the anterior transverse valley to the posterior end of the hypoconulid lobe represents about 65% of the total anteroposterior length of the crown. A distinct ectostylid is blocking the labial aperture of the transverse valley (Figure 4-8).

Comparisons

The mandible of Hesperhyinae n. gen. B & sp. A is relatively shallower than that of similarly sized Tayassu tajacu and “C”. occidentale (FAM 73660) but relatively deeper than that of Hesperhyinae n. gen. A & sp. A from the Lirio Norte and Centenario faunas

(Table 4-2). In contrast to that of Marshochoerus socialis, Hesperhyinae n. gen. A & sp.

A, and Hesperhyinae n. gen. A & sp. B, the symphysis of Hesperhyinae n. gen. B & sp.

A is strongly fused (Figure 4-8) with no evidence of suture. The strongly fused symphysis of Hesperhyinae n. gen. B & sp. A resembles that of Wrightohyus,

Lucashyus, and Hesperhys; however, it differs from these early Miocene hesperhyines in having more inflated and acuminate crowns on the lower molars, and a distinctive multicuspid talonid on p4. Despite of having more bunodont crowns with distinct entoconulids, Hesperhyinae n. gen. B & sp. A is similar to other hespehynes (except

Hesperhyinae, gen. A. from Panama) in having a completely fused symphysis; p3 with anterior and posterior cungulids with the posterior heel being much more expanded

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transversely; and p4 with distinct protoconid and metaconid separated by a longitudinal furrow and a functional paraconid that is located along the midline of the tooth.

Moreover, the transverse contriction at the level of the talonid notch on the m3 is remarkably similar to that present in S. siouxensis (Peterson, 1906:plate XXXIV).

Nonetheless, Hesperhyinae n. gen. B & sp. A has a relatively wider and more transversely expanded talonid on p3 with a posteriorly restricted cingulid.

Hesperhyinae n. gen. B & sp. A differs from Arikareean Marshochoerus socialis from Oregon, and Hesperhyinae n. gen. A & sp. A and early Hemingfordian

Hesperhyinae n. gen. A & sp. B from Panama in being larger (Table 4.2; Figure 4-3); having a squarer p4 with a distinct longitudinal furrow between protoconid and metaconid; a relatively deeper postgastric sulcus that it is connected to a distinct mental spine in the posteroventral end of a strongly fused symphysis; more elongate crowns with more distinct entoconulids blocking the transverse valleys on lower molars, and a more elongate hypoconulid lobe on m3. It is similar to Arikareean M. socialis in having an m2 comparable in width to the m3, and in retention of a functional paraconid on p4.

Although similar to “Prosthennops” xiphidonticus (= “C”. proterva of Woodburne, 1969;

USNM 243996) in the degree of molarization of the p4 talonid; the relative elongation of the hypoconulid lobe on m3; the presence of a paraconid on p3, the connection of the hypoconid with the entoconulid on lower molars only occurs after middle wear.

Furthermore, Hesperhyinae n. gen. B & sp. A has a relatively shallower mandible than that of “P”. xiphidonticus (Table 4-2).

Hesperhyinae n. gen. B & sp. A is similar to the late Arikareean Pope Creek sp. from Delaware (Wright and Eshelman, 1987) in lacking the steep-sided protoconids on

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lower p2 and p3, and having a similar elongation of the m3 (Table 4-2), However, the hypoconulid lobe of m3 has a different configuration. In Hesperhyinae n. gen. B & sp. A, the hypoconulid lobe exhibits a distinct transverse constriction at the level of the talonid notch whereas the elongation is more homogeneous along the posterior part of the crown in other early Miocene tayassuids reaching the maximum in the Pope Creek specimen (Table 4-2). While similar to the Barstovian “Cynorca”. occidentale in having a relatively deeper mandible below m1, a p4 with a distinct posterolabial process on metaconid, a distinct longitudinal furrow between the protoconid and entoconid on p4, and a m2 relatively larger than m1 and m3; the p4 talonid of Hesperhyinae n. gen. B & sp. A has three cuspids (instead of two), the p4 is relatively more square in occlusal view (Table 4-2), and more importantly, retains a functional paraconid.

The precise allocation of this taxon from Panama is problematic given the clear similarities between the dentitions recovered from the PAC-4 area and other tayassuines like “Cynorca” occidentale and Dyseohyus; however, it also exhibits morphologies present in older hesperhyine tayassuids. For example, it exhibits dental morphologies that link it to the Hesperhys–M. socialis clade like the retention of a paraconid on p4, unfused symphysis, and having a lower m2 that is similar in width to the m3 but disitinctively larger than the m1. On the other hand, Hesperhyinae n. gen. B

& sp. A exibits dental morphologies only present in younger tayassuines (e.g.

“Prosthennops” xiphidonticus and “C”. occidentale) that include: a lower p4 with a distinct longitudinal furrow between protoconid and metaconid and a multicuspid talonid, crowns on lower molars with distinct conulids blocking the transverse valleys, and a relatively deeper mandible. Surprisingly, the morphologies in which Hesperhyinae n.

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gen. B & sp. A differs from “P”. xiphidonticus are the same morphologies shared with the type of the hesperhyine Stuckyhyus siouxensis (co-ossification of the symphysis; the relative size of the p3 talonid; retention of a paraconid on p4; and the distinctivetransverse constriction of the m3 hypoconulid lobe located at the level of the talonid notch). Given the fact that the skull and upper dentition of this new taxon from

Panama are not known, and that bunodonty evolved independently in different mammalian groups, it seems more parsimonious to refer UF 280424 to a new monospecific genus (Hesperhyinae n. gen. B & sp. A) that, although retaining plesiomorphic morphologies (e.g. presence of a paraconid on p4), exhibits the more bunodont crowns on lower molars with more distinct conulids blocking the longitudinal valley, and a partially molarized anterior dentition of more derived tayassuines.

Phylogenetic Analysis

To evaluate the phylogenetic relationships between these new early Miocene bunodont tayassuids and the Tayassuinae, I performed a cladistic analysis of 12 tayassuid taxa from tropical and subtropical areas of North America, with the primitive tayassuid Perchoerus probus from the Chadronian of Texas and the Great Plains as the outgroup. Tayassuids tend to be distinguished by a combination of cranial and dental features; however, most fossil tayassuids found outside the Great Plains are not known from specimens that preserve cranial morphology, therefore, I focus my analysis on taxa known from partial skulls, and/or dentitions with associated premolars. Tayassuids represented in early Miocene assemblages lacking upper/lower premolars were excluded. I scored primarily dental (19) and cranial (5) characteristics (Appendix 4-2) in the data matrix (Appendix 4-3), which includes characters that are unordered and equally weighted. Morphological data were compiled from the study of specimens

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(casts) housed in the FLMNH collection and a literature review. Characters not known for a taxon were coded as missing. Data were compiled in Mesquite version 2.72

(Maddison and Maddison, 2009) and then analyzed under the parsimony criterion using the branch and bound algorithm of PAUP version 4.0b10 (Swofford, 2003). My analysis resulted in two equally most parsimonius cladograms (MPT) with a tree length of 43 steps, a consistency index (CI) of 0.605, a retention index (RI) of 0.712, and a homoplasy index (HI) of 0.395.

Results summarized in the consensus tree (Figure 4-9) resemble the relationships proposed by Wright (1998) between the Hysperhys -“C”. sociale clade and the

Tayassuinae. I recovered a paraphyletic Hesperhys -“C.” sociale clade (node 1) that includes a late Arikarrean?-early Hemingfordian Stuckyhyus siouxensis-Floridachoerus olseni clade (node 2) based on the presence of a continuous cingulum on the upper P4

[21(1)]. The late Arikareean Marshochoerus socialis from Oregon appears as the sister taxon of a clade that includes Hesperhyinae, gen. A, the Pope Creek tayassuid, and the tayassuines (node 3) based on having a dorsal media sulcus on maxillopalatine labyrinth [1(1)], postdental process of palate extending posterior to M3 [2(1)], and a P3 cingulum restricted to the posterior part of the crown [7(1)].

The more bunodont tayassuids, the late Arikareean Marshochoerus socialis and

Hesperhyinae, gen. A represent the sister group of the Pope’s Creek tayassuid from

Maryland (Wright and Eshelman, 1987) based on having an M3 with principal cusps not separated by accessory cusps [4(1)], lacking a paraconid on lower p4 [11(1)], and having a distinct posterolabial process of metaconid on lower p4 [17(1)]. In fact, my results suggest that this late Arikareean tayassuid from Maryland is the sister taxon of

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the tayassuinae with “C”. occidentale, as the basalmost member, based on having a metaconule on P4 [5(1)], and a P3 cingula located posterolabially with or without cuspules [7(2)]. Surprisingly, the tayassuine “Cynorca” occidentale appears as the sister taxon of late early Miocene tayassuines, including Hesperhyinae n. gen. B & sp. A, based on on having a p4 talonid with more than two cuspids [12(1)]. Finally,

Hesperhyinae n. gen. B & sp. A appears as the sister taxon of Barstovian

“Prosthennops” and Dyesohyus (node 8) based on having a lower p3 with more than two cuspids on the talonid. A politomy is present in node 9 in my strict consensus; however, the Barstovian tayassuines “Prosthennops” xiphidonticus , “P”. niobrarensis and Dyesohyus fricki are grouped by having an atrium with a compartmentalized maxillopallatine labyrinth [3(1)].

In summary, my results suggest that fossil bunodont tayassuids from Panama are represented by the late Arikareean-early Hemingfordian hesperhyines (Hesperhyinae n. gen. A & sp. A and Hesperhyinae n. gen. A & sp. B) with the early Hemingfordian

Hesperhyinae, gen B. et. sp. nov A recovered as member of the Tayassuinae. Based on the resulting topology and the age for the Centenario Fauna, Hesperhyinae n. gen. B & sp. A might represent the oldest tayassuine in North America. However, it seems obvious that the discovery of the upper dentition (or skull) of Hesperhyinae n. gen. B & sp. A might alter the outcome of this analysis given the overall low resolution of my analysis within Tayassuinae. Nonetheless, Hesperhyinae n. gen. B & sp. A clearly exhibits at least one synapomorphy of the tayassuine clade (a p4 with multicuspid talonid) while retaining the plesiomorphic condition of having a paraconid on the lower p3 and p4.

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Discussion

Early Miocene tayassuids are represented in Panama by three hesperhyne genera: the bunodont Hesperhyinae, gen. A (including Hesperhyinae n. gen. A & sp. A and Hesperhyinae n. gen. A & sp. B) and Hesperhyinae n. gen. B & sp. A, and the more lophodont Floridachoerus sp. Hesperhyinae n. gen. A & sp. Afrom the late Arikareean

Lirio Norte L. F. is a small bunodont peccary that closely resembles the Arikareean

Marschochoerus socialis; however, it exhibits incipient development of the conulids on lower molars, a reduction of the paraconid in the p4, a relatively more reduced m3, and an unfused symphysis. Furthermore, the lower premolars (p2 and p3) are simple and lack any kind of anterior or posterior cuspids. Although not represented by upper premolars, this new species of hesperhyine marks the arrival of bunodont tayassuids to tropical areas of southern Central America.

Re-examination of the partial skull and partial lower dentitions of Hesperhyinae n. gen. A & sp. B ( = “C”. occidentale MacFadden et al., 2010) from the early Centenario

Fauna (Upper Culebra Formation) confirms that despite having more distinct conulids on the molars than Hesperhyinae n. gen. A & sp. A from the Lirio Norte L. F., also exhibits distinctive tayassuine morphologies present in “C”. occidentale, namely, the development of a supraatrial chamber in the maxillopallatine labyrinth and a M2/m2 that is relatively larger than M1/m1 and M3/m3, Hesperhyinae n. gen. A & sp. B lacks relevant dental and cranial tayassuine morphologies like the presence of a postprotoconal groove on P4 and the reduction of the P1. Consequently, I refer these fossils from the early Centenario Fauna and those partial lower dentitions from the Lirio

Norte L. F. to a new hesperhyne genus, Hesperhyinae, gen. A. This new genus encompasses fossils from the Late Ariakareean Lirio Norte L. F. Hesperhyinae n. gen. A

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& sp. A) and fossils from the early Centenario Fauna (Hesperhyinae n. gen. A & sp. B) that, while remarkably similar in many dental aspects, shows clear differences in the relative size of the m3 hypoconulid lobe that warrant my specific designations. Only the discovery of either the anterior lower premolars for Hesperhyinae n. gen. A & sp. B or the anterior upper dentition for Hesperhyinae n. gen. A & sp. A will ratify this initial taxonomic interpretation.

Re-examination of UF 236934 (tayassuid incertae sedis of MacFadden et al.,

[2010]) and a newly recovered partial molar, UF 271646, corroborate that a hesperhyine tayassuid, closely related to the early Hemingfordian Floridachoerus olseni, inhabited tropical forested areas of Panama during the early Hemingfordian.

Partial tayassuid dentitions from the upper Cucaracha Formation (late Centenario

Fauna) are referred to Hesperhyinae n. gen. B & sp. A. based on morphologies present in the more derived tayassuines (more inflated crowns on lower molars with entoconulids blocking the longitudinal valleys). Although the lack of upper premolars weakens my interpretations regarding its possible tayassuine affinities, Hesperhyinae n. gen. B & sp. A has a completely fused symphysis; a p3 with distinctive paraconid and a transversely expanded talonid; and a p4 also with paraconid. Although these morphologies are also present in older hysperhyine tayassuids (e.g Hesperhys,

Wrightohyus, Stuckyhyus, Lucashyus), the unreduced m3 hypoconulid lobe with a transverse constriction is more similar to the more bunoselenodont hysperhyne

Stuckyhyus siouxensis from the Great Plains. My taxonomic interpretations suggest that the increase in relative size of conulids observed in the tropical early Miocene tayassuids might have been a response to coping with new tropical forested habitats

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with different food resources not available in higher latitudes. Consequently, late

Arikareean populations of hesperhyines closely related to more temperate taxa like

Marshochoerus (e.g. to Hesperhyinae n. gen. A & sp. A) arrived to the marginal volcanic tropical terrains of Panama as partakers of the colonization of the recently formed peninsula connecting southern Mexico with the Panama Canal basin. By the early

Centenario Fauna (~ latest Arikareean), hesperhyines (Hesperhyinae n. gen. A & sp. B) had started to gain a more bunodont dentition by adding a series of conulids on lower molars while retaining a pneumatic (plesiomorphic) maxillopalatine labyrinth in the skull.

Although regarded as cautious, this interpretation suggests that this early Miocene change in tayassuid tooth morphology is a response to a shift in diet while inhabiting more forested areas with a distinctive floral composition. In contrast to the niches present in the Gulf Coast and Mexico dominated by temperate floras, this early Miocene tropical niche is characterized by a tropical rain forest with Gondwanan (South

American) phytogeogeographic affinities (Jaramillo et al., 2014). This interpretation also reveals a new scenario for the diversification of tropical tayassuids that is consistent with the drastic changes in the landscape that followed the colonization of the tropical areas of southern North America during the earliest Neogene.

The most remarkable evidence of morphological change is observed in the mandibles and lower dentition of to Hesperhyinae n. gen. B & sp. A. from the late

Centenario Fauna (early Hemingfordian). Despite that Hesperhyinae n. gen. B & sp. A has more bunodont molars (with distinctive entoconulids), and more complex lower premolars (with additional cusps on the talonid) than Marschochoerus and

Hesperhyinae, gen. A, this hesperhyine tayassuid has a transversely expanded talonid

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on p3, a distinct and functional paraconid on p4, a completely fused symphysis, and a distinctive occlusal morphology on the m3 hypoconulid lobe. This constriction is only observed in the hyspehyine Stuckyhyus siouxensis, an early Hemingfordian bunoselenodont tayassuid only known from Nebraska (Peterson, 1906). This observation, although preliminary, suggests that bunodont crowns evolved independently in different tayassuid clades during periods of intense phytogeographic change after colonizing the more tropical and wetter habitats that prevailed in Panama during the earliest Hemingfordian (Graham, 1985, Graham, 1988a; Graham, 1988b;

Retallack and Kirby, 2007; Jaramillo, et al., 2014). However, the occurrence of an early

Arikareean bunodont tayassuid in southern Mexico confirms that bunodont crowns are present in peccaries inhabiting transitional and coastal environments at least since the late Oligocene. Although the inclusion of the early Arikareean Simojovelhyus in my phylogenetic analysis was not possible, it seems reasonable to hypothesize that this small tayassuid is more closely related to tayassuines than any coeval and more bunoselenodont species of Perchoerus (e.g., Perchoerus probus). Once the taxonomic revision of basal late Oligocene tayassuids is utterly achieved, the hypotheses regarding the tempo and mode of evolution of late Oligocene bunodont forms and the early Miocene tayassuines will be clarified.

Early Miocene tayassuid paleobiogeography. To clearly identify dispersal scenarios during the early Miocene in southern North America, the paleobiogeography of more generalistic ungulates like tayassuids is useful. Bunodont artiodactyls (e.g.

Hesperhyinae n. gen. A & sp. A) are more generalistic browsers (omnivores); therefore, their dispersal into new terrains is less influenced by the structure of the habitat and

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likely enhanced by the continuity of a land connection leading to new or relatively similar ecological niches. Similarities in the bunodont dentition of the tayassuids from the early

Centenario Fauna and coeval sequences from Maryland suggest that Hesperhyinae n. gen. A was the only Panamanian ungulate able to rapidly colonize higher latitudes during the early Hemingfordian. This distinct pattern, not observed in any other ungulate from Panama, can be explained by linking dispersal potential (land connections) to food resources. For instance, palynological work carried out in the lower part of the Calvert

Formation near the Pollack Farm area confirmed that the habitat was dominated by temperate or warm-temperate taxa, with low frequencies of exotic subtropical or tropical taxa similar to the floral composition of what is today the coastal region of Georgia and northern Florida. Furthermore, the relative abundance of tree and shrub pollen and the rarity of herbaceous pollen indicated closed habitats (dense forests) developed in coastal (paralic) shallow marine to coastal environments (Groot, 1998). Therefore, bunodont tayassuids similar to Hesperhyinae n. gen. A & sp. B from Panama were widely distributed along transitional and coastal environments of North America during the early Hemingfordian. They inhabited a variety of transitional to paralic environments ranging from tropical latitudes (Panama) and reaching the more temperate areas of the

Cheseapeake Bay (Emry and Enshelman, 1998). This rapid colonization of transitional environments in higher latitudes was likely controlled by the distribution of transitional environments developed along coastal areas of North America (tidal flats and mangrove habitats) during the early Hemingfordian. Furthermore, this spreading into subtropical and temperate habitats, although not neccessarly linked to specific diet preference in these omnivores, was likely favored during warm intervals that followed the beginning of

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the Miocene that led to the Mid-Miocene Climatic Optimum c.a. 15 Ma (Zachos et al.,

2001; 2008). Although there is no geological evidence supporting paralic and transitional environment in the fossiliferous assemblages from Central Florida, this interpretation would explain the absence of bunodont tayassuids in the intensively sampled Hemingfordian localities where terrestrial fossils are associated to distinct karstic landscapes.

Unfortunately, the taxonomic resolution for many of the Arikareean isolated dentitions initially referred to “Cynorca” (now Marshochoerus) does not allow clarifying the relationships between late Arikareean tayassuids from the Gulf Coast (Albright,

1999; O’Sullivan, 2003; Frailey, 1969; Patton, 1969). It seems clear that the correct allocation of these partial dentitions only can be achieved after new and more complete fossils are recovered. Nonethless, now that the taxonomic relationships among the early

Miocene tayassuids is better understood, and also that the paleophytogeograhic evolution of southern North America is being discovered, further studies will reveal details regarding the early evolution of Neogene tayassuines in tropical and subtropical areas of America prior to the beginning of the Great American Biotic Interchange during the Pliocene.

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Figure 4-1. Location and biochronology of the Oligocene-Miocene tayassuid-bearing fossil faunas discussed in this study. See text for details. Abbreviations: Ar, Arikarrean Land Mammal zone; Ba, Barstovian NALMA; Cl, Clarendonian NALMA; E, early; He, Hemingfordian NALMA; Hh, Hemphillian NALMA; L, late; L.F, Local Fauna; Ma, Mega Annum.

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Figure 4-2. Upper and lower dentition of Hesperhyinae n. gen. A & sp. A from the Lirio Norte Local Fauna (L. F.), Upper Las Cascadas Formation, Panam. A, UF 267027, left DP3; B, UF 275279, right DP4 C, UF 281140, partial M2; D-F, UF 280424, holotype in occlusal, labial, and lingual views. Arrows point anterolingually.

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Figure 4-3. Scatter plot of the tooth dimensions (in natural log scale) measured the late Oligocene to early Miocene tayassuids from southern North America and Panama discussed in this chapter. Abbreviations: B, Hesperhyinae, gen B. et. sp. nov A; “C”, “Cynorca”; M, Marshochoerus; “P”, “Prosthennops”; T, Tayassu.

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Figure 4-4. Partial skull (holotype) of Hesperhyinae n. gen. A & sp. B from the early Centenario Fauna. A, CT surface model of UF 224400, lateral view; B, occlusal, C, oblique, D, posterior view. E, parasagittal section of UF 224400 showing the morphology of the maxillopalatine labyrithm and the nasal area. F, transverse section at the level of P2 of UF 224400 showing the morphology of the anterior part of the maxillopalatine labyrithm; G, transverse section at the level of M1; H, transverse section at the level of M3. Abbreviations: apmxl, anterior protuberance of maxillopalatine labyrinth; iof, infraorbital foramen; max, maxilla; mc, maxillary canal; mxl, maxillopalatine labyrinth; pal, palatine; pc, palatine canal; pcf, plesiochoanal fossa; pf, palatine foramen; pvc, paravomeronasal capsule; vom, pneumatic part of vomer.

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Figure 4-5. Detail of the upper dentition of UF 224400, partial skull of to Hesperhyinae n. gen. A & sp. B from the early Centenario Fauna, occlusal view. Abbreviations: cf, canine fossa; dc, diastematal crest; pcf, plesiochoanal fossa; pf, palatine foramen.

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Figure 4-6. Lower dentition of Hesperhyinae n. gen. A & sp. B from the early Centenario Fauna, Upper Culebra Formation, Panama Canal area A, UF 237885, left mandible with m1-m2 in occlusal view; B, lingual view; C, labial view; D, UF 237884, left mandible with m1 and symphysis in occlusal view; E, lingual view; F, labial view; G, UF 142115, left m3 in occlusal view; H, labial view; I, lingual view. Arrows point anterolingually.

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Figure 4-7. Partial upper molars of aff. Floridachoerus sp. from the early Centenario Fauna (upper Culebra Formation), Panama Canal area. A, UF 236934, left M1 or M2, occlusal view; B, UF 271646, right M1 or M2 (partial), occlusal view.

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Figure 4-8. Lower dentition of Hesperhyinae n. gen. B & sp. A from the late Centenario Fauna, PAC-4 area, Panama Canal. A, UF 280424, paired mandibles with right p2-m3, left p3-m2 and partial symphysis in occlusal view; B, in lateral view.

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Figure 4-9. Hypothetical relationships of the early Miocene bunodont tayassuids from North America based on a 24-character matrix with Perchoerus probus as the outgroup. Strict consensus tree resulting after the analysis under the parsimony criterion using the branch and bound algorithm of PAUP version 4.0b10 (Swofford, 2003) (Tree length = 43; CI = 0.605; RI = 0.712; HI = 0.395). At each node (bold italized numbers) the supporting unambiguous synapomorphies are: 1, [19(1)]; 2, [21(1)]; 3, [1(1)], [2(1)], [7(1)]; 4, [4(1)], [11(1)], [17(1)]; 5, [()]; 6, [5(1)], [7(2)]; 7, [12(1)]; 8, 16[1]; 9, 3(1), 9(1).

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Table 4-1. Summary table of dental measurements (in mm) of to Hesperhyinae n. gen. A & sp. A from the Lirio Norte Local Fauna (Upper Las Cascadas Formation). Abbreviations: APL, anterior-posterior length; TW, transverse width; TWhyd, hypoconulid transverse width; S, standard deviation; V, index of Variance.

Tooth Position N Range Mean S V p3 (APL) 1 9.90 9.90 0.155 1.90 p3 (TW) 2 5.60 5.60 0.523 13.99 p4 (APL) 2 10.4-11.51 10.50 0.844 10.623 p4 (TW) 2 7.6-8.14 7.62 0.442 9.16 m1 (APL) 1 10.65 10.65 - - m1 (TW) 1 8.60 8.60 - - m2 (APL) 3 12.80-13.90 13.35 - - m2 (TW) 3 10.69-11.90 11.39 - - m3 (APL) 2 14.70-15.05 14.82 - - m3 (TW) 2 8.99-9.16 9.75 - - m3 (TWhyd) 2 5.30-5.45 5.37 - -

DP3 (APL) 1 8.85 8.85 - -

DP3 (TW) 1 6.78 6.78 - -

DP4 (APL) 1 10.51 10.51 - -

DP4 (TW) 1 9.97 9.97 - -

M2 (APL) 1 11.5 11.5 - -

M2 (TW) 1 10.85 10.85 - -

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Table 4-2. Summary of the comparative measurements (in mm) of the tayassuid dentitions and skulls discussed in this chapter. Abbreviations: (*), type specimens Hesperhyinae Hesperhyinae Hesperhyinae “Cynorca” Marshochoerus Stuckyhyus n. gen. A & n. gen. A & n. gen. B & occidentale* socialis* siouxensis* sp. A* sp. B* sp. A* Relative depth of mandible below p4 or ~119% ~90 % ~ 95% > 100 % ~130% > 100 % m1 (% m1-m2 APL) p4-m3 APL 42.38 48.69 ~ 50.0 54.84 47.64 ~71.0 P2-M3 APL 53.42 NA 59.6 NA 60.10 ~ 80.0 P2-P3APL/M1 1.73 NA 1.90 NA 1.53 ~1.5 APL M3 APL/M1 1.2 NA 0.9 NA 0.97 1.2 APL m3 APL/m3hyd 3.16 2.9 2.8 3.6 2.5 ~3.2 APL Height of the nasals above the P4 - - 66% - - ~86% (% P2-M3 APL) p4APL/p4TW 1.70 1.46 NA 1.60 1.75 1.55 m3APL/m3TW 1.65 1.63 1.42 1.40 1.48 1.64

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Table 4-2. Continued Dyesohyus Simojovelhyus Tayassu Pope’s Creek “Prosthennops” stirtoni* pocitoensis* tajacu specimen xiphidonticus

Relative depth of mandible below p4 NA ~94 % ~150 % ~100 % ~130% or m1 (% m1-m2 APL)

p4-m3 APL 76.78 NA 52.79 46.67 65.3 P2-M3 APL 72.0 NA 64.0 NA 76.3 P2-P3APL/M1 1.54 NA 1.62 1.77 1.7 APL M3 APL/M1 APL 1.4 NA 1.48 NA 1.4

m3 APL/m3hyd NA 2.2 2.38 NA ~2.9 APL

Height of the nasals above the > 91%- - 110% - - P4 (% P2-M3 APL)

1.43 NA 1.30 1.55 1.45 p4APL/p4TW 1.65 1.70 1.58 1.80 1.72 m3APL/m3TW

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Table 4-3. Summary table of dental measurements (in mm) of to Hesperhyinae n. gen. A & sp. B from early Centenario Fauna (upper part of the Culebra Formation). Abbreviations: Alv, measured on alveoli; APL, anterior-posterior length; TW, transverse width; TWhyd, hypoconulid transverse width; S, Standard deviation; V, index of Variance. Hesperhyinae n. gen. A & sp. B Upper Molars Tooth Position N Range Mean S V C1 (APL) alv 7.2 7.2 C1 (TW) alv 5.5 5.5 P1 (APL) 2 4.62-4.83 4.72 0.148 3.14 P1 (TW) 2 2.63-2.66 2.64 0.021 0.034 P2 (APL) 2 9.3-9.45 9.37 0.106 1.13 P2 (TW) 2 5.78-5.88 5.83 0.070 1.212 P3 (APL) 2 10.98-11.12 11.05 0.098 0.895 P3 (TW) 2 7.27-7.5 7.38 0.162 2.202 P4 (APL) 2 8.76-8.9 8.83 0.098 1.121 P4 (TW) 2 10.05-10.12 10.08 0.049 0.491 M1 (APL) 2 10-71-10.73 10.73 0.00752 0.065 M1 (TW) 2 11.24-11.64 11.44 0.282 2.47 M2 (APL) 2 11.63-11.74 11.68 0.077 0.665 M2 (TW) 2 12.9-13.03 12.96 0.091 0.709 M3 (APL) 2 9.57-9.67 9.62 0.071 0.735 M3 (TW) 2 10.29-10.58 10.43 0.205 1.96

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Table 4-3. Continued Hesperhyinae n. gen. A & sp. B Lower Molars

Tooth Position N Range Mean S V

m1 (APL) 2 10.48-11.6 11.04 0.791 7.17

m1 (TW) 2 7.7-8.51 8.105 0.572 7.06

m2 (APL) 1 12.02 12.02 - -

m2 (TW) 1 9.31 9.31 - -

m3 (APL) 1 14.4 - - -

m3 (TW) 1 10.11 - - -

m3 (TWhyd) 1 6.32 - - -

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Table 4-4. Summary table of dental measurements (in mm) of to Hesperhyinae n. gen. B & sp. A from late Centenario Fauna (upper part of the Cucaracha Formation). Abbreviations: Alv, measured on alveoli; APL, anterior- posterior length; TW, transverse width; TWhyd, hypoconulid transverse width; S, Standard deviation; V, index of Variance. Hesperhyinae n. gen. B & sp. A Lower Molars

Tooth Position N Range Mean S V

p2 (APL) 1 10.20 10.20 - -

p2 (TW) 1 4.99 4.99 - -

p3 (APL) 1 12.09 12.09 - -

p3 (TW) 1 6.93 6.93 - -

p4 (APL) 3 12.6-12.87 12.73 0.583 5.17

p4 (TW) 3 8.14-8.29 8.21 0.311 4.66

m1 (APL) 2 11.90-12.01 11.95 0.354 3.22

m1 (TW) 2 9.70-9.84 9.77 0.476 5.09

m2 (APL) 2 13.30-13.56 13.43 0.524 4.38

m2 (TW) 2 12.22-12.24 12.23 0.344 3.25

m3 (APL) 2 15.70-15.84 15.77 0.789 4.46

m3 (TW) 2 11.16-11.18 11.17 0.196 1.80

m3 (TWhyd) 2 5.33-5.35 5.34 0.318 4.95

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CHAPTER 5 ARTIODACTYL FAUNAL COMPOSITION AND PALEOECOLOGY

A total of 645 individual and associated ungulate teeth from Panama were prepared and examined (Appendix K). Fossil were collected from 26 localities along the

Panama Canal that produced mammalian dental remains identifiable to species level

(Table 5-1). Localities included twenty localities for the late Centenario Fauna (CF), three from the early Centenario Fauna and three localities from the Lirio Norte Local

Fauna (LNLF). To warrant an accurate specific designation, isolated teeth were compared to more complete specimens and holotypes. I document the occurrence of 22 ungulate species (Table 5-1) in Panama that include four species of perissodactyls

(equids, rhinocerotids, and chalichotheres), which are reported but not described here and 18 artiodactyl species. Relative abundance for a given species was calculated for each assemblage based on the total minimum number of individuals (MNI) identified in the Panamanian ungulate sample. Artiodactyl relative abundance for both fossil assemblages is represented by the ratio between the MNI and the total count of ungulate individuals for each assemblage (Table 5-1).

Two main assumptions are implicit in the calculation of the different diversity indices discussed below: 1) taphonomic bias: localities from the Culebra and Cucaracha

Formations (CF) encompass lithologies (e.g. conglomerates, fine to coarse sandstones, and claystones) representing flood plain environments with evidence of paralic sedimentary environments for the early Centenario Fauna (Montes et al., 2012;

MacFadden et al., 2014). In contrast, fossiliferous localities from upper Las Cascadas

Formation (LNLF) include volcanic (effusive) lithologies that incorporated mammalian remains into fluvial sequences developed on coarse-grained volcanic breccias with no

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evidence of transitional or extensive flood plains environments. This sedimentological interpretation is further supported by the different ratios between specimens representing terrestrial mammalian taxa and specimens representing riverine taxa (e.g. fishes) recovered from more prolific localities from the Centenario Fauna (see below); 2) collecting effort: the majority of the fossils were collected by field crews focused on two highly productive fossiliferous localities somehow overlooking localities where the terrestrial fossils are rare or poorly represented. Despite overall low intensity sampling efforts and the rarity of the terrestrial fossils, localities from the early Centenario Fauna

(Upper Culebra Fm) are included in the calculations because fossils from these localities represent evidence of mammalian communities inhabiting transitional to paralic sedimentary environments (Rincón et al., 2015).

Rarefaction curves. Individual rarefaction curves suggest that most of the species are undersampled when looking at the occurrence of taxa in a single locality

(Figure 5-1); however, in order to compare the species richness of the fossil assemblages from Panama, the species-level ungulate relative abundances were pooled as two single and discrete fossiliferous assemblages. The resulting relative abundances of ungulate taxa were then rarefied in order to establish a bottom line for comparison between the two assemblages (Figure 5-2). Occurrence data was rarefied using PAST 3.2.1 (Hammer et al., 2001).

Discussion. A total of 50 ungulate individuals (MNI) were identified based on the occurrence of different tooth positions in the late Arikareean Lirio Norte L. F. (Appendix

L). The ungulate faunal composition (Table 5-1) of the Lirio Norte L. F. is dominated by equids (30%), followed by floridatraguline camels (28%), and moschids (10%). The

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remaining 22% is represented by anthracotheres (2%), protoceratids (8%) and tayassuids (12%). In contrast, a total of 77 ungulate individuals (MNI) were identified in the early Hemingfordian Centenario Fauna (Appendix L). Protoceratines (Paratoceras spp) represents ~29% of the ungulate individuals recovered from the localities included in the Centenario Fauna (Upper Culebra and Cucaracha Fms). Tayassuids represent

~13% while perissodactyls (rhinoceroses and equids) represent ~32% of the maximum number of individuals calculated. Other artiodactyl groups (e.g. tayassuids) represent

~16% of the recovered identifiable fossils. Surprisingly, the relative abundance of moschids (blastomerycines) showed little variation after comparing both assemblages representing approximately 10% of ungulates in each assemblage.

While taphonomic and sampling biases were not exhaustively assessed, the two faunal assemblages were compared in terms of faunal (species richness) composition and relative abundance of ungulate taxa to broadly characterize faunal similarity.

Biodiversity indexes are summarized in Table 5-2. Dominance values (1 - Simpson index) calculated based on the relative abundances of ungulate groups suggests that the CF include ungulate taxa that are more equally represented in the assemblage than taxa represented in the slightly less diverse LNLF (Figure 5-2). Values for the Simpson index for the LNLF are approximately 10% less than the values calculated for the CF suggesting that the dominant taxa in the CF (protoceratines) are relatively more abundant than the dominant taxa (parahippine horses and flordiatrguline camels) of the

LNLF. Shannon Index values (Table 5-2) for the LNLF are less than values calculated for the CF therefore implying that there are more taxa represented by few individuals in the CF than in the LNLF. Menhinick’s richness index values for the LNLF confirm that

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despite being represented by a smaller sample size (MNI= 50), the LNLF is relatively more diverse than the CF (MNI=77). Equitability values (Shannon diversity divided by the logarithm of number of taxa) suggest that the LNLF assemblage includes individuals that are more equally divided among the taxa present in the Panamanian sample than the individuals identified in the CF. Finally, Berger-Parker values suggest that parahippine horses, the dominant taxon for the LNLF (followed by the floridatraguline

Aguascalientia), are relatively more abundant than protoceratine protoceratids, the dominant taxon in the CF (Table 5-1). In general, the species richness of the Centenario

Fauna and the Lirio Norte L. F., despite representing two distinctive sedimentary environments (volcanic areas vs. low land coastal plains and mangroves) are similar.

However, it seems that there are still many species yet to be found given the heterogeneity of the Panamanian early Miocene sediments from the Panama Canal.

Although fossils are sparse, the upper part of the Culebra Formation (early Centenario

Fauna) represents transitional and deltaic environments with species not reported in fossiliferous localities of the Cucaracha Formation (Late Centenario Fauna). Similarly, selective browsers with elongated snouts (e.g. Aguascalientia spp. and

Floridatragulinae gen et. sp. nov) are the most common artiodactyls found in the Lirio

Norte area (Lirio Norte Local Fauna) while mixed feeders, with moderately elongate snouts (protoceratines), are the most common browsers in the Centenario Fauna.

Although likely affected by taphonomic and sampling biases, this pattern clearly confirms that tropical habitats intensively affected by volcanic products were colonized during the late Arikareean by ungulates adapted to more open habitats like the selective feeder Aguascalientia, mesodont to incipiently hypsodont parahippine horses (Rincón et

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al., 2015b), and basal floridatragulines similar to Oxydactylus longipes

(Floridatragulinae gen. et. sp. nov). The remarkable absence of riverine taxa (eg. fishes) supports the idea that the upper part of the Las Cascadas Formation represents an ancient valley developed in volcanic terrains with no evidence supporting an extensive flood plain in Panama, at least in the Lirio area. In contrast, the more closed forested habitats inferred for the Centenario Fauna (Jaramillo et al., 2014) were dominated by tropical endemic mixed feeders like protoceratine protoceratids with distinctive postcranial morphologies consistent with less-cursorial morphological adaptations

(Rincón et al., 2015). Fishes are remarkably more common in all localities of the

Centenario Fauna, including those of the upper Culebra Formation and the Cucaracha

Formation.

Early Miocene ungulate paleobiogeography. Two distinct periods of tectonic and volcanic activity coeval to those observed in sequences in the Great Plains can be identified in Panama. Similarly to the upper part of the Arikaree Group (Hunt, 2004), late

Arikareean fluvial deposits are largely limited to shallow streams developed in the upper part of the Las Cascadas Formation (Montes et al., 2012; Rincón et al., 2012; Rincón et al., 2015). Moreover, the association of terrestrial mammals from the Lirio Norte L. F.

(ca. 21 Ma) is restricted to discrete and ephemeral fluvial intervals with abundant volcanic products and ash falls in the Lirio Norte area (YPA024). Although a more detailed sedimentological work is required to characterize this interval of tectonic activity in southern North America, the coeval sequences from the Great Plains are similar to the fluvial sequences of the upper part of the Las Cascadas Formation that represent the aggradation of volcanic valleys with no development of extensive and perennial

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fluvial systems. This interpretation is also supported by the scarcity of aquatic vertebrates in the fossiliferous localities from the upper part of the Las Cascadas

Formation. Riverine taxa (e.g. fishes) are almost absent in the main locality of the Lirio

Norte L. F. (YPA024) while fishes are well represented in the localities of the Centenario

Fauna. The ratio between the number of acthynoptherigian (fishes) specimens and mammalian terrestrial specimens is 0.003 in the Lirio Norte L. F. (YPA024) while reaching values near 0.5 in the main fossiliferous locality of the Centenario Fauna (data from https://www.flmnh.ufl.edu/vertpaleo-search/).

In contrast to the intense volcanic activity observed during the late Arikareean in western North America, the beginning of the Hemingfordian (more precisely the beginning of the Runningwater Chronofauna) in the Great Plains is characterized by drastic changes in sedimentation (MacFadden and Hunt, 1998). In Panama, this interval is characterized by the deposition of epiclastic sequences that, similar to those of the

Runningwater Formation in the Great Plains (Hunt, 2004), include a much greater proportion of sediment derived from the uplifts of an ancient volcanic topography. The source for these sediments includes mainly granitic plutons in the Great Plains (Hunt,

2004) while in Panama, these epiclastic sequences are the result of intense erosion and weathering of a volcanic peninsula that connected Panama and southern Mexico during the earliest Miocene (Rincón et al., 2012). Moreover, the ‘‘sudden’’ appearance of tropical coastal environments in Panama, represented in the upper Culebra and lower

Cucaracha Formations, is coeval with the rapid development of riparian environments in the Great Plains ca. 19 Ma (Hunt, 2004; MacFadden et al., 2014).

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Now that the chronostratigraphic context of the Panamanian fossil record has been improved by recently obtained radiometric dates (MacFadden et al., 2014; Bloch et al., 2016), to identify the paleobiogeographic processes responsible for the distinctiveness of the early Miocene Panamanian fossil mammals, the systematics, biostratigraphy, and paleobiogeography of three artiodactyl groups are discussed in detail. Selenodont mixed feeders represent the first group, the protoceratine

Paratoceras. A protoceratid genus with a unique tropical early Miocene distribution and, more remarkably, with an ancestry likely linked to the late Oligocene protoceratine

Protoceras that inhabited the Great Plains (Rincón et al., 2015). A second group includes the early Miocene floridatraguline camels, a group of selective browsers with an early Miocene tropical and subtropical distribution and, similarly to Paratoceras, with a temperate ancestry linked to late Arikareean Oxydactylus-like camelids. These camelids, although known from many early Miocene fossiliferous assemblages from higher latitudes, seem to be restricted to more open volcanic terrains of the western margin of southern North America during the late Arikareean only colonizing the Gulf

Coast and the Central Great Plains until the early Hemingfordian. The third group includes the more bunodont and more generalistic, early Miocene tayassuids from

Panama, an omnivorous ungulate group (represented in Panama by two new genera including three new species) that shows remarkable morphological changes in the dentition as well as in the cranial morphology once they colonized the tropical areas of the Panama Canal basin during the late Arikareean ca. 21 Ma.

This new systematic and geochronologic framework for the early Miocene ungulates of Panama has clear paleobiogeographic implications that allow for an

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assessment of the following questions: 1) Is the faunal turnover observed at the

Arikareean-Hemingfordian boundary at higher latitudes also present in the New World tropics?; 2) what do the relationships of early Miocene tropical artiodactyls to those of higher latitudes indicate regarding the origin and radiation of these mammals?; and 3) what role does the tropics play in the dynamics of intercontinental mammalian dispersals?

Early Miocene protoceratids from Panama.The early Miocene fossil record of

Panama includes three species of protoceratines, all classified in the genus

Paratoceras. The geographic distribution of species classified in the monophyletic

Paratoceras clade is consistent with the idea that the group as a whole was endemic to subtropical and tropical areas of the Gulf Coast, Mexico, and Panama and became an abundant component of ungulate faunas from southern Central America by the

Hemingfordian after colonizing recently emerged volcanic terrains connected to the Gulf

Coast during the Arikareean (Rincón et al., 2015). Although protoceratine fossils from the Lirio Norte L. F. were initially referred to Paratoceras aff. P. tedfordi based on the morphological characteristics of the upper dentition shared with early Miocene P. tedfordi from Mexico (Rincón et al., 2015), a recently discovered partial protoceratine skull from the Lirio area preserves dental and cranial morphologies that are only present in late Arikarrean Protoceras neatodelpha, a protoceratine protoceratid only known from

Niobrara County in Wyoming (Patton and Taylor, 1973; Rincón et al., 2015; manuscript in preparation).

After its arrival to tropical areas of southern North America, Paratoceras persisted in the tropical forests of Panama during the early Miocene (Hemingfordian NALMA),

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reaching the more temperate forest of Texas by the Barstovian NALMA (Patton and

Taylor, 1973; Rincón et al., 2015). By the late Miocene (Clarendonian NALMA),

Paratoceras macadamsi had evolved a more wedge-shaped p4, more reduced premolars, deeper mandible, and a more hypsodont dentition; these are all characteristics that are also found in synthetoceratine protoceratids (which are unknown south of Mexico; Webb, 2003). While it is certainly possible that these dental innovations (and inferred dietary specializations) are related to paleocological changes in the Gulf Coast during the late Miocene, testing this hypothesis would require detailed dietary, isotopic, and phytogeographic studies that are beyond the scope of this project.

The broad snout and brachydont dentitions of protoceratines (e.g. Paratoceras) are consistent with those of folivorous browsers with less-cursorial morphological traits such as short limbs, unfused metapodials, and four-toed manus. As such, protoceratines might have been restricted to more closed forest, and presumably more tropical habitats of southern Mexico and Panama (Prothero, 1998; MacFadden and

Higgins, 2004, Jaramillo et al., 2014) while the more hypsodont synthetoceratines likely inhabited more open habitats in the Gulf Coast during the Neogene (Webb et al., 2003).

The small protoceratid Paratoceras orarius is restricted to the lowermost stratigraphic levels of the Centenario Fauna and was found in sedimentary sequences believed to represent deltaic (delta front) and transitional environments (Upper Culebra Formation).

The medium sized P. coatesi is the most common ungulate recovered from the late

Centenario Fauna. These stratigraphic levels of the upper Cucaracha Formation may have represented more proximal deltaic plains (Kirby et al., 2008, Montes et al., 2012;

Rincón et al., 2015).

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While far from resolved given the paucity of data, morphological characters present in the male skull of P. coatesi (longer nasal bones and the gracile morphology of the supraorbital ossicones) are intermediate between those of late Arikareean

Protoceras neatodelpha and Barstovian Paratoceras wardi from Texas. In a temporal framework, this interpretation is consistent with an early Hemingfordian age for the

Centenario Fauna (Tedford et al., 2004; MacFadden, 2006; MacFadden et al., 2014;

Rincón et al., 2015).

Finally, Webb et al., (2003) suggested that Paratoceras tedfordi from Mexico is late Oligocene-early Miocene in age, but a younger proposed age (Vega et al., 2009;

Solórzano-Kraemer, 2007; 2010) could account for the similarities to aff. P. tedfordi from the late Arikareean Lirio Norte L. F. documented here. Finally, the new protoceratines from the Centenario Fauna (Paratoceras orarius and P. coatesi) share a distinctive p4 morphology (bulbous crown and relatively shorter) not present in either Barstovian P. wardi or Arikareean aff. P. tedfordi but present in the Clarendonian P. macadamsi.

While this conclusion is tentative, especially with the lower dentition of P. tedfordi still unknown, I suggest the possibility that allopatric speciation of Paratoceras in different paleobiogeographic provinces (e.g. tropical vs. subtropical) may have occurred in

Central America. However, the occurrence of Protoceras sp. (Rincón, manuscript in preparation) may allude to a new interpretation regarding the late Paleogene diversification of basal protoceratines.

The early Miocene floridatraguline camels from Panama. The late Arikareean

(~21 Ma) occurrence of the basal floridatraguline Floridatragulinae gen. et. sp. nov. in volcanic sequences from Panama highlights a remarkable paleobiogeographic pattern

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for early Miocene Oxydactylus-like camelids. Including the type of Oxydactylus longipes

(early Hemingfordian), late Arikareean oxydactylines are only reported from volcanic sequences along the western volcanic margin (active margin) of North America

(Woodburne et al., 1974; Whistler and Lander, 2003; Peterson, 1904). In contrast, oxydactylines are recorded in cratonic sequences from the Central Plains and the coastal plain of Texas only until the earliest Hemingfordian (Honey et al., 1998; Patton,

1969). This pattern, althought likely pervaded by taphonomic biases (erosion or no deposition) but not by sampling intensity, suggests that oxydactylines inhabited more open (volcanic) habitats during the late Arikareean NALMA, only colonizing habitats from the cratonic areas of the Central Great Plains and coastal plain sequences of the

Gulf Coast until the Hemingfordian NALMA.

This interpretation is further supported by the early Miocene paleobiogeography of the basal floridatragulines Floridatragulus and Aguascalientia. These two small camelids have biostratigraphic ranges that overlap (Rincón et al., 2012) but have never been reported from the same assemblage. Furthermore, these similarly sized floridatragulines (with elongate skulls and brachydont dentitions) likely inhabited similar niches along the same paleobiogeographic province. Nonetheless, the lithostratigraphic context of their occurrences confirms that each genus, instead, inhabited specific ecosystems. The relatively shorter-snouted Aguascalientia inhabited highly perturbed volcanic terrains (e.g the Chorotega Block in Panama (Lirio Norte L. F.) and tertiary volcanic rocks of Sierra Madre Occidental in Texas (Castolon L. F.), and the early

Hemingfordian sequences from the Tepehuano terrain (Zoyotal L. F.) in southern

Mexico (Dengo, 1985; Stevens, et al., 1977; Sedlock et al., 1993). In contrast, the

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relatively longer-snouted Floridatragulus inhabited karstic and coastal plain environments in the Gulf Coast and Panama during the Hemingfordian and Barstovian

NALMAs (Patton, 1969; White, 1940; Rincón et al., 2015) with no occurrence of this genus in any of the early Miocene volcanic sequences from the western margin of North

America. Furthermore, floridatragulines are not reported from any early late Arikareean assemblage in the Gulf Coast plain (e.g. Toledo Bend area) or any other late Arikareean assemblage in Florida (Rincón et al., 2012) where nothokematines were the dominant camelids. Consequently, allopatric speciation between nothikematines and oxydactylus- like camelids can be hypothesized during the early late Arikareean in the Gulf Coast as denoted by the occurrence of distinctive camelid taxa inhabiting each of these distinctive paleobiogeographic provinces. Floridatragulines, although present in the tropical and subtropical volcanic terrains of western North America during the late

Arikareean (Aguascalientia), are more commonly found as faunal elements in

Hemingfordian assemblages from the Gulf Coast. Conversely, nothokematines are common in late Arikareean assemblages from Florida while they have not been found in any coeval assemblages from the western area of the Gulf Coast.

Additional evidence of strong provincialism between peninsular Florida (including the eastern part of the Mississippi valley) is also preserved in middle to late Arikareean assemblages from the Gulf Coast. Similar to the late Arikareean Lirio Norte L. F., the early late Arikareean Toledo Bend and the Cedar Run faunas in Texas include ungulate genera reported in the Great Plains that are not known from any other assemblage in the Gulf Coast Plain (e.g. the anthracothere Arretotherium and parahippine horses)

(Albright, 1998). Although camelids are rare in these assemblages, the presence of

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riparian species (e.g. tapiroids, anthracotheres) suggests that the valley of the ancient

Mississippi River, in addition to being a corridor connecting the Gulf Coast with the

Central Plains, might have also operated as a barrier for ungulates during the middle

Arikareean. This orographic barrier only allowed the spreading of generalist artiodactyls like bunoselenodont entelodonts and bunodont peccaries similar to “Cynorca” (Albright,

1998; Tedford et al., 2004; O’Sullivan, 2003). The presence of middle Arikareean congeneric species of Dapheonodon and Nanotragulus in both the Gulf Coastal Plain and the Great Plains confirms that these two provinces were ecologically distinct

(Albright, 1998). Furthermore, this distinction may have begun only slightly earlier

(middle Arikareean) as denoted by endemic Gulf Coast forms in Florida

(nothokematines) and Texas (Gentilicamelus-like camelids), and oxydactyline camelids that led to late Arikareean tropical endemic taxa (e.g. floridatragulines) in southern

North America (Rincón et al., 2015).

Consequently, a Gentilicamelus-like camelid closely related to Nothokemas, colonized Florida during the early Arikareean. Although never formally described, the relationship of these camelids, only known from partial dentitions, have remained unclear since their original report in the Buda L. F. by Frailey (1979). By the late early

Arikareean the provincialism along southern North America intensified. Nothokematines thrived in Florida while Gentilicamelus-like camelids likely thrived in the subtropical volcanic terrains associated with the active margin in western North America (Texas) with no camelid occurrences in areas of the ancient Mississippi Valley (Albright, 1998).

By the late Arikareean, nothokematine camels became the most common camelids in

Florida, while oxydactylines (O. benedentatus), Gentilicamelus–like camelids

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(Priscocamelus, Delaxomeryx), and floridatragulines were also present in Texas

(Aguascalientia sp.) and Panama (Aguascalientia and Floridatragulinae gen. nov).

Surprisingly, stenomyline camels, the most common camelids elsewhere during the

Arikareean have not been reported from any of the late Arikareean assemblages from

Florida or Panama.

By the earliest Hemingfordian (c.a 19 Ma), provincialism weakened and floridatragulines were then well represented in the Gulf Coast (Miller Site L. F. and

Thomas Farm sites in Florida as well as the Garvin Gully L. F. in Texas), and Panama

(Centenario Fauna). By the late Miocene (Barstovian and Clarendonian NALMAs), ungulates with early Miocene origins in tropical areas of North America (e.g.

Floridatragulus) are present in the coastal plains habitats on the coastal plain of the passive margin of North America likely exploiting a northwardly expanding Neotropical woodland savanna environment (Albright, 1998).

The early Miocene tayassuids from Panama. Early Miocene tayassuids are represented in Panama by three hesperhyine genera: the bunodont Hesperhyinae n. gen. A & sp. A) and Hesperhyinae n. gen. B & sp. A, and the more lophodont

Floridachoerus sp. Hesperhyinae n. gen. A & sp. A from the late Arikareean Lirio Norte

L. F. is a small bunodont tayassuid that closely resembles the Arikareean

Marshochoerus socialis and defines the arrival of bunodont tayassuids to tropical areas of southern Central America during the late Arikareean NALMA (c.a. 21 Ma). The early

Hemingfordian Hesperhyinae n. gen. A & sp. B ( = “C”. occidentale MacFadden et al.,

2010) from the early Centenario Fauna (Upper Culebra Formation) although exhibiting distinctive tayassuine morphologies present in “C”. occidentale, lacks diagnostic dental

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and cranial tayassuine morphologies like the presence of a postprotoconal groove on

P4 and the reduction of the P1. Although the lack of upper premolars weakens the interpretations regarding its possible tayassuine affinities, the type of Hesperhyinae n. gen. B & sp. A preserves dental morphologies only present in the older and more bunoselenodont hesperhyines from higher latitudes. Consequently, the increase in relative size of the entoconulids observed in the early Miocene tayassuids from

Panama, similar to the changes in dental and cranial morphology observed in parahippine horses and floridatraguline camels, might have been a morphological adaptation for coping with new tropical forested habitats with food resources not existing in higher latitudes. Accordingly, late Arikareean populations of hysperhynes closely related to Marshochoerus (e.g. Hesperhyinae, gen. A) arrived to the marginal volcanic tropical terrains of Panama as partakers of the colonization of the recently formed peninsula connecting southern Mexico with the Panama Canal basin ca. 21 Ma. By the early Centenario Fauna (~ latest Arikareean), hesperhyines (Hesperhyinae n. gen. A & sp. B) had started to gain a more bunodont dentition by adding a series of conulids on lower molars (entoconulids) while retaining a pneumatic (plesiomorphic) maxillopalatine labyrinth in the skull. Although this interpretation is regarded as cautious given the lack of quantitative data and overall scarcity of tropical early Miocene tayassuid skulls, it suggests that early Miocene change in crown morphology could be a response to a shift in diet. In contrast to their more temperate counterparts, early Miocene Panamanian tayassuids, in fact, inhabited forested areas with a unique floral composition. The early

Miocene temperate floras present in the Gulf Coast and Mexico were dominated by temperate (Laurasia) taxa (Graham, 1995) while the early Miocene tropical forest from

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Panama, instead, is characterized by a tropical rain forest with tropical South American

(Gondwanan) phytogeographic affinities (Jaramillo et al., 2014). However, the occurrence of an early Arikareean bunodont tayassuid in southern Mexico (Ferrusquia-

Villafranca, 2003; Prothero et al., 2013) confirms that bunodont crowns (with reduced cristids on lower molars) are present in peccaries inhabiting transitional and coastal environments at least since the late Oligocene. Although the inclusion of the early

Arikareean Simojovelhyus in my phylogenetic analysis was not possible, it seems reasonable to hypothesize that this small tayassuid is more closely related to tayassuines than any coeval and more bunoselenodont species of Perchoerus (e.g.

Perchoerus probus). Once the taxonomic revision of basal late Oligocene tayassuids is achieved, the hypotheses regarding the tempo and mode of evolution of late Oligocene bunodont forms and the early Miocene tayassuines will be clarified.

Similarities in the dentition of the tayassuids from the early Centenario Fauna and coeval sequences from Delaware suggest that the tayassuid Hesperhyinae, gen. A was the only Panamanian ungulate able to rapidly colonize higher latitudes during the early

Hemingfordian. This distinctive pattern, not observed in any other artiodactyl from

Panama, can be explained by linking a continuous land connection with higher latitudesto food resources. For instance, palynological work carried out in the lower part of the Calvert Formation near the Pollack Farm area confirmed that the habitat was dominated by temperate or warm-temperate taxa, with low frequencies of exotic subtropical or tropical taxa similar to the floral composition of what is today the coastal region of Georgia and northern Florida. However, the relative abundance of tree and shrub pollen and the rarity of herbaceous pollen indicate closed habitats (dense forests)

233

developed in coastal (parallic) shallow marine to coastal environments (Groot, 1998).

Therefore, bunodont hesperhyine tayassuids similar to Hesperhyinae n. gen. A & sp. B were widely distributed along the transitional and coastal environments of North

America during the early Hemingfordian. Furthermore, this rapid colonization of habitats in higher latitudes was likely controlled by the distribution of transitional habitats (tidal flats and mangrove habitats) developed along coastal areas of North America. In a paleoclimatic perspective, this colonization was likely favored during warm intervals that followed the beginning of the Miocene and eventually led to the Mid-Miocene Climatic

Optimum ca. 15 Ma (Zachos et al., 2001; 2008). Although there is no geological evidence supporting the existence of paralic and transitional environments in the early

Miocene fossiliferous assemblages from Central Florida, this habitat preference would account for the absence of bunodont tayassuids in the intensively sampled localities developed in distinct karstic landscapes during the earliest Hemingfordian and their occurrence in shallow marine sequences in the western coast of Central Florida

(O’Sullivan, 2003). Unfortunately, the taxonomic resolution for many of the Arikareean isolated dentitions initially referred to “Cynorca” (now Marshochoerus) does not allow for clarification of the relationships between late Arikareean tayassuids from the Gulf Coast

(Frailey, 1969; Patton, 1969; Albright, 1999; O’Sullivan, 2003).

Early Miocene mammalian paleobiogeography. One of the most striking features of the Panamanian terrestrial fossil record is the late Arikareean (~21 Ma) occurrence of Hemingfordian Euro Asiatic immigrant groups in the Lirio Norte L. F., a distinct biogeographic pattern inferred for mammalian groups like procyonids and the sciurid Petauristodon (Rincón et al., 2014; Bloch et al., 2016). As such, the occurrences

234

of these mammalian taxa in Panama predate early Hemingfordian occurrences reported from temperate sequences in North America (MacFadden, 2006; Rincón et al., 2015;

Bloch et al., 2016). Consequently, the fossil evidence from Panama confirms that the earliest stages of faunal turnover observed in higher latitudes (i.e. the beginning of the

Runningwater Chronofauna) are preserved in early Miocene (21 to 19 Ma) tropical sequences from Panama. Furthermore, the occurrences of distinctive early

Hemingfordian immigrant mammalian taxa (a basal procyonid and the petauristine sciurid Petauristodon) in the late Arikareean assemblages from Panama, confirms that there is ~ 2 million years gap in the biological history of mammalian taxa (e.g. procyonids, chalicotheres, and the sciurid Petauristodon) likely preserved in the poorly sampled tropical areas of southern Central America. Independent of the different biases that might have influenced the preservation and eventual discovery of a late Arikareeam fossil record throughout North America, the Panamanian fossil record clearly characterizes the diversification (cladogenesis) of mammalian groups that followed the colonization of tropical forested areas of southern North America during the late

Arikareean. Consequently, the resulting early Hemingfordian tropical endemic groups

(e.g. Paratoceras, Aguascalientia, Floridatragulus) likely diversified in response to inhabiting a novel tropical biome with a distinctive floral composition therefore evidencing an adaptive radiation of selenodont artiodactyls.

While some ungulate clades (e.g. the protoceratines, the floridatraguline camels, and the anthracotheres) show taxonomic affinities to subtropical taxa from the Gulf

Coast and southern Mexico (Rincón et al., 2012a; Rincón et al., 2013); other ungulates such as equids, oreodonts, moschids, rhinoceroses, and the amphicyonine carnivores

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expanded their latitudinal distribution from the late Oligocene, spreading in the early

Miocene from the Holarctic temperate sequences to the tropical areas of Panama

(MacFadden, 2009; Rincón et al., 2012b; MacFadden et al., 2014). Although an early

Miocene migration of herpetofauna between the Americas has been proposed (Cadena et al., 2012; Head et al., 2012; Hastings et al., 2013), the early Miocene (late

Arikareean) platyrrhine primate Panamacabus from the Lirio Norte L. F. in Panama is the only evidence of an earlier phase of interchange between South and North America

(Bloch et al., 2016).

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Figure 5-1. Rarefaction Curves calculated for individual localities (YPAs) along the Panama Canal area. Y-axis represents the number of ungulate species identified based on different tooth positions (see Appendix K). Curves generated using PAST 3.0.1 (Hammer et al., 2011).

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Figure 5-2. Rarefaction Curves calculated after integrating ungulate fossils from the late Arikareean Lirio Norte L. F. and the early Hemingfordian Centenario Fauna. Y-axis represents the number of species identified based on different tooth positions (see Appendix L). Curves generated using PAST 3.0.1 (Hammer et al., 2011).

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Table 5-1. Minimum Number of individuals (MNI) calculated based on the occurrence of ungulate tooth positions in early Miocene sequences from Panama. Abbreviations: A, Aguascalientia; CF, Centenario Fauna; CucFm, Cucaracha Fm.; Cul, Culebra Fm.; Lcf, Las Cascadas Fm.; LNF, Lirio Norte Local Fauna; P, Paratoceras.

(LNLF)

p. nov.p. B

Site Key Formation Fauna Arretotherium sp. Protoceras sp. sp.Parat coatesiP. orariusP. Floridatragulinae Gen. sp.nov.et. panamaensisA. minutaA. Floridatragulus Calichotheriidae Parahippine Anchitherium Archaeohippus sp. Hesperhyinae gen.n. sp. & A B Hesperhyinae gen.n. sp. & B A Hesperhyinae, gen.B. et. s Floridachoerus sp. Moschidae sedisinc Entelodontidae Merychoidodontinae 1 Merychoidodontinae 2 Rhinoceratidae MNI perkey site % total 002 Cuc. CF 0 0 0 2 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 1 0 1 6 4.7 003 Cuc. CF 0 0 0 2 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 3 2.4 005 Cuc. CF 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 2 1.6 008 Cuc. CF 0 0 0 1 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 3 2.4 009 Cuc. CF 0 0 0 2 0 0 0 0 1 0 0 1 0 0 0 0 1 1 0 0 0 2 8 6.3 011 Cuc. CF 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 2 1.6 012 Cuc. CF 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0.8 015 Cul. CF 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0.8 016 Cul. CF 0 0 0 0 1 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 3.1 019 Cuc. CF 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 2 1.6 026 Cuc. CF 0 0 0 3 0 0 0 0 4 0 0 1 4 0 0 0 0 2 0 0 0 0 14 11.0 027 Cuc. CF 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0.8 037 Cuc. CF 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0.8

239

Table 5-1. Continued

& sp.& A

nae gen.n. B sp.& A

Site Key (YPA) Formation Fauna Arretotherium sp. Protoceras sp. sp.Parat (LNLF) coatesiP. orariusP. Floridatragulinae Gen. et. sp.nov. panamaensisA. minutaA. Floridatragulus Calichotheriidae Parahippine Anchitherium Archaeohippus sp. Hesperhyinae gen.n. A sp.& B Hesperhyi Hesperhyinae gen.n. Floridachoerus sp. Moschidae sedisinc Entelodontidae Merychoidodontinae 1 Merychoidodontinae 2 Rhinoceratidae % total

050 Cuc. CF 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 3 2.4 060 Cuc. CF 0 0 0 3 0 0 0 0 0 0 0 1 1 0 0 0 0 2 1 1 0 2 11 8.7 063 Cul. CF 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0.8 071 Cuc. CF 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 2 1.6 072 Cuc. CF 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 2 1.6 073 Cuc. CF 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1.6 079 Cuc. CF 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0.8 081 Cuc. CF 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0.8 084 Cul. CF 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0.8 086 Cuc. CF 0 0 0 2 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 1 5 3.9 LNL 080 Lcf. F 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0.8 LNL 036 Lcf. F 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 2 1.6 LNL 024 Lcf. F 2 1 2 0 0 4 13 0 0 1 15 0 0 0 0 3 0 5 0 0 0 1 47 37.0

Total 2 1 2 19 4 4 14 1 7 1 15 5 10 3 5 3 2 12 3 3 1 10 127 100

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Table 5-1. Continued

nchitherium

Fauna Arretotherium sp. Protoceras sp. sp.Parat (LNLF) coatesiP. orariusP. Floridatragulinae gen. sp.et. nov. panamaensisA. minutaA. Floridatragulus Calichotheriidae Parahippine A Archaeohippus sp. Hesperhyinae gen.n. A sp.& B Hesperhyinae gen.n. B sp.& A Hesperhyinae gen.n. A sp.& B Floridachoerus sp. Moschidae sedisinc Entelodontidae Merychoidodontinae 1 Merychoidodontinae 2 Rhinoceratidae % total %CF 0 0 0 25 5 0 0 0 9 0 0 6 13 4 6 0 3 9 3 4 1 12 100 %LN F 4 2 4 0 0 8 28 2 0 2 30 0 0 0 0 6 0 10 2 0 0 2 100 % Total 2 1 2 15 3 3 11 1 5 1 12 4 8 2 4 2 2 9 2 2 1 8 100

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Table 5-2. Alpha diversity indexes calculated using PAST 3.0.1 for the early Miocene ungulates from the Panama Canal Area. Abbreviations: CF, Centenario Fauna; LNLF, Lirio Norte Local Fauna. Biodiversity parameters were calculated using Past3.0.

LNLF Lower Upper CF Lower Upper Taxa_S 12 11 12 13 13 13 Individuals 50 50 50 77 77 77 Dominance_D 0.1936 0.14 0.2528 0.1236 0.1041 0.1736 Simpson_1-D 0.8064 0.7472 0.86 0.8764 0.8261 0.8959 Shannon_H 1.967 1.753 2.176 2.305 2.101 2.39 Evenness_e^H/S 0.596 0.5137 0.7535 0.7711 0.6288 0.8394 Brillouin 1.685 1.501 1.874 2.059 1.871 2.138 Menhinick 1.697 1.556 1.697 1.481 1.481 1.481 Margalef 2.812 2.556 2.812 2.763 2.763 2.763 Equitability_J 0.7918 0.7267 0.8843 0.8986 0.8191 0.9318 Fisher_alpha 5.007 4.359 5.007 4.482 4.482 4.482 Berger-Parker 0.3 0.24 0.42 0.2468 0.1688 0.3506 Chao-1 15.33 11 26 13 13 16

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CHAPTER 6 CONCLUSIONS

From a biostratigraphic perspective, there is no obvious discrepancy between the inferred ages based on the grade of evolution of artiodactyl taxa from Panama and the radiometric dates reported by MacFadden et al., (2015) for the Centenario fauna, and

Bloch et al., (2016) for the Lirio Norte L. F. The distinctive biostratigraphic and paleobiogeographic patterns of the most common artiodactyls in Panama

(floridatraguline camels and protoceratids) confirms the presence of a distinctive early

Miocene faunal province connected with the Gulf Coast with no occurrence of these tropical genera in any coeval sequences from the central Great Plains (Rincón et al.,

2012; Rincón et al., 2015).

My results support that morphological change (cladogenesis) was associated to the colonization of these recently formed tropical biomes and was also manifest in some artiodactyl groups (floridatragulines and hesperhyine tayassuids) that underwent an adaptive radiation as they colonized tropical habitats of southern North America.

Moreover, the subsequent changes in diet are indeed responsible for the modifications in the dentition (bunodonty) and skulls (elongation of the snout) observed in taxa present in the Hemingfordian taxa from Panama. This rapid tropical diversification of artiodactyls with a temperate followed a rapid transition from more open temperate habitats to novel and more densely vegetated tropical habitats during the early

Neogene. As such, floridatraguline ancestry is linked to an Oxydactylus-like camelid that colonized the tropics during the early late Arikareean. The spreading of mammalian communities into tropical latitudes might be linked to the magmatic activity that resumed in southern North America ca. 25 Ma just after the break up of the Farallones plate

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(Mann et al., 2007; Farris et al., 2011). By the late Arikareean and early Hemingfordian

NALMAs (ca. 21-19 Ma), descendants of this Oxydactylus-like camelid were already represented by three floridatraguline genera in Panama: Floridatragulinae gen. et. sp. nov., Floridatragulus and Aguascalientia. The occurrence of Aguascalientia and

Floridatragulinae gen. et. sp. nov. in the Lirio Norte L. F in Panama suggests that

Aguascalientia is the product of sympatric speciation of camelids similar to

Floridatragulinae gen. et. sp. nov. that became progressively isolated from the Great

Plains during the late Oligocene periods of intense magmatism along the Central

American Volcanic arc (Farris et al., 2011). These tropical areas of Panama represented a novel niche for ungulates that favored cladogenesis by offering novel food resources while also limiting the dispersal capability of highly specialized allochthonous herbivores (e.g. South American platyrrhine monkeys) to higher latitudes

(Bloch et al., 2016).

The early Miocene mammalian disparity observed in southern North America was extreme during the Late Arikareean NALMA as denoted by strong provincialism between the coastal plain sequences of the Gulf Coast and the volcanic sequences from southwestern North America (Panama and Texas). In contrast, the beginning of the Hemingfordian NALMA is characterized by a weakened provincialism that favored the rapid dispersal northwards of late Arikareean tropical endemic taxa. This dispersal of the rapidly developing tropical taxa might have only been permitted when the

Neotropical woodland savanna environments allowed access to the Gulf region soon after the earliest Hemingfordian NALMA (Albright, 1998). Therefore, the colonization of low land environments along the passive margin of North America (Gulf Coast) during

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the Hemingfordian was only achieved until ungulates with a more temperate ancestry gained important morphological adaptations (e.g. elongation of the rostrum, more bunodont dentition, a relatively long and narrow fused symphysis) to exploit the novel and denser forested habitats developed in southern North America and the Gulf Coast.

Although the appearance of modern clades (e.g. equine perissodactyls, camelines and tayassuines) in North America is recorded during the late early to middle Miocene

(Hulbert and MacFadden, 1991; Honey et al., 1998; Wright, 1998), the effects of tectonism and volcanism on the evolution of modern and extinct clades (e.g. protoceratines, camelines, tayassuines) are evident. Although previously not considered in the origins of modern lineages of camels, the results of my phylogenetic analysis suggest that floridatragulines are more closely related to Oxydactylus (Peterson, 1904) than to any other early Miocene camelid with entostylids on lower molars. More importantly, my topology suggests that basal camelines are also a byproduct of this late

Arikareean camelid radiation. Furthermore, the early evolution of these clades is linked to a combination of changes in habitat structure and more complex abiotic processes

(e.g. changes in pCO2, relatively low eustatic sea level) that drastically modified early

Miocene North American ecosystems. Despite if it was this event that resulted in the dwindling and eventual extinction of the late early Miocene Gulf Coast browsing fauna and its replacement by more hypsodont mixed feeder herbivores, a late early Miocene

(Barstovian NALMA) continuity between northern (Great Plains) and southern faunas in the Gulf Coast is evident (Albright, 1998).

Two main diversification phases of camelids are identified based on the phylogenetic results and the geographic occurrence of tropical and subtropical camelids

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near the Oligocene-Miocene transition. The first one is represented by the diversification of Gentilicamelus-like camelids (nothokematines and likely the small camelid from the

Buda L. F.) during the early to middle Arikareean. This event can be correlated to glacioeustatic low sea levels Mi-1 of Lear et al., (2013). A second event near the

Arikareean-Hemingfordian boundary roughly corresponds to the beginning of the

Runningwater Chronofauna identified in the Great Plains (Webb and Opdyke, 1996).

This turnover event is likely associated to a second Neogene change in the glacioeustatic sea level, the Mi-1b and is recorded at the beginning of the Centenario

Fauna, more specifically by progradation of deltaic systems in the upper part of the

Culebra Formation. This lithostratigraphic sequence, evidencing a distinct change in the tectonic setting of southern North America, is coeval with the beginning of the

Hemingfordian NALMA in higher latitudes (MacFadden et al., 2014). Additionally, the radiometric dates reported by Montes et al, 2012 and MacFadden et al., 2014 suggest that sediments representing the Centenario Fauna were deposited rapidly in a complex tectonic scenario characterized by normal faulting and an increase in the relative sea level that allowed the deposition of shallow marine and prodelta sequences in the

Gaillard Cut area. Despite the fact that the Centenario Fauna represents a geographically restricted fossil association, I found no evidence supporting that this natural assemblage of interacting animal populations maintained its basic structure over a geologically significant interval of time. Nonetheless, it seems clear that both assemblages, although comparable in species richness, represent communities inhabiting distinctive ecosystems.

246

From a paleoecological perspective, the early Miocene mammalian communities from Panama include exclusively brachydont ungulates with no evidence of hypsodont forms. However, the new basal floridatraguline genus (Floridatragulinae gen. et. sp. nov.) and the parahippine horse from the Lirio Norte L. F. (Rincón et al. 2015) exhibit an increase in the crown height. This relatively early occurrence of mesodont crowns in ungulates from Panama (21 Ma), otherwise only recorded in early Hemingfordian ungulates, suggests that hypsodonty originated as a response to an increase in dietary abrasion caused by volcanic ash (Strömberg, 2013) and not a change in diet (i.e., grazing).

The early Miocene tayassuids from Panama experienced a similar early Miocene diversification process with concomitant changes in dental and cranial morphologies

Identified in floridatraguline camelids and protoceratids. The morphological change is consistent with an early Miocene adaptative radiation that continued during the late early Miocene finally leading to the appearance of tayassuines in the Barstovian

NALMA. However, if the presence of a compartmentalized maxillopallatine labarythm in early Hemingfordian Hesperhyinae n. gen. A & sp. B. from the early Centenario Fauna is confirmed, a definition of an expanded Tayassuinae clade will be required to include the new early Hemingfordian genera from Panama.

The early Hemingfordian occurrence of a hesperhyine tayassuid similar to

Hesperhyinae, gen. A. in temperate areas of Maryland and the Chesapeake Bay suggests that bunodont tayassuids remained restricted to transitional and paralic sequences in southern North America during the early Miocene (Wright and Eshelman,

1987; Albright, 1999; O’Sullivan, 2003). Furthermore, this interpretation accounts for the

247

rarity of early Hemingfordian bunodont tayassuids in more proximal sequences (Upper e.g. Cucaracha Formation), and in the karstic environments in central Florida (e.g.

Thomas Farm site).

These distinct paleobiogeographic patterns suggest that the early Miocene colonization of southern Central America by mammalian taxa with temperate affinities occurred by biotic corridors (highly perturbed volcanic sequences developed in the western active margin of the North American Plate). These more xeric habitats, with sporadic fluvial systems were somehow more similar to those inferred in the Great

Plains than to the more vegetated (riparian) habitats present in the Gulf Coast during the beginning of the late Arikareean (e.g. Toledo Bend L. F.). Although it is possible that the differences in the faunal composition of the Lirio Norte L. F. and the Centenario

Fauna are due to remarkable differences in the depositional paleoenvironment, the small floridatragulines Aguascalientia and Floridatragulus are never found in the same assemblage from southern North America. Aguascalientia is more common in volcanic

(xeritic) environments (e.g. Delaho Formation, Las Cascadas Formation), while basal floridatragulines are only reported from the wetter (mesic to hydric), more closed habitats in the Texas Gulf Coast and Panama.In other words, these selenodont ungulates were not ready to colonize the wetter environments of the Gulf Coast until the early Hemingfordian.The subsequent colonization of more mesic tropical habitats was possible only after the acquisition of the distinctive cranial and dental morphologies required to inhabiting the more closed habitats present in southern North America.

Consequently, endemic tropical mammalian gropus with temperate ancestry

(floridatraguline camels, protoceratine protoceratids) colonized tropical areas first

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(during the late Arikareean) by using biotic corridors restricted to this volcanic western margin of the North American plate (a distinctive ecosystem not present in the Gulf

Coast). This colonization was followed by a rapid diversification of ungulates (an adaptive radiation for floridatraguline and protoceratines) during the latest Arikareean- earliest Hemingfordian. These new early Hemingfordian artiodactyls with a tropical late

Arikareean ancestrycolonized more temperate areas of the Gulf Coast and Florida during the late early Miocene coinciding with the expansion of woodland savanna environment in the Gulf Coast (Albright, 1998). Although this paleobiogeographic pattern is consistent with the New World Tropics as a cradle of biodiversity during the early Miocene (eg. Paratoceras, Aguascalientia and Floridatragulus), the occurrence in

Panama of ungulate groups with a temperate ancestry (equids, chalicotheres, rhinoceroses, and oreodonts) confirms that some ungulate groups expanded their latitudinal distribution from the late Oligocene, spreading in the early Miocene tropical areas of Panama (MacFadden, 2009; Rincón et al., 2012b; MacFadden et al., 2014;

Rincón et al., 2013).

My interpretations suggest a link between changes in habitat structure and the appearance of novel dental and cranial morphologies; however, it seems clear that the northward spreading of early Miocene ungulate tropical taxa was controlled by the distribution of distinctive habitats, e.g. woodland savannas and tropical forested areas.

Consequently, primary browsers, either selective browsers (floridatragulines) or mixed feeders (protoceratines), remained restricted to the tropical areas of North America until remarkable phytogeographic processes led to the appearance of similar habitats in the

Gulf Coast (Albright, 1998; Rincón et al., 2015). Finally, the appearance of modern

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ungulate groups (Equinae, Tayassuinea, Camelinae) during the late Hemingfordian and early Barstovian NALMAs in the fossil record from higher latitudes seems to be linked to the intense phytogeographic changes in southern North America (spreading of a woodland savanna) that shaped the faunal composition in subtropical late Miocene assemblages (Albright, 1998). The early Neogene diversification of ungulate groups in tropical volcanic areas led to the appearance of endemic grups like floridatraguline camelids and protoceratines with distinct dental and cranial morphologies. However, these ungulate groups were not able to exploit the northwardly expanding Neotropical woodland savanna environments and became extinct during the late Miocene as response to overall cooler and drier conditions (Zachos et al., 2001; Zachos et al.,

2008). Ongoing paleontological work, as well as new paleogeographic interpretations

(Farris et al., 2011; Montes et al., 2012; Coates and Stallard, 2013), offer a new model to further explore the diversification processes that might have affected terrestrial vertebrates that colonized the volcanic terrains that emerged during the late Oligocene and early Miocene in the southern part of North America.

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APPENDIX A DENTAL MEASUREMENTS OF PROTOCERATINES FROM THE EARLY MIOCENE FROM PANAMA

Table A-1. Dental measurements of Paratoceras from the early Miocene of Panama. Abbreviations: APL, anterior-posterior length. TWmx: maximum transverse width. TWHyd: transverse hypoconulid width. *: highly deformed fossils excluded from the statistical summary. UF

Taxon Catalog Tooth position APL (mm) TWmx (mm) TWHyd (mm)

number

P. coatesi UF 271182 Rp1 6.36 3.55 -

P. coatesi UF 271623 Lp1 6.26 3.62 -

P. coatesi UF 271181 Rp2 13.74 6.10 -

P. coatesi UF 267123* Lp2 14.31 5.76 -

P. coatesi UF 271182 Rp3 13.99 6.29 -

P. coatesi UF 271624* Rp3 15.50 6.03 -

P. coatesi UF 223328* Rp3 12.30 5.25 -

P. coatesi UF 271181 Rp3 13.48 6.45 -

P. coatesi UF 280222 Rp3 12.47 6.17 -

P. coatesi UF 271623 Lp3 13.36 6.31 -

P. coatesi UF 267123* Lp3 16.27 7.43 -

P. coatesi UF 271182 Rp4 10.76 7.43 -

P. coatesi UF 271624* Rp4 11.67 7.45 -

P. coatesi UF 223328* Rp4 9.90 6.50 -

P. coatesi UF 271181 Rp4 10.67 7.93 -

P. coatesi UF 280222 Rp4 8.95 7.34 -

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Table A-1. Continued UF

Taxon Catalog Tooth position APL (mm) TWmx (mm) TWHyd (mm)

number

P. coatesi UF 223094 Lp4 9.96 7.56 -

P. coatesi UF 271623 Lp4 10.56 7.76 -

P. coatesi UF 267124* Lp4 11.17 8.14 -

P. coatesi UF 267123* Lp4 13.68 9.63 -

P. coatesi UF 267125 Lp4 10.66 7.72 -

P. coatesi UF 280222 Rm1 11.66 10.60 -

P. coatesi UF 271182 Rm1 11.90 10.96 -

P. coatesi UF 271624* Rm1 14.13 10.50 -

P. coatesi UF 223328* Rm1 10.26 8.81 -

P. coatesi UF 271181 Rm1 12.01 11.69 -

P. coatesi UF 271623 Lm1 11.55 9.66 -

P. coatesi UF 237854 Lm1 11.85 9.90 -

P. coatesi UF 223094 Lm1 12.21 10.61 -

P. coatesi UF 267124* Lm1 12.29 11.47 -

P. coatesi UF 267123* Lm1 12.66 12.39 -

P. coatesi UF 236927 Lm1 11.66 10.01 -

P. coatesi UF 280222 Rm2 12.36 12.02 -

P. coatesi UF 271182 Rm2 13.18 11.73 -

P. coatesi UF 271624* Rm2 16.35 11.93 -

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Table A-1. Continued UF Taxon Tooth position APL (mm) TWmx (mm) TWHyd (mm) Catalog number

P. coatesi UF 271181 Rm2 13.22 13.39 -

P. coatesi UF 223328* Rm2 12.77 9.92 -

P. coatesi UF 271623 Lm2 13.15 11.80 -

P. coatesi UF 237854 Lm2 13.71 12.63 -

P. coatesi UF 223094 Lm2 14.54 12.72 -

P. coatesi UF 267124* Lm2 12.43 12.98 -

P. coatesi UF 267123* Lm2 14.33 12.50 -

P. coatesi UF 271182 Rm3 17.98 11.52 6.89-

P. coatesi UF 271624* Rm3 19.22 12.53 6.77

P. coatesi UF 223328* Rm3 19.70 9.90 6.84

P. coatesi UF 271596 Rm3 17.99 11.23 6.53

P. coatesi UF 271623 Lm3 18.12 10.95 6.91

P. coatesi UF 237854 Lm3 20.62 11.82 7.01

P. coatesi UF 223094 Lm3 17.92 12.72 7.15

P. coatesi UF 267124* Lm3 16.18 12.67 6.70

P. coatesi UF 267123* Lm3 21.75 13.01 6.90

P. coatesi UF 271150 Lm3 17.38 12.03 7.10

P. orarius UF 237878 Lm1 9.25 7.18 -

P. orarius UF 237878 Lm2 10.42 8.01 -

253

Table A-1. Continued UF Taxon Tooth position APL (mm) TWmx (mm) TWHyd (mm) Catalog number

P. orarius UF 237878 Lm3 13.95 8.18 4.98

P. orarius UF 271625 Rp3 10.73 4.27 -

P. orarius UF 271625 Rp4 8.45 5.37 -

P. orarius UF 271625 Rm1 9.42 7.61 -

P. orarius UF 271625 Rm2 10.05 8.40 -

P. orarius UF 271625 Rm3 15.36 8.43 -

P. orarius UF 280222 Rm2 9.84 7.62 -

P. orarius UF 280223 Lm2 9.70 7.84 -

P. aff. tedfordi UF 254121 Lm2 12.97 10.20 -

P. aff. tedfordi UF 271179 Lm2 13.51 10.32 -

P. aff. tedfordi UF 254119 Rp4 10.54 6.50 -

P. aff. tedfordi UF 271622 Lm2 14.60 10.66 -

P. aff. tedfordi UF 271627 Rm2 13.88 10.77 -

P. aff. tedfordi UF 267194 Rp4 11.60 7.01 -

P. aff. tedfordi UF 267194 Rm1 10.55 9.24 -

P. aff. tedfordi UF 267194 Rm2 12.12 11.27 -

P. aff. tedfordi UF 267194 Rm3 18.12 10.67 6.85

P. aff. tedfordi UF 275168 Lm2 13.84 10.11 -

P. aff. tedfordi UF 275168 Lm3 21.08 10.40 6.56-

254

Table A-1. Continued UF Taxon Tooth position APL (mm) TWmx (mm) TWHyd (mm) Catalog number

P. aff. tedfordi UF 241199 LP2 12.22 8.70 -

P. aff. tedfordi UF 271626 RP3 10.41 5.97 -

P. aff. tedfordi UF 236931 LM2 13.03 16.68 -

P. aff. tedfordi UF 271618 RP4 8.78 11.01 -

P. coatesi UF 237877 RP2 12.63 6.18 -

P. coatesi UF 237877 RP3 12.65 8.58 -

P. coatesi UF 223584 LP3 11.79 8.46 -

P. coatesi UF 236913 RP4 8.22 13.47 -

P. coatesi UF 237877 RP4 9.41 12.30 -

P. coatesi UF 223585 RP4 8.83 13.83 -

P. coatesi UF 223584 LP4 7.79 11.53 -

P. coatesi UF 236913 RM1 11.06 14.48 -

P. coatesi UF 223585 RM1 10.81 14.80 -

P. coatesi UF 237862 LM1 11.29 14.34 -

P. coatesi UF 223326 LM1 11.37 15.73 -

P. coatesi UF 223584 LM1 10.99 13.49 -

P. coatesi UF 223585 LM1 11.04 15.03 -

255

Table A-1. Continued UF Taxon Tooth position APL (mm) TWmx (mm) TWHyd (mm) Catalog number

P. coatesi UF 237877 RM2 12.83 16.44 -

P. coatesi UF 223585 RM2 12.92 17.77 -

P. coatesi UF 223326 LM2 11.92 17.16 -

P. coatesi UF 223585 LM2 12.82 17.94 -

P. coatesi UF 236917 RM3 13.36 17.65 -

P. coatesi UF 237877 RM3 11.79 16.08 -

P. coatesi UF 223585 RM3 12.26 17.21 -

P. coatesi UF 223326 LM3 11.63 16.18 -

P. coatesi UF 280221 RM3 13.58 16.18 -

P. coatesi UF 223585 LM3 12.43 16.91 -

P. coatesi UF 275284 RM3 13.30 17.80 -

]

256

APPENDIX B DENTAL CHARACTERS USED IN THE PHYLOGENETIC ANALYSIS OF PROTOCERATINAE (CHAPTER 2). ALL CHARACTERS ARE TREATED AS UNORDERED.

1) Anterior end of nasal bones: anterior to P3 (0); posterior to P3 (1).

2) Upper molars: square, brachydont with thick enamel APL/TW ratio > 0.8 (0); brachydont, wider than longer APL/TW ratio <0.8, thick enamel (1).

3) Protocone on upper P3: strongly developed conforming an internal cusp lingual to the paracone (0); reduced and restricted to the basal part of the crown (1); reduced to basal cingular segments interrupted by an inflate paracone (2); absent (3).

4) Cinguli on upper molars: discontinuous, strong and tall conforming a shelf between protocone and metaconule (0); strong and restricted to the anterior part of the protocone and metaconule (1); strong and basal but continuous (2).

5) Horizontal lateral ridge extending from the outer face of the maxillary bone to the orbit: weak or absent (0); strong and continuous (1); strong and discontinuos (2)

6) Anterior end of the orbits: posterior to M3 (0); anterior to M3 (1).

7) Protoconid on p4: strong with a tall metaconid running lingually, entoconid weak and low (0); reduced conforming an open valley with the hypoconid, no entoconid (1); reduced but conforming a narrow valley with the hypoconulid (2).

8) p4 morphology: APL/TW ratio: elongated; ratio > 1.6 (0); shortened ratio < 1.6 (1)2

9) Parastylid on lower molars: strong (0); weak or absent (1).

10) APL m1/p4: < 1.0 (0); > 1.0 (1).

11) Strong protocone on P2: present (0); absent (1).

257

12) Morphology of the labial margin of P3: labially concave (0); straight with reduced parastyle (1)

13) p4 talonid morphology: elongated, entoconid entostilid sligtly divergent, deep fossetid (0); reduced, entoconid entostilid divergent, deep fossetid (1); anterioposteriorly reduced conforming a wedge-shaped tooth with a bulbous talonid and shallow fossetid

(2)

14) p3 hypoconid reaching the protoconid (0); p3 hypoconid reaching the metaconid: (1)

15) paraconid on p3: absent (0); present and lingually inflected (1); enlarged or bulbous

(2).

Abbreviations: APL, Anterior-Posterior Length

258

APPENDIX C CHARACTER-TAXON MATRIX USED IN PHYLOGENETIC ANALYSES OF PROTOCERATIDAE (CHAPTER 2). SEE APPENDIX B FOR CHARACTER DESCRIPTIONS

1 1

1234567890 12345

Heteromeryx dispar 001000001? 000?0

Pseudoprotoceras longinaris 0012?000?? 10???

Pseudoprotoceras taylori 0030000??? 11???

Protoceras neatodelpha ?0111?1??? 10?0?

Protoceras celer 0001101010 00101

Paratoceras tedfordi 1022?1???? ?1???

Paratoceras aff. tedfordi ?122??1000 111??

Paratoceras orarius ??????2111 ?1211

Paratoceras wardi 1122112101 11111

Paratoceras macadamsi ??2???2111 11212

Paratoceras coatesi 1122112111 11211

259

APPENDIX D DENTAL MEASUREMENTS OF EARLY MIOCENE CAMELIDS FROM SUBTROPICAL AND TROPICAL ASSEMBLAGES FROM NORTH AMERICA.

Table D-1. Dental measurements (upper dentition) of early Miocene camelids from Southern North America. Abbreviations: BAPL, basal anterior-posterior length. BTWmx: basal maximum transverse width. BTWHyd, basal transverse hypoconulid width. Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 183807 Camelidae Thomas Farm R DP2 11.85 5.46 UF 246853 Floridatragulus sp. Cucaracha R DP3 9.75 n/a 6.53 UF 183304 Camelidae Thomas Farm R DP3 14.5 9.15 UF 216633 Camelidae Thomas Farm R DP3 13.89 8.34 UF 183807 Camelidae Thomas Farm R DP3 15.45 10.72 UF 201767 Camelidae Thomas Farm L DP3 14.21 9.16 UF 246853 Floridatragulus sp. Cucaracha R DP4 8.17 8.18 8.32 UF 216245 Camelidae Thomas Farm L DP4 11.71 10.75 11.05 UF/FGS 6500 Camelidae Thomas Farm L DP4 14.7 10.98 11.25 UF 183807 Camelidae Thomas Farm R DP4 14.03 12.12 13.23 UF 187560 Camelidae Thomas Farm L DP4 13.78 11.37 12.12 UF 248818 Floridatragulus sp. Thomas Farm L DP4 10.03 10.38 11.13 UF 5313 Floridatragulus sp. Thomas Farm L DP4 12.5 10.8 11.2 UF 280149 Aguascalientia sp. Las Cascadas R DP4 10.81 7.93 UF 281478 Aguascalientia Las Cascadas R P1 6.6 panamaensis UF 275169 Aguascalientia sp. Las Cascadas L P1 6.6 UF 280574 Aguascalientia sp. Las Cascadas L P1 6.25 UF 280628 Aguascalientia sp. Las Cascadas R P1 6.79 UF 280745 Aguascalientia sp. Las Cascadas L P1 6.75 UF 275483 Floridatragulinae n. gen & Las Cascadas L P1 7.46 sp. CAST Floridatragulus Thomas Farm R P2 11.36 3.09 dolichanthereus UF 183302 Floridatragulus sp. Thomas Farm L P2 10.86 4.03 UF 189991 Floridatragulus sp. Thomas Farm L P2 11 4.15

260

Table D-1. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 196836 Floridatragulus sp. Thomas Farm R P2 10.45 4.78 UF 211312 Floridatragulus sp. Thomas Farm L P2 10.33 4.84 UF 273894 Floridatragulus sp. Thomas Farm R P2 10.52 3.37 UF 173050 Floridatragulus sp. Thomas Farm L P2 11.3 4.25 UF 206018 Nothokemas floridanus Thomas Farm R P2 11.17 4.98 UF 289251 (MCZ 4322 Nothokemas floridanus Thomas Farm R P2 10.98 5.31 Cast) UF 289275 Nothokemas floridanus Thomas Farm R P2 11.91 5.89 UF 190400 Nothokemas sp. Thomas Farm R P2 11.11 4.97 UF 214877 Nothokemas sp. Thomas Farm R P2 10.01 3.99 UF 269736 Nothokemas sp. Thomas Farm L P2 9.63 4.03 UF 315408 Nothokemas sp. Thomas Farm L P2 11.86 5.12 UF 273890 Nothokemas sp. Thomas Farm L P2 11.27 5.28 UF 273889 Nothokemas sp. Thomas Farm L P2 12.1 5.15 UF 183415 Nothokemas sp. Thomas Farm L P2 11.26 5.03 UF 181807 Nothokemas sp. Thomas Farm L P2 12 5.1 UF 281478 Aguascalientia Las Cascadas R P2 11.08 5 panamaensis UF 281478 Aguascalientia Las Cascadas L P2 10.9 5.03 panamaensis UF 267047 Aguascalientia sp. Las Cascadas L P2 11.33 5.23 UF 275169 Aguascalientia sp. Las Cascadas R P2 12.78 5.52 UF 275169 Aguascalientia sp. Las Cascadas L P2 12.37 5.23 UF 280213 Aguascalientia sp. Las Cascadas L P2 11.44 4.9 UF 280862 Aguascalientia sp. Las Cascadas L P2 10.45 4.2 UF 280119 Aguascalientia sp. Las Cascadas R P2 11.3 4.69 UF 280670 Floridatragulinae n. gen & Las Cascadas L P2 11.8 6 sp. UF 244316 Aguascalientia sp. Las Cascadas R P2 9.8 4.4

261

Table D-1. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 281471 Aguascalientia sp. Las Cascadas L P2 10.3 4.4 UF 302371 Camelidae Thomas Farm L P3 9.94 6.05 CAST Floridatragulus Thomas Farm R P3 11.01 5.75 dolichanthereus UF 200601 Camelidae Thomas Farm R P3 10.04 5.68 UF 121612 Floridatragulus sp. Thomas Farm R P3 12.06 5.7 UF 196837 Floridatragulus sp. Thomas Farm R P3 12.23 5.21 UF 197400 Floridatragulus sp. Thomas Farm L P3 10.08 6.48 UF 215683 Floridatragulus sp. Thomas Farm R P3 10.16 6.6 UF 273892 Floridatragulus sp. Thomas Farm R P3 11.34 5.75 UF 289277 Floridatragulus sp. Thomas Farm L P3 10.3 5.08 UF 273891 Floridatragulus sp. Thomas Farm R P3 11.6 6.37 UF 206019 Nothokemas floridanus Thomas Farm R P3 12.74 6.65 UF 289251 (MCZ 4322 Nothokemas floridanus Thomas Farm R P3 10.69 7.45 Cast) UF 289275 Nothokemas floridanus Thomas Farm R P3 11.61 8.26 UF 1277 Nothokemas sp. Thomas Farm L P3 10.99 6.69 UF 153870 Nothokemas sp. Thomas Farm R P3 11.23 5.22 UF 197394 Nothokemas sp. Thomas Farm R P3 13.26 8.27 UF 197397 Nothokemas sp. Thomas Farm L P3 11.61 7.54 UF 203393 Nothokemas sp. Thomas Farm L P3 12.35 8.4 UF 216108 Nothokemas sp. Thomas Farm R P3 13.64 8.3 UF 247085 Nothokemas sp. Thomas Farm R P3 11.18 7.66 UF 259340 Nothokemas sp. Thomas Farm L P3 12.51 7.62 UF 269620 Nothokemas sp. Thomas Farm L P3 11.3 6.15 UF 269808 Nothokemas sp. Thomas Farm R P3 12.5 8.7 UF 273885 Nothokemas sp. Thomas Farm R P3 10.8 4.65 UF 273886 Nothokemas sp. Thomas Farm R P3 12.63 5.15

262

Table D-1. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 289276 Nothokemas sp. Thomas Farm R P3 9.78 5.65 UF 68 Nothokemas sp. Thomas Farm L P3 12.23 8.02 UF 87 Nothokemas sp. Thomas Farm L P3 10.68 6.63 UF 6500 Nothokemas sp. Thomas Farm R P3 13.24 6.06 UF 315408 Nothokemas sp. Thomas Farm L P3 12.56 6.98 UF 281478 Aguascalientia Las Cascadas R P3 10.14 5.34 panamaensis UF 280865 Floridatragulinae n. gen & Las Cascadas R P3 9.79 5.96 sp. UF 280865 Floridatragulinae n. gen & Las Cascadas L P3 10.12 6.32 sp. UF 244199 Aguascalientia sp. Las Cascadas L P3 10.6 6.01 UF 254125 Aguascalientia sp. Las Cascadas R P3 10.29 5.72 UF 275169 Aguascalientia sp. Las Cascadas R P3 11.03 5.73 UF 275169 Aguascalientia sp. Las Cascadas L P3 11.3 5.5 UF 275277 Aguascalientia sp. Las Cascadas L P3 10.23 5.9 UF 280722 Aguascalientia sp. Las Cascadas L P3 9.42 5.45 UF 280670 Floridatragulinae n. gen & Las Cascadas L P3 11.6 5.8 sp. UF 280900 Floridatragulinae n. gen & Las Cascadas L P3 10.67 6.02 sp. UF 281473 Aguascalientia sp. Las Cascadas R P3 9.56 6.01 UF 302371 Camelidae Thomas Farm L P4 10.84 10.37 CAST F. dolichanthereus Thomas Farm R P4 9.9 9.9 No number Floridatragulus sp. Thomas Farm R P4 10.12 9.08 UF 200601 Camelidae Thomas Farm R P4 9.26 10.99 UF 164301 Floridatragulus sp. Thomas Farm R P4 11.49 8.68 UF 197399 Floridatragulus sp. Thomas Farm R P4 10.15 10.42 UF 215683 Floridatragulus sp. Thomas Farm R P4 9 10.6 UF 289278 Floridatragulus sp. Thomas Farm L P4 8.69 9.33 UF 289251 (MCZ 4322 Nothokemas floridanus Thomas Farm R P4 11.84 12.86 Cast)

263

Table D-1. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 289275 Nothokemas floridanus Thomas Farm R P4 12.32 11.86 UF 289275 Nothokemas floridanus Thomas Farm L P4 10.85 10.96 UF 172619 Nothokemas sp. Thomas Farm R P4 7.2 10.31 UF 197395 Nothokemas sp. Thomas Farm R P4 10 10.96 UF 247085 Nothokemas sp. Thomas Farm R P4 8.15 10.65 UF 269808 Nothokemas sp. Thomas Farm R P4 9.05 12.25 UF 302369 Nothokemas sp. Thomas Farm R P4 9.17 11.24 UF 315408 Nothokemas sp. Thomas Farm L P4 11.43 11.43 UF 204542 Nothokemas sp. Thomas Farm L P4 12.15 12.39 UF 281478 Aguascalientia Las Cascadas R P4 8.15 8.6 panamaensis UF 280865 Floridatragulinae n. gen & Las Cascadas L P4 8.7 9.42 sp. UF 254125 Aguascalientia sp. Las Cascadas R P4 7.68 8.2 UF 280862 Aguascalientia sp. Las Cascadas L P4 8.1 8.73 UF 280670 Floridatragulinae n. gen & Las Cascadas L P4 9 9.1 sp. UF 280729 Floridatragulinae n. gen & Las Cascadas R P4 8.64 10.54 sp. UF 280738 Floridatragulinae n. gen & Las Cascadas L P4 9.15 8.56 sp. UF 280970 Floridatragulinae n. gen & Las Cascadas L P4 8.84 9.45 sp. UF 246853 Floridatragulus sp. Cucaracha R M1 9.33 10.27 10.41 UF 280240 Floridatragulus sp. Cucaracha L M1 10.3 12.16 12.04 UF 206348 Camelidae Thomas Farm L M1 14.44 16.68 16.55 UF 302371 Camelidae Thomas Farm L M1 16.75 16.39 16.93 UF 271334 Camelidee Thomas Farm R M1 15.66 16.44 15.54 CAST F. dolichanthereus Thomas Farm R M1 12.9 13.22 14.48 UF 200601 Camelidae Thomas Farm R M1 12.76 16.92 18.92 UF 151 Floridatragulus sp. Thomas Farm L M1 14.07 16.04 14.75 UF 19965 Floridatragulus sp. Thomas Farm R M1 14.85 14.7 15.51 UF 211312 Floridatragulus sp. Thomas Farm L M1 11.38 n/a 12.29

264

Table D-1. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 214540 Floridatragulus sp. Thomas Farm L M1 13.42 14.6 14.05 UF 248818 Floridatragulus sp. Thomas Farm L M1 14.11 13.39 13.19 UF 259826 Floridatragulus sp. Thomas Farm R M1 11.7 13.57 14.61 UF 267344 Floridatragulus sp. Thomas Farm L M1 14.92 n/a 13.43 UF 270130 Floridatragulus sp. Thomas Farm L M1 12.09 10.56 11.37 UF 5313 Floridatragulus sp. Thomas Farm L M1 13.7 13.33 15.2 UF 289251 (MCZ 4322) Nothokemas floridanus Thomas Farm R M1 16.46 16.83 17.06 UF 289275 Nothokemas floridanus Thomas Farm R M1 16.32 15.4 16.8 UF 289275 Nothokemas floridanus Thomas Farm L M1 15.82 15.78 16.29 UF 7181 Nothokemas floridanus Thomas Farm R M1 15.21 16.01 16.05 UF 172619 Nothokemas sp. Thomas Farm R M1 13.4 14.46 14.58 UF 181281 Nothokemas sp. Thomas Farm L M1 17.16 16.08 15.52 UF 183801 Nothokemas sp. Thomas Farm R M1 16.53 15.01 15.62 UF 216244 Nothokemas sp. Thomas Farm L M1 15.9 15.35 15.48 UF 245840 Nothokemas sp. Thomas Farm R M1 17.34 18.01 17.82 UF 247085 Nothokemas sp. Thomas Farm R M1 15.82 16.03 16.15 UF 258549 Nothokemas sp. Thomas Farm L M1 15.29 14.92 15.84 UF 259103 Nothokemas sp. Thomas Farm R M1 15.29 14.23 14.6 UF 259819 Nothokemas sp. Thomas Farm L M1 15.6 15.14 18.2 UF 269808 Nothokemas sp. Thomas Farm R M1 10.57 11.4 12.02 UF 300158 Nothokemas sp. Thomas Farm R M1 14.12 15.27 16.43 UF 5304 Nothokemas sp. Thomas Farm R M1 15.92 17.59 17.95 UF 7189 Nothokemas sp. Thomas Farm L M1 12.95 15 14.7 UF 163941 Nothokemas sp. Thomas Farm R M1 15.62 14.7 15.17 UF 254117 Aguascalientia sp. Las Cascadas R M1 12.5 11.44 11.05 UF 275169 Aguascalientia sp. Las Cascadas L M1 11.78 12.39 13.16 UF 275178 Aguascalientia sp. Las Cascadas R M1 11.6 12.84 13.53 UF 275291 Floridatragulinae n. gen & Las Cascadas L M1 10.44 11.98 11.92 sp.

265

Table D-1. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 280739 Aguascalientia sp. Las Cascadas L M1 10.67 12.32 13.41 - UF 280862 Aguascalientia sp. Las Cascadas R M1 10.5 11.4 11.96 - UF 280862 Aguascalientia sp. Las Cascadas R M1 10 10.67 11.97 - UF 280901 Aguascalientia sp. Las Cascadas R M1 10.8 11.83 12.4 - UF 280670 Floridatragulinae n. gen & Las Cascadas L M1 11 11.2 12.2 - sp. STRI 40926 Aguascalientia sp. Las Cascadas R M1 10.76 11.79 - UF 280023 Floridatragulus sp. Cucaracha L M2 11.59 13.26 12.7 - UF 302371 cf. protolabinae Thomas Farm L M2 22.5 22.51 22.17 - UF 265015 cf. protolabinae Thomas Farm R M2 10.94 10.81 10.28 - CAST F. dolichanthereus Thomas Farm R M2 17.46 18.09 17.57 - UF 200601 cf. protolabinae Thomas Farm R M2 19.07 n/a 19.52 - UF 205906 Floridatragulus sp. Thomas Farm L M2 16.73 18.48 18.36 - UF 211312 Floridatragulus sp. Thomas Farm L M2 15.08 15.71 14.69 - UF 248818 Floridatragulus sp. Thomas Farm L M2 16.49 15.72 14.12 - UF 259104 Floridatragulus sp. Thomas Farm R M2 18.12 17.45 16.24 - UF 267334 Floridatragulus sp. Thomas Farm L M2 17.31 16.05 15.29 - UF 267344 Floridatragulus sp. Thomas Farm L M2 18.55 16.13 14.7 - UF 161108 Floridatragulus sp. Thomas Farm L M2 16.02 n/a 17.25 - UF 165809 Nothokemas floridanus Thomas Farm L M2 21.18 18.18 17.09 - UF 18434 Nothokemas floridanus Thomas Farm L M2 16.78 18.72 16.95 - UF 19954 Nothokemas floridanus Thomas Farm R M2 16.53 16.86 15.7 - UF 19954 Nothokemas floridanus Thomas Farm R M2 16.54 16.69 15.68 - UF 271331 Nothokemas floridanus Thomas Farm L M2 17.47 18.73 17.84 - UF 289251 (MCZ 4322 Nothokemas floridanus Thomas Farm R M2 19.34 20.44 19.62 - Cast) UF 289275 Nothokemas floridanus Thomas Farm R M2 18.8 18.69 17.68 - UF 289275 Nothokemas floridanus Thomas Farm L M2 19.65 18.77 17.32 - UF 156229 Nothokemas sp. Thomas Farm L M2 18.16 19.43 17.77 -

Table D-1. Continued

266

Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 172619 Nothokemas sp. Thomas Farm R M2 16.38 17.18 16.07 UF 201766 Nothokemas sp. Thomas Farm L M2 18.41 18.15 16.51 UF 247085 Nothokemas sp. Thomas Farm R M2 17.6 18.12 16.27 UF 281478 Aguascalientia panamaensis Las Cascadas R M2 12.4 n/a 13.5 UF 246825 Floridatragulinae n. gen & sp. Las Cascadas R M2 12.59 10.26 11.93 UF 254116 A. panamaensis Las Cascadas L M2 11.94 12.23 12.17 UF 246857 Floridatragulinae n. gen & sp. Las Cascadas R M2 14.39 17.85 15.89 UF 254125 Aguascalientia sp. Las Cascadas R M2 13.37 15.22 14.27 UF 257197 Floridatragulinae n. gen & sp. Las Cascadas R M2 12.26 14.78 14.23 UF 271620 Floridatragulinae n. gen & sp. Las Cascadas L M2 12.95 15.8 14.83 UF 280744 Aguascalientia sp. Las Cascadas R M2 14.5 16.37 15.89 UF 280862 Aguascalientia sp. Las Cascadas R M2 12.8 13.93 n/a UF 280865 Floridatragulinae n. gen & sp. Las Cascadas L M2 14.44 16.7 14.95 UF 271594 Aguascalientia sp. Las Cascadas R M2 13.46 15.3 13.15 UF 280670 Floridatragulinae n. gen & sp. Las Cascadas L M2 13 15.2 15.4 UF 281477 Floridatragulinae n. gen & sp. Las Cascadas L M2 14.79 17.8 15.24 UF 280859 Floridatragulinae n. gen & sp. Las Cascadas R M2 na na na UF 40279 Floridatragulinae n. gen & sp. Las Cascadas L M2 14.22 15.78 UF 281472 Floridatragulinae n. gen & sp. Las Cascadas L M2 13.48 15.66 UF 193076 Nothokemas floridanus Thomas Farm L M2 19.89 n/a 18.03 UF 275485 Floridatragulus sp. Cucaracha R M3 10.74 12.61 10.92 UF 245482 Floridatragulus sp. Cucaracha L M3 10.62 12.74 10.99 UF 267102 Floridatragulus sp. Cucaracha R M3 10.39 12.72 10.77 UF 275486 Floridatragulus sp. Cucaracha L M3 12.63 14.02 11.71 UF 280991 Floridatragulus sp. Cucaracha L M3 12.05 14.3 12.74 UF 206348 Camelidae Thomas Farm L M3 19.96 18.61 16.65 CAST F. dolichanthereus Thomas Farm R M3 21.74 19.81 18.08

267

Table D-1. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 10893 Floridatragulus sp. Thomas Farm L M3 16.38 16.42 15.89 UF 200601 cf. protolabinae Thomas Farm R M3 20.65 20.03 17.1 UF 185147 Floridatragulus sp. Thomas Farm L M3 15.2 16.71 14.92 UF 19789 Floridatragulus sp. Thomas Farm R M3 13.15 14.39 15.45 UF 19790 Floridatragulus sp. Thomas Farm L M3 13.36 15.49 13.67 UF 19956 Floridatragulus sp. Thomas Farm L M3 14.81 n/a 14.17 UF 206040 Floridatragulus sp. Thomas Farm L M3 17.52 18.08 15.89 UF 216507 Floridatragulus sp. Thomas Farm L M3 13.95 16.14 14.29 UF 268414 Floridatragulus sp. Thomas Farm L M3 16.72 17.51 15.79 UF 60410 Floridatragulus sp. Thomas Farm R M3 18.54 17.49 16.2 UF 60410 Floridatragulus sp. Thomas Farm R M3 16.29 17.03 13.47 UF 67033 Floridatragulus sp. Thomas Farm R M3 15.79 17.77 15.5 UF 7187 Floridatragulus sp. Thomas Farm R M3 13.75 15.34 14.46 UF 197670 Floridatragulus sp. Thomas Farm R M3 18.1 19.23 18.01 UF 156071 Floridatragulus sp. Thomas Farm R M3 16.2 16.58 14.26 UF 183800 Floridatragulus sp. Thomas Farm R M3 17.38 16.53 14.54 UF 18434 Nothokemas floridanus Thomas Farm L M3 16.66 18.25 15.81 UF 289251 Nothokemas floridanus Thomas Farm R M3 19.46 21.73 17.47 UF 289275 Nothokemas floridanus Thomas Farm R M3 20.92 20.16 16.99 UF 289275 Nothokemas floridanus Thomas Farm L M3 22.8 20.26 17.77 UF 211449 Nothokemas sp. Thomas Farm R M3 17.64 16.73 16 UF 6500 Nothokemas sp. Thomas Farm L M3 19.54 17.11 18.01 UF 172605 Nothokemas sp. Thomas Farm R M3 19.9 18.62 16.17 UF 259877 Aguascalientia minuta Las Cascadas R M3 10.72 12.23 11.9 UF 281478 A. panamaensis Las Cascadas R M3 14.1 14.45 12.7 UF 244204 Aguascalientia sp. Las Cascadas R M3 13.3 14.82 12.6 UF 245602 Floridatragulinae n. gen Las Cascadas L M3 13.23 15.63 13.44 & sp.

268

Table D-1. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 254115 Aguascalientia sp. Las Cascadas L M3 12.53 14.08 12.54 UF 254125 Aguascalientia sp. Las Cascadas R M3 12.57 15.33 13.03 UF 280012 Aguascalientia sp. Las Cascadas R M3 13.6 16.06 12.94 UF 280638 Aguascalientia sp. Las Cascadas R M3 12.22 13.72 13.03 UF 280865 Floridatragulinae n. Las Cascadas L M3 12.2 13.8 12.34 gen & sp. UF 280920 Floridatragulinae n. Las Cascadas R M3 12.8 16 15.44 gen & sp. UF 280937 Floridatragulinae n. Las Cascadas R M3 13.44 16.03 12.8 gen & sp. UF 281051 Aguascalientia sp. Las Cascadas L M3 10.77 11.85 12.01 UF 280670 Floridatragulinae n. Las Cascadas L M3 16 16.2 12.5 gen & sp. UF 275169 Floridatragulinae n. Las Cascadas R M3 14 15.83 14.08 gen & sp.

269

Table D-2. Dental measurements (lower dentition) of early Miocene camelids from Southern North America. Abbreviations: BAPL, basal anterior-posterior length. BTWmx: basal maximum transverse width. BTWHyd, basal transverse hypoconulid width. Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 246802 Aguascalientia sp. Las Cascadas R c1 5.76 3.84 UF 275289 Aguascalientia sp. Las Cascadas R c1 5.4 4.21 UF 281059 Aguascalientia sp. Las Cascadas R c1 5.75 3.99 UF 281059 Aguascalientia sp. Las Cascadas L c1 5.29 3.88 UF 19955 Camelidae TF Thomas Farm L dp2 10.64 4.14 UF 215374 Camelidae TF Thomas Farm R dp2 9.99 4.24 UF 193038 Camelidae TF Thomas Farm R dp3 11.7 4.06 UF 7186 Camelidae TF Thomas Farm L dp3 11.4 4.57 UF 246802 Aguascalientia sp. Las Cascadas R p1 8.86 4.06 UF 246802 Aguascalientia sp. Las Cascadas L p1 7.23 4.1 UF 246828 Aguascalientia sp. Las Cascadas L p1 5.55 3.42 UF 275419 Aguascalientia sp. Las Cascadas L p1 5.92 3.48 UF 280214 Floridatragulinae n. Las Cascadas L p1 7.53 4.37 gen & sp. UF 281039 Aguascalientia sp. Las Cascadas L p1 6.93 4.11 UF 281059 Floridatragulinae n. Las Cascadas R p1 6.31 3.56 gen & sp. UF 281469 Aguascalientia sp. Las Cascadas L p1 5.95 3.54 UF 281059 Aguascalientia sp. Las Cascadas R p1 6.32 3.5 UF 281470 Aguascalientia sp. Las Cascadas R p1 6.34 3.81 TMM 31190-28 Floridatragulus Burkeville,Fleming R p2 11.16 3.72 texanus Fm. TMM 31190-28 Floridatragulus Burkeville,Fleming L p2 12.07 3.95 texanus Fm. UF 280653 Floridatragulus sp. Cucaracha L p2 7.58 3.2 TMM 31255-13 Cast of MCZ- Floridatragulus Thomas Farm R p2 10.4 3.57 4086 barbouri UF 165141 Nothokemas Thomas Farm R p2 8.92 4.8 floridanus

270

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 262698 Nothokemas sp. Thomas Farm L p2 10.63 4.6 UF 263816 Floridatragulus sp. Thomas Farm L p2 9.5 2.85 UF 266165 Nothokemas sp. Thomas Farm L p2 11.88 5.07 UF 271322 Nothokemas sp. Thomas Farm R p2 10 4.27 UF 271332 Nothokemas Thomas Farm L p2 9.3 4.37 floridanus UF 273894 Floridatragulus sp. Thomas Farm L p2 9.73 3.44 UF 308889 Nothokemas Thomas Farm L p2 10.88 5.13 floridanus UF 280469 Floridatragulinae n. Las Cascadas R p2 12.15 4.95 gen & sp. UF 254124 A. panamaensis Las Cascadas L p2 10.37 4.3 UF 236939 A. panamaensis Las Cascadas R p2 9.95 4.42 UF 254129 A. panamaensis Las Cascadas L p2 10.31 4.44 TMM 31190-28 Floridatragulus Burkeville,Fleming R p3 11.64 4.6 texanus Fm. TMM 31190-28 Floridatragulus Burkeville,Fleming L p3 11.5 4.88 texanus Fm. STRI 38904 Floridatragulus sp. Cucaracha R P3 8.57 4.83 UF 257201 Floridatragulus sp. Cucaracha L p3 n/a 4.14 UF 275446 Floridatragulus sp. Cucaracha R p3 8.04 3.5 UF 280091 Floridatragulus sp. Cucaracha L p3 8.3 3.44 TMM 31255-13 Cast of MCZ- Floridatragulus Thomas Farm R p3 10.74 4.29 4086 HOLOTYPE barbouri UF 155337 Floridatragulus sp. Thomas Farm L p3 8.42 3.72 UF 165141 Nothokemas Thomas Farm R p3 10.56 5.95 floridanus

271

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 180710 Nothokemas Thomas Farm R p3 13.28 6.3 floridanus UF 195851 Nothokemas sp. Thomas Farm L p3 10.49 5.35 UF 19791 Nothokemas Thomas Farm L p3 10.51 5.13 floridanus UF 199594 Nothokemas Thomas Farm R p3 10.87 n/a floridanus UF 199625 Nothokemas sp. Thomas Farm R p3 12.7 4.94 UF 199640 Nothokemas sp. Thomas Farm R p3 10.59 4.79 UF 203750 Floridatragulus sp. Thomas Farm R p3 10.16 4.6 UF 211450 Nothokemas Thomas Farm R p3 10.07 5.52 floridanus UF 213186 Nothokemas Thomas Farm L p3 11.57 5.22 floridanus UF 223913 Nothokemas Thomas Farm R p3 11.51 5.56 floridanus UF 2415 Floridatragulus sp. Thomas Farm L p3 11.48 n/a UF 257415 Floridatragulus sp. Thomas Farm R p3 9.27 3.21 UF 271297 Floridatragulus sp. Thomas Farm L p3 9.38 3.85 UF 271320 Nothokemas Thomas Farm R p3 11.95 5.92 floridanus UF 271321 Floridatragulus sp. Thomas Farm R p3 9.66 3.37 UF 277996 Nothokemas sp. Thomas Farm L p3 12.45 5.66 UF 278074 Nothokemas Thomas Farm R p3 11.08 6.52 floridanus UF 246803 Aguascalientia sp. Las Cascadas L p3 9.46 4.11 UF 246828 Aguascalientia sp. Las Cascadas L p3 10.24 4.21 UF 254127 Floridatragulinae n. Las Cascadas L p3 12.34 5.22 gen & sp. UF 267142 Aguascalientia sp. Las Cascadas R p3 10.1 4.65 UF 280832 Aguascalientia sp. Las Cascadas R p3 9.92 4.01

272

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 280834 Floridatragulinae n. Las Cascadas L p3 10.5 4.46 gen & sp. UF 281469 Aguascalientia sp. Las Cascadas L p3 9.95 4.17 UF 254113 A. minuta Holotype Las Cascadas L p3 8.45 3.91 UF 254124 A. panamaensis Las Cascadas R p3 10.31 4.37 UF 236939 A. panamaensis Las Cascadas R p3 10.13 4.58 UF 254129 A. panamaensis Las Cascadas L p3 10.19 4.36 TMM 31190-28 Floridatragulus Burkeville,Fleming L p4 11.33 6.28 texanus Fm. UF 246854 Floridatragulus sp. Cucaracha R p4 7.45 4.52 UF 246854 Floridatragulus sp. Cucaracha L p4 8.05 4.7 UF 257201 Floridatragulus sp. Cucaracha L p4 8.9 5.5 UF 271595 Floridatragulus sp. Cucaracha R p4 7.31 4.63 TMM 31255-13 Cast of MCZ- Floridatragulus Thomas Farm R p4 9.34 5.67 4086 HOLOTYPE barbouri UF 153964 Nothokemas Thomas Farm R p4 13.03 6.87 floridanus UF 165141 Nothokemas Thomas Farm R p4 11.85 6.46 floridanus UF 176230 Nothokemas Thomas Farm L p4 13.06 6.78 floridanus UF 176231 Nothokemas sp. Thomas Farm R p4 12.14 7.15 UF 195851 Nothokemas sp. Thomas Farm L p4 11.03 6.12 UF 19779 Floridatragulus sp. Thomas Farm R p4 7.54 6.01 UF 199594 Nothokemas Thomas Farm R p4 12.47 6.84 floridanus UF 211450 Nothokemas Thomas Farm R p4 11.71 6.98 floridanus

273

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 213113 Nothokemas sp. Thomas Farm L p4 11.63 5.33 UF 213186 Nothokemas Thomas Farm L p4 11.98 5.76 floridanus UF 215222 Nothokemas sp. Thomas Farm L p4 11.43 5.91 UF 223913 Nothokemas Thomas Farm R p4 10.72 7.16 floridanus UF 2415 Floridatragulus sp. Thomas Farm L p4 9.04 n/a UF 260015 Nothokemas Thomas Farm L p4 13.83 7 floridanus UF 267301 Nothokemas Thomas Farm R p4 13.4 6.71 floridanus UF 271297 Floridatragulus sp. Thomas Farm R p4 8.77 5.3 UF 271297 Floridatragulus sp. Thomas Farm L p4 8.32 5.4 UF 278074 Nothokemas Thomas Farm R p4 12.4 8.05 floridanus UF19929 Nothokemas Thomas Farm R p4 13.04 6.55 floridanus UF 266644 Floridatragulus sp. Thomas Farm L p4 9.6 5.07 UF 246802 Aguascalientia sp. Las Cascadas R p4 9.94 5.25 UF 246828 Aguascalientia sp. Las Cascadas L p4 9.11 5.09 UF 254118 Aguascalientia sp. Las Cascadas L p4 9.5 5.49 UF 254120 Aguascalientia sp. Las Cascadas L p4 9.6 5.1 UF 275174 Aguascalientia sp. Las Cascadas R p4 9.2 5.1 UF 275276 Aguascalientia sp. Las Cascadas R p4 10.01 5.89 UF 280438 Floridatragulinae n. Las Cascadas L p4 10.85 6.18 gen & sp. UF 280492 Floridatragulinae n. Las Cascadas R p4 10.99 6.23 gen & sp. UF 280877 Aguascalientia sp. Las Cascadas R p4 8.9 5.1 UF 280980 Aguascalientia sp. Las Cascadas L p4 10.05 5.14 UF 281036 Aguascalientia sp. Las Cascadas R p4 9.34 5.7

274

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 281059 Floridatragulinae n. Las Cascadas R p4 9.83 5.3 gen & sp. UF 254113 A. minuta Holotype Las Cascadas R p4 8.34 4.79 UF 254113 A. minuta Holotype Las Cascadas L p4 8.55 4.67 UF 254124 A. panamaensis Las Cascadas L p4 9.35 5.67 Paratype UF 254129 A. panamaensis Las Cascadas L p4 9.73 5.58 Paratype UF 281059 Aguascalientia sp. Las Cascadas R p4 9.81 5.35 TMM 31190-28 Floridatragulus Burkeville,Fleming R m1 12.22 7.8 9.1 texanus Fm. TMM 31190-28 Floridatragulus Burkeville,Fleming L m1 12.7 7.33 9.63 texanus Fm. TMM 31219-266 Floridatragulus Coldspring Fauna, R m1 15.1 11 hesperus UF 246854 Floridatragulus sp. Cucaracha R m1 9.26 6.68 7.37 UF 246854 Floridatragulus sp. Cucaracha L m1 9.15 6.37 7.26 UF 280808 Floridatragulus sp. Cucaracha R m1 8.82 6.08 6.95 TMM 40620-7 Delahomeryx browni Delaho Fm. R m1 11.9 7.5 UF 142115 Nothokemas sp. Thomas Farm R m1 16.44 11.3 11.22 TMM 31255-13 (MCZ-4086) Floridatragulus Thomas Farm R m1 9.85 6.86 8.66 barbouri UF 1270 Nothokemas sp. Thomas Farm L m1 16.09 9.39 10.89 UF 153964 Nothokemas Thomas Farm R m1 16.49 10.57 11.71 floridanus UF 156228 Nothokemas sp. Thomas Farm L m1 16.79 11.76 12.3 UF 163348 Nothokemas Thomas Farm L m1 15.15 8.7 10.31 floridanus UF 165141 Nothokemas Thomas Farm R m1 13.55 12.27 12.41 floridanus UF 171457 Nothokemas sp. Thomas Farm R m1 17.46 10.37 11.44

275

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 176230 Nothokemas Thomas Farm L m1 14.76 n/a 11.22 floridanus UF 180346 Floridatragulus sp. Thomas Farm L m1 11.79 8.26 9.42 UF 181029 Nothokemas sp. Thomas Farm R m1 14.45 9.12 9.99 UF 183417 Nothokemas sp. Thomas Farm R m1 16.31 9.67 10.99 UF 185113 Nothokemas sp. Thomas Farm L m1 18.33 12.59 13.2 UF 185120 Floridatragulus sp. Thomas Farm L m1 12.37 8.42 9.18 UF 188031 Nothokemas sp. Thomas Farm L m1 14.2 9.44 10.24 UF 195851 Nothokemas sp. Thomas Farm L m1 14.59 9.68 10.86 UF 196834 Nothokemas sp. Thomas Farm R m1 15.57 10.48 11.33 UF 19779 Floridatragulus sp. Thomas Farm R m1 12.38 8.15 9.49 UF 19785 Floridatragulus sp. Thomas Farm R m1 11.9 8.53 9.57 UF 199524 Nothokemas sp. Thomas Farm R m1 15.47 9.51 10.42 UF 199594 Nothokemas Thomas Farm R m1 14.87 9.57 10.81 floridanus UF 203720 Nothokemas sp. Thomas Farm R m1 13.9 9.29 10.34 UF 204596 Nothokemas sp. Thomas Farm L m1 15.14 9.99 10.8 UF 210134 Nothokemas sp. Thomas Farm R m1 13.05 8.45 8.88 UF 211450 Nothokemas Thomas Farm R m1 14.71 10.05 11.07 floridanus UF 211555 Nothokemas sp. Thomas Farm L m1 15.54 9.63 10.89 UF 215807 Nothokemas sp. Thomas Farm L m1 15.28 9.18 10.81 UF 216417 Floridatragulus sp. Thomas Farm R m1 11.34 7.65 8.67 UF 223913 Nothokemas Thomas Farm R m1 15.2 11.2 11 floridanus UF 2415 Floridatragulus sp. Thomas Farm L m1 12.96 9.72 12.19 UF 260015 Nothokemas Thomas Farm L m1 15.17 9.85 10.72 floridanus UF 271297 Floridatragulus sp. Thomas Farm L m1 10.77 9.11 9.58

276

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 278074 Nothokemas Thomas Farm R m1 15.72 10.43 11.77 floridanus UF 289274 (MCZ 3635 Floridatragulus Thomas Farm L m1 12.85 7.35 8.56 CAST) dolichanthereus UF 314400 Nothokemas sp. Thomas Farm R m1 17.74 11 12 UF 5680 Nothokemas sp. Thomas Farm L m1 16.67 11.56 12.44 UF19929 Nothokemas Thomas Farm R m1 14.92 9.57 10.86 floridanus UF 246802 Aguascalientia sp. Las Cascadas R m1 10.06 6.72 8.09 UF 246828 Aguascalientia sp. Las Cascadas L m1 9.54 6.14 7.12 UF 254122 Aguascalientia sp. Las Cascadas L m1 9.36 6.05 7.7 UF 280125 Aguascalientia sp. Las Cascadas L m1 9.39 N/A N/A UF 280181 Aguascalientia sp. Las Cascadas L m1 10.4 7.21 8.15 UF 280492 Floridatragulinae n. Las Cascadas L m1 12.25 7.6 9.7 gen & sp. UF 280492 Floridatragulinae n. Las Cascadas R m1 11.7 7.15 9.03 gen & sp. UF 280803 Aguascalientia sp. Las Cascadas L m1 10.9 7.7 8.99 UF 280968 Floridatragulinae n. Las Cascadas L m1 12.53 9.54 9.54 gen & sp. UF 281056 Aguascalientia sp. Las Cascadas L m1 11.34 6.74 7.56 UF 281059 Floridatragulinae n. Las Cascadas R m1 11.34 7.3 8.44 gen & sp. UF 281469 Floridatragulinae n. Las Cascadas L m1 10.56 6.76 7.7 gen & sp. UF 254113 A. minuta Holotype Las Cascadas R m1 9.12 6.15 6.76 UF 254113 A. minuta Holotype Las Cascadas L m1 9.21 5.98 6.93 UF 236939 A. panamaensis Las Cascadas R m1 9.4 6.25 7.06 UF 280492 Floridatragulinae n. Las Cascadas R m1 7.23 8.8 gen & sp. UF 281059 Aguascalientia sp. Las Cascadas R m1 10.12 6.95 8.32 TMM 41526-36 A. wilsoni type Zoyotal L. F. X m1 9.6 7.2 TMM 31190-28 Floridatragulus Burkeville,Fleming R m2 17.82 10.48 11.36 texanus Fm.

277

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) TMM 31190-28 Floridatragulus Burkeville,Fleming L m2 17.45 10.58 11.97 texanus Fm. TMM 31219-266 Floridatragulus Coldspring Fauna R m2 19.2 12.6 hesperus UF 246854 Floridatragulus sp. Cucaracha L m2 11.7 8.85 9.4 UF 271595 Floridatragulus sp. Cucaracha R m2 11.39 8.53 9.01 TMM 40620-7 Delahomeryx browni Delaho Fm. R m2 14.4 8.9 TMM 31255-13 Floridatragulus Thomas Farm R m2 14.77 10.48 10.54 barbouri UF 1267 Nothokemas Thomas Farm L m2 16.96 11.47 12.27 floridanus UF 153964 Nothokemas Thomas Farm R m2 18.1 13.39 13.32 floridanus UF 162299 Nothokemas sp. Thomas Farm R m2 15.58 10.4 11.01 UF 163348 Nothokemas Thomas Farm L m2 16.06 10.57 11.59 floridanus UF 165141 Nothokemas Thomas Farm R m2 17.72 12.41 12.53 floridanus UF 171457 Nothokemas sp. Thomas Farm R m2 22.36 14.2 13.25 UF 176230 Nothokemas Thomas Farm L m2 17.97 11.49 13.86 floridanus UF 179897 N. floridanus Thomas Farm L m2 15.35 11.3 11.68 UF 182196 Nothokemas sp. Thomas Farm R m2 18.3 12.85 12.75 UF 188057 N. floridanus Thomas Farm L m2 16.88 12.75 12.7 UF 195851 Nothokemas sp. Thomas Farm L m2 16.87 11.74 12.56 UF 19779 Floridatragulus sp. Thomas Farm R m2 15.34 12.03 n/a UF 19785 Floridatragulus sp. Thomas Farm R m2 17.04 12.96 12.88 UF 19813 Nothokemas Thomas Farm R m2 19.8 12.54 12.88 floridanus UF 199524 Nothokemas sp. Thomas Farm R m2 18.3 12.31 12.2

278

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 199594 Nothokemas Thomas Farm R m2 17.87 11.44 12.07 floridanus UF 199621 Nothokemas Thomas Farm R m2 18.51 12.37 12.1 floridanus UF 203400 Nothokemas Thomas Farm L m2 18.5 13.09 13.38 floridanus UF 206349 Nothokemas sp. Thomas Farm L m2 15.62 10.15 11.25 UF 211450 Nothokemas Thomas Farm R m2 18.4 12.98 12.96 floridanus UF 215132 Floridatragulus sp. Thomas Farm L m2 16.3 11.03 11.5 UF 216300 Nothokemas Thomas Farm R m2 18.16 11.7 12.21 floridanus UF 223913 Nothokemas Thomas Farm R m2 18.34 12.35 12.33 floridanus UF 2415 Floridatragulus sp. Thomas Farm L m2 15.5 13.47 n/a UF 259078 Nothokemas Thomas Farm L m2 15.9 11.9 12.41 floridanus UF 259213 Nothokemas sp. Thomas Farm R m2 19.7 13 12.79 UF 266163 Nothokemas sp. Thomas Farm R m2 18.9 12.1 13.25 UF 268160 Nothokemas sp. Thomas Farm L m2 20.31 12.53 12.4 UF 271297 Floridatragulus sp. Thomas Farm R m2 14.13 11.59 12.52 UF 271297 Floridatragulus sp. Thomas Farm L m2 14.01 11.27 12.11 UF 276539 Nothokemas sp. Thomas Farm L m2 16.02 10.06 11.39 UF 278074 N. floridanus Thomas Farm R m2 18.89 12.83 13.68 UF 289274 Floridatragulus Thomas Farm R m2 15.59 10.81 11.15 dolichanthereus UF 289274 Floridatragulus Thomas Farm L m2 14.83 9.88 10.39 dolichanthereus UF 308799 Floridatragulus sp. Thomas Farm R m2 15.73 9.54 10.47 UF 314400 Nothokemas sp. Thomas Farm R m2 20.2 13.73 13.76

279

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 5680-2 Nothokemas sp. Thomas Farm R m2 20.23 12.65 12.64 UF 6471 Nothokemas sp. Thomas Farm R m2 16.97 12.01 13.55 UF 7190 Nothokemas sp. Thomas Farm L m2 15.93 9.88 11.35 UF 19929 N. floridanus Thomas Farm R m2 17.78 11.62 12.77 UF 246802 Aguascalientia sp. Las Cascadas R m2 14.57 9.87 10.03 UF 246836 A. minuta Las Cascadas L m2 11.82 8.33 9 UF 254121 Aguascalientia sp. Las Cascadas L m2 12.79 8.2 9.34 UF 271622 Floridatragulinae n. Las Cascadas L m2 14.86 9.5 10.1 gen & sp. UF 271627 Floridatragulinae n. Las Cascadas R m2 13.8 9.84 10.4 gen & sp. UF 275168 Floridatragulinae n. Las Cascadas L m2 14 9.1 10.08 gen & sp. UF 280017 Aguascalientia sp. Las Cascadas L m2 11.8 8.32 UF 280492 Floridatragulinae n. Las Cascadas R m2 14.94 10.35 10.52 gen & sp. UF 281038 Aguascalientia sp. Las Cascadas L m2 13.55 9.2 10.01 UF 281059 Floridatragulinae n. Las Cascadas R m2 14.13 9.64 10.28 gen & sp. UF 280821 Aguascalientia sp. Las Cascadas R m2 11.17 8.95 9.44 UF 281469 Aguascalientia sp. Las Cascadas R m2 12.99 9.01 9.97 UF 281469 Aguascalientia sp. Las Cascadas L m2 13.47 8.91 9.88 UF 254113 A. minuta Holotype Las Cascadas R m2 10.76 7.66 7.92 UF 254113 A. minuta Holotype Las Cascadas L m2 10.75 8.6 9 UF 254124 A. panamaensis Las Cascadas L m2 12.19 8.83 9.26 UF 236939 A. panamaensis Las Cascadas R m2 13.29 8.74 9.96 UF 280492 Floridatragulinae n. Las Cascadas R m2 10.1 10.2 gen & sp. UF 281059 Aguascalientia sp. Las Cascadas R m2 13.98 9.99 10.46 TMM 41526-36 A. wilsoni type Zoyotal L. F. X m2 13.2 8.9 UF 217741 Palaeolama Bermont R m3 29.67 14.68 13.4 7.78 UF 8887 Palaeolama Bermont L m3 28.5 14.04 13.64 9 UF 226513 Palaeolama Bermont L m3 28.99 13.82 13.99 7.43

280

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 226516 Palaeolama Bermont L m3 28.99 15.18 13.63 8.5 UF 226519 Palaeolama Bermont L m3 32 15.7 n/a 8.66 UF 88775 Palaeolama Bermont L m3 30.6 14.41 13.3 7.93 UF 226520 Palaeolama Bermont L m3 31.98 15.08 14.34 8.62 UF 226515 Palaeolama Bermont L m3 30.29 14.19 13.25 7.25 UF 226517 Palaeolama Bermont L m3 29.26 14.94 13.85 8.04 UF 226518 Palaeolama Bermont L m3 28.16 14.93 13.51 7.14 UF 8382 Palaeolama Bermont L m3 28.01 14.21 12.28 7.22 UF 82548 Palaeolama Bermont L m3 29.27 13.77 13.4 7.49 UF 81457 Palaeolama Bermont L m3 28.12 n/a 13.35 8.5 UF 226523 Palaeolama Bermont R m3 31.6 15.3 14.2 8.1 UF 226502 Palaeolama Bermont R m3 29.2 15.14 14.22 8.4 UF 226507 Palaeolama Bermont R m3 29.03 15.64 13.7 8.33 UF 226500 Palaeolama Bermont R m3 31.82 14.03 13.6 8.5 UF 226509 Palaeolama Bermont R m3 28.47 14.56 13.37 7.66 UF 67492 Palaeolama Bermont R m3 29.64 14.75 12.95 7.56 UF 226499 Palaeolama Bermont R m3 30.22 14.39 14.04 8.35 UF 226505 Palaeolama Bermont R m3 30.85 15.03 14.1 9.15 UF 226504 Palaeolama Bermont R m3 28.18 14.4 13.7 8.47 UF 84146 Palaeolama Bermont R m3 29.14 15.42 14.01 8.29 UF 226508 Palaeolama Bermont R m3 28.52 14.21 12.85 7.76 UF 83028 Palaeolama Bermont R m3 30.23 13.99 13.13 7.83 UF 226503 Palaeolama Bermont R m3 29.26 15.01 13.53 8.4 UF 226501 Palaeolama Bermont R m3 31.76 14.89 13.87 7.9 UF 83638 Palaeolama Bermont R m3 29.7 14.01 13.25 7.57 UF 805109 Palaeolama Bermont R m3 32 15.72 n/a 8.92 TMM 31190-28 F. texanus Fleming Fm. R m3 24.15 11.92 12.46 8.09 TMM 31190-28 F. texanus Fleming Fm. L m3 24.34 12.41 12.73 9.32

281

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) TMM 40693-25 Aguascalientia sp. Castolon L. F. X m3 15.3 8.1 TMM 31219-266 Floridatragulus Coldspring Fauna, R m3 29.5 12.8 hesperus UF 246854 Floridatragulus sp. Cucaracha R m3 16.69 9.35 9.12 5.3 UF 271595 Floridatragulus sp. Cucaracha R m3 18.31 9.33 8.77 UF 280737 Floridatragulus sp. Cucaracha R m3 16.22 9.18 8.26 5.4 TMM 40620-7 Delahomeryx browni Delaho Fm. R m3 19.9 9.9 TMM 40635-25 Delahomeryx browni Delaho Fm. R m3 21.1 9.5 TMM 31255-13 Cast of MCZ- Floridatragulus Thomas Farm R m3 23.7 12.24 12.19 8.73 4086 barbouri UF 153964 Nothokemas Thomas Farm R m3 26.54 13.79 13.66 7.07 floridanus UF 163348 Nothokemas Thomas Farm L m3 24.25 10.91 10.96 6.71 floridanus UF 165141 Nothokemas Thomas Farm R m3 25.61 12.67 13.01 7.47 floridanus UF 176230 Nothokemas Thomas Farm L m3 27 14.21 13.91 9.11 floridanus UF 183545 Floridatragulus sp. Thomas Farm R m3 23.11 13.27 11.7 8 UF 195851 Nothokemas sp. Thomas Farm L m3 25.32 11.67 11.8 6.23 UF 19779 Floridatragulus sp. Thomas Farm R m3 23 14 13.24 8.41 UF 19813 Nothokemas Thomas Farm R m3 29.45 13.9 n/a 9.25 floridanus UF 199594 Nothokemas Thomas Farm R m3 24.35 11.9 11.54 7.24 floridanus UF 203863 Floridatragulus sp. Thomas Farm L m3 20.54 10.7 10.86 6.91 UF 211450 Nothokemas Thomas Farm R m3 23.96 12.36 12.08 7.42 floridanus UF 214527 Floridatragulus sp. Thomas Farm R m3 24.9 n/a 12.81 6.73 UF 214851 Nothokemas sp. Thomas Farm L m3 26.34 11.8 11.53 6.97

282

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 223913 Nothokemas Thomas Farm R m3 28.69 13.36 13.17 8.79 floridanus UF 2415 Floridatragulus sp. Thomas Farm L m3 24.05 n/a n/a n/a UF 2415 Floridatragulus sp. Thomas Farm R m3 24.66 13.98 13.17 7.8 UF 258294 Floridatragulus sp. Thomas Farm R m3 18.29 9.73 10.74 6.49 UF 259078 Nothokemas Thomas Farm L m3 24.06 12.68 12.97 7.31 floridanus UF 260015 Nothokemas Thomas Farm L m3 29.98 14.14 15.03 8.18 floridanus UF 262026 Floridatragulus sp. Thomas Farm L m3 21.8 11.59 11.43 7.27 UF 271297 Floridatragulus sp. Thomas Farm R m3 23.15 13.33 12.8 9.14 UF 271297 Floridatragulus sp. Thomas Farm L m3 23.35 13.34 12.42 7.49 UF 271330 Nothokemas Thomas Farm R m3 25.6 11.33 10.45 6.76 floridanus UF 271333 Floridatragulus sp. Thomas Farm L m3 21.05 12.01 11.5 6.25 UF 278074 Nothokemas Thomas Farm R m3 28.56 14.34 n/a 8.53 floridanus UF 289274 (MCZ 3635) Floridatragulus Thomas Farm L m3 25.3 12.03 13.06 7.53 dolichanthereus UF 314400 Nothokemas sp. Thomas Farm R m3 29.16 15.17 14.62 6.74 UF 7185 Floridatragulus sp. Thomas Farm L m3 26.59 14.74 13.39 9.71 UF 19785 Floridatragulus sp. Thomas Farm R m3 22.79 14.33 14.45 n/a UF 246836 A. minuta Las Cascadas L m3 16.71 9.14 8.39 5.6 UF 254123 Aguascalientia sp. Las Cascadas L m3 17.95 9.31 9.17 6.45 UF 254123 Aguascalientia sp. Las Cascadas L m3 17.6 9 5.37 UF 257196 Floridatragulinae n. Las Cascadas R m3 19.26 10.07 10.27 6.3 gen & sp. UF 257198 Aguascalientia sp. Las Cascadas L m3 17.9 9.83 9.76 6.17 UF 275168 Floridatragulinae n. Las Cascadas L m3 20.32 10.46 9.88 6.5 gen & sp. UF 275195 Aguascalientia sp. Las Cascadas R m3 20.55 11.22 11.3 8.02

283

Table D-2. Continued Cat/ # Taxon Formation/Fauna R/L Tooth BAPL(mm) BTWa BTWp HydW position (mm) (mm) (mm) UF 275195 Floridatragulinae n. Las Cascadas R m3 20.6 11.11 7.6 gen & sp. UF 280049 A. minuta Las Cascadas L m3 16.26 8.6 8.2 5.75 UF 280492 Floridatragulinae n. Las Cascadas R m3 21.67 10.7 n/a 7.09 gen & sp. UF 280664 Floridatragulinae n. Las Cascadas L m3 21.61 11.09 10.75 7.47 gen & sp. UF 280821 Aguascalientia sp. Las Cascadas R m3 18.4 9.97 10.05 6 UF 281059 Floridatragulinae n. Las Cascadas R m3 n/a 10.63 10.23 n/a gen & sp. UF 281059 Aguascalientia sp. Las Cascadas R m3 18.95 10.45 n/a UF 281469 Aguascalientia sp. Las Cascadas R m3 19.38 10.01 9.24 5.95 UF 281469 Aguascalientia sp. Las Cascadas L m3 18.87 9.98 9.46 5.63 UF 254113 A. minuta Holotype Las Cascadas R m3 15.9 8.22 7.84 5.2 UF 254113 A. minuta Holotype Las Cascadas L m3 16.01 8.01 7.83 5.1 UF 254124 A. panamaensis Las Cascadas L m3 18.34 9.6 9.44 5.81 UF 236939 A. panamaensis Las Cascadas R m3 19.69 9.44 9.87 6.17 STRI 40266 Camelidae inc sed Las Cascadas L m3 19.03 10.12 9.8 6.45 TMM 40047-194 Floridatragulus Oakville Fm. L m3 20.49 10.34 9.85 7.19 nanus TMM 41526-36 A. wilsoni Zoyotal L. F. X m3 18.1 9.1

284

APPENDIX E STATISTICAL SUMMARY OF THE TOOTH DIMENSIONS OF THE CAMELID SAMPLE STUDIED.

Table E-1. Lower m3 dimensions. Abbreviations: Alv, Measured on alveoli; Apl, Anterior-Posterior Length; Tw, Transverse Width; Twhyd, Hypoconulid Transverse Width; S, Standard Deviation; V, Index of Variance. Paleolama mirifica Floridatragulus sp. nov. (Panama) APL(mm) TW(mm) Twhyd(mm) APL(mm) TW(mm) Twhyd(mm) N 28.00 N 28.00 N 28.00 N 3.00 N 3.00 N 3.00 Min 28.01 Min 13.77 Min 7.14 Min 16.37 Min 9.32 Min 5.30 Max 32.00 Max 15.72 Max 9.15 Max 18.47 Max 9.52 Max 5.97 Mean 29.83 Mean 14.69 Mean 8.08 Mean 17.13 Mean 9.41 Mean 5.56 Std. error 0.24 Std. error 0.11 Std. error 0.10 Std. error 0.67 Std. error 0.06 Std. error 0.21 Variance 1.67 Variance 0.34 Variance 0.31 Variance 1.35 Variance 0.01 Variance 0.13 Stand. dev 1.29 Stand. 0.59 Stand. 0.55 Stand. 1.16 Stand. dev 0.10 Stand. 0.36 dev dev dev dev Median 29.46 Median 14.72 Median 8.07 Median 16.55 Median 9.40 Median 5.40 25 prcntil 28.99 25 prcntil 14.20 25 prcntil 7.59 25 prcntil 16.37 25 prcntil 9.32 25 prcntil 5.30 75 prcntil 30.79 75 prcntil 15.13 75 prcntil 8.49 75 prcntil 18.47 75 prcntil 9.52 75 prcntil 5.97 Geom. 29.81 Geom. 14.68 Geom. 8.06 Geom. 17.10 Geom. 9.41 Geom. 5.55 mean mean mean mean mean mean Coeff. var 4.33 Coeff. 3.99 Coeff. 6.87 Coeff. var 6.79 Coeff. var 1.07 Coeff. 6.50 var var var

285

Table E-1. Continued Floridatragulus nanus Floridatragulus texanus APL(mm) TW(mm) Twhyd(mm) APL(mm) TW(mm) Twhyd(mm) N 1.00 N 1.00 N 1.00 N 2.00 N 2.00 N 2.00 Min 20.49 Min 10.34 Min 10.34 Min 24.15 Min 12.46 Min 8.09 Max 20.49 Max 10.34 Max 10.34 Max 24.34 Max 12.73 Max 9.32 Mean 20.49 Mean 10.34 Mean 10.34 Mean 24.25 Mean 12.60 Mean 8.71 Std. error 0.00 Std. 0.00 Std. 0.00 Std. error 0.10 Std. 0.14 Std. 0.62 error error error error Variance 0.00 Variance 0.00 Variance 0.00 Variance 0.02 Variance 0.04 Variance 0.76 Stand. 0.00 Stand. 0.00 Stand. 0.00 Stand. 0.13 Stand. 0.19 Stand. 0.87 dev dev dev dev dev dev Median 20.49 Median 10.34 Median 10.34 Median 24.25 Median 12.60 Median 8.71 25 prcntil 10.25 25 5.17 25 5.17 25 prcntil 18.11 25 9.35 25 6.07 prcntil prcntil prcntil prcntil 75 prcntil 10.25 75 5.17 75 5.17 75 prcntil 18.26 75 9.55 75 6.99 prcntil prcntil prcntil prcntil Geom. 20.49 Geom. 10.34 Geom. 10.34 Geom. 24.24 Geom. 12.59 Geom. 8.68 mean mean mean mean mean mean Coeff. var 0.00 Coeff. 0.00 Coeff. 0.00 Coeff. var 0.55 Coeff. 1.52 Coeff. 9.99 var var var var

286

Table E-1. Continued Aguascalientia sp. Castolon Aguascalientia Delahomeryx browni L. F wilsoni APL TW APL TW APL TW (mm) (mm) (mm) (mm) (mm) (mm) N 1.00 N 1.00 N 2.00 N 2.00 N 2.00 N 2.00 Min 15.30 Min 8.10 Min 17.90 Min 9.10 Min 19.90 Min 9.50 Max 15.30 Max 8.10 Max 18.10 Max 9.50 Max 21.10 Max 9.90 Mean 15.30 Mean 8.10 Mean 18.00 Mean 9.30 Mean 20.50 Mean 9.70 Std. 0.00 Std. 0.00 Std. 0.10 Std. 0.20 Std. 0.60 Std. 0.20 error error error error error error Variance 0.00 Variance 0.00 Variance 0.02 Variance 0.08 Variance 0.72 Variance 0.08 Stand. 0.00 Stand. 0.00 Stand. 0.14 Stand. 0.28 Stand. 0.85 Stand. 0.28 dev dev dev dev dev dev Median 15.30 Median 8.10 Median 18.00 Median 9.30 Median 20.50 Median 9.70 25 7.65 25 4.05 25 13.43 25 6.83 25 14.93 25 7.13 prcntil prcntil prcntil prcntil prcntil prcntil 75 7.65 75 4.05 75 13.58 75 7.13 75 15.83 75 7.43 prcntil prcntil prcntil prcntil prcntil prcntil Geom. 15.30 Geom. 8.10 Geom. 18.00 Geom. 9.30 Geom. 20.49 Geom. 9.70 mean mean mean mean mean mean Coeff. 0.00 Coeff. 0.00 Coeff. 0.79 Coeff. 3.04 Coeff. 4.14 Coeff. 2.92 var var var var var var

287

Table E-1. Continued Aguascalientia Floridatragulus minuta dolichanthereus APL TW Twhyd (mm) APL TW Twhyd (mm) (mm) (mm) (mm) (mm) N 4.00 N 4.00 N 4.00 N 14.00 N 14.00 N 13.00 Min 15.90 Min 8.01 Min 5.10 Min 18.29 Min 9.73 Min 6.25 Max 16.71 Max 9.14 Max 5.75 Max 26.59 Max 14.74 Max 9.71 Mean 16.22 Mean 8.49 Mean 5.41 Mean 23.02 Mean 12.79 Mean 7.73 Std. error 0.18 Std. 0.25 Std. 0.16 Std. error 0.57 Std. error 0.38 Std. 0.29 error error error Variance 0.13 Variance 0.25 Variance 0.10 Variance 4.52 Variance 2.01 Variance 1.10 Stand. 0.36 Stand. 0.50 Stand. 0.31 Stand. 2.13 Stand. 1.42 Stand. 1.05 dev dev dev dev dev dev Median 16.14 Median 8.41 Median 5.40 Median 23.13 Median 13.17 Median 7.53 25 prcntil 15.93 25 8.06 25 5.13 25 prcntil 21.61 25 prcntil 11.91 25 6.82 prcntil prcntil prcntil 75 prcntil 16.60 75 9.01 75 5.71 75 prcntil 24.72 75 prcntil 13.99 75 8.57 prcntil prcntil prcntil Geom. 16.22 Geom. 8.48 Geom. 5.41 Geom. 22.92 Geom. 12.71 Geom. 7.66 mean mean mean mean mean mean Coeff. var 2.22 Coeff. 5.84 Coeff. 5.76 Coeff. 9.23 Coeff. 11.08 Coeff. 13.55 var var var var var

288

Table E-1. Continued Aguascalientia panamaensis Floridatragulinae n. gen & sp. APL TW Twhyd (mm) APL TW Twhyd (mm) (mm) (mm) (mm) (mm) N 9.00 N 9.00 N 9.00 N 7.00 N 7.00 N 7.00 Min 17.60 Min 9.00 Min 5.37 Min 18.71 Min 9.69 Min 5.68 Max 20.00 Max 11.22 Max 8.02 Max 21.61 Max 11.11 Max 7.60 Mean 18.76 Mean 9.82 Mean 6.17 Mean 19.88 Mean 10.46 Mean 6.75 Std. error 0.27 Std. error 0.21 Std. 0.25 Std. error 0.40 Std. 0.19 Std. 0.25 error error error Variance 0.67 Variance 0.40 Variance 0.58 Variance 1.11 Variance 0.26 Variance 0.43 Stand. 0.82 Stand. 0.63 Stand. 0.76 Stand. 1.05 Stand. 0.51 Stand. 0.65 dev dev dev dev dev dev Median 18.86 Median 9.83 Median 6.00 Median 20.01 Median 10.46 Median 6.70 25 prcntil 18.05 25 prcntil 9.38 25 5.72 25 prcntil 18.92 25 10.12 25 6.45 prcntil prcntil prcntil 75 prcntil 19.54 75 prcntil 10.00 75 6.31 75 prcntil 20.53 75 11.09 75 7.47 prcntil prcntil prcntil Geom. 18.74 Geom. 9.80 Geom. 6.14 Geom. 19.85 Geom. 10.45 Geom. 6.72 mean mean mean mean mean mean Coeff. 4.36 Coeff. 6.41 Coeff. 12.33 Coeff. var 5.29 Coeff. 4.89 Coeff. 9.66 var var var var var

289

APPENDIX E DESCRIPTION OF DENTAL CHARACTERS USED IN THE PHYLOGENETIC ANALYSIS OF EARLY MIOCENE CAMELIDAE (CHAPTER 3). ALL CHARACTERS TREATED AS UNORDERED.

1) Distance from anterior root of P2 to posterior root of upper canine shorter than muzzle width measured at P1 (0); longer (1).

2) Fusion of the symphysis. absent (0); present (1).

3) Ventral inflection of the symphysis: absent or anterior to p2 (0); present below p2 (1).

4) Lower p1 diastemata: posterior diastema longer than anterior, p1 closer to c1, (0); p1 with anterior and posterior diastemat, subequal in length, more elongate mandible (1).

5) Invagination on lower m3: entoconulid projection absent, only one grinding surface on posterior heel (0); entoconulid projection present but forming a cleft on the lingual side of the posterior heel (1); entoconulid projection present reaching the posterior side of heel (2).

6) Lower p1: incisiform or transversely compressed TW<<

7) Lower p1: present (0); absent (1).

8) Lower p2-p3 diastema: absent (0); present (1).

9) Ectostylids on lower molars: absent or present only on m1 (0); present in m1-m2.

10) Bulbous paraconids on lower p2: absent (0); present (1).

11) Blade-like paraconids on lower p3: absent (0); present (1).

12) Upper P2 parastyle morphology and relative size: distinct but low (0); conical and more distict (1).

13) Entostylids upper molars: absent (0); present (1).

290

14) Lower p4 occlusal outline: APL TW: wedgeshaped, posterior width >>> anterior width (0); oval, characterized by ant and posterior similar transverse widths (1).

15) Depth of mandible below lower p4: Depth < p3-p4 APL (0); > or equal to p3-p4 APL

(1).

16) Lower p4APL > p3 APL (0); p4 APL < or equal to p3 (1).

17) Lower molars transversely compressed: absent (m1APL/TW < 1.5 (0): > 1.5. (1).

18) Maxillary constriction posterior to P1. Absent (0); present (1).

19) Protostylids on lower molars: absent (0); present (1).

20) Morphology of the symplysis: shorter than m1-m3 APL (0); longer than m1-m3 APL

(1).

21) Depth of the mandible below m3: < or equal to m3 APL (0); longer than m3 APL (1).

22) Lower canine: incisiform or transversely reduced (0); caniniform, conical (1)

23) Relative size of lower p2: APLp2APLp4 (1).

24) Lower p1 roots: one single to double rooted (appresed); bulbous fused roots (1).

25) Relative size of I3: smaller than Canine (0); larger (1).

26) Upper P3 cingulum: absent or interrupt (0); complete (1).

27) Ribs on upper molars: weak, not as developed as the mesostyle (0); strong, similar to the mesostyle (1).

28) Maxillary fossa: absent to shallow (0); with distinct border and/or pocketed (1).

29) Postorbital bar: absent, orbit posteriorly open (0); present (1).

30) Lingual stylids on lower p2-p3: absent (0); present (1).

291

31) Camelid hook on ascending ramus: absent or below the occlusal plane of m3, distance to condyle larger than that to the angle (0); near the occlusal plane of m3 (1); above, distance to condyle shorter than distance to the angle (2).

32) Paraconid on lower p2: absent (0); distinct (1).

33) Mesostyle on upper molars: absent to weak (0); present and distinct (1).

34) Metastylids on lower molars: absent (0); present (1).

292

APPENDIX F CHARACTER-TAXON MATRIX USED IN THE PHYLOGENETIC ANALYSES OF EARLY MIOCENE CAMELIDAE (CHAPTER 3). SEE APPENDIX F FOR CHARACTER DESCRIPTIONS.

1 1 2 3

1234567890 1234567890 1234567890 1234

Eotylopus reedi 00000000?0 00?1000000 000000000? 0000

Poebrotherium sp. 0000000000 0000000000 1000000000 0000

A. panamaensis 1101210011 0111110001 1110?01??0 ?111

A. minuta ?101210010 0?11110?01 1110??1??0 ?111

A. wilsoni ?101210011 0??1110?01 1110?????0 ?1?1

F. dolichanthereus 11012?0110 0111110001 1110?01?10 2?11

Floridatragulus sp. nov ?1012?0110 0?11?10?01 1110?01??0 ?011

F. texanus ??0?2??110 0??1110?0? 1?1??????0 ?0?1

N. waldropi ?01?1?1000 100000000? 010??01??1 1111

N. floridanus ?01?1?1010 101000000? 0?0??01??1 1111

G. stenbergi 1101100010 1010000000 0100?01011 1011

Floridatragulinae n. 110120001? ?0111?011? 1?01101010 ??11 gen & sp.

T. brachydontus 1101000000 0001000111 0101010110 2011

O. longipes 1100000000 0000101000 1100110010 2011

'"P". franki' 1001??0000 100?00000? ??00000??? ?011

Camelidae Buda L.F ????1???10 1?11??0?0? ??0???0??? ?011

M. agatensis 1100000001 0000101100 000?010110 1011

293

APPENDIX G DENTAL MEASUREMENTS OF EARLY MIOCENE TAYASSUIDS FROM PANAMA

Table G-1. Dental measurements of tayassuids from the early Miocene of Panama. Abbreviations: APL, anterior-posterior length. TWmx: maximum transverse width. TWHyd: transverse hypoconulid width. Taxon Cataloge number R Tooth BAPL BTWa BTWp BTW APLhyd /L positio (mm) (mm) (mm) hyd (mm) n (mm) Hesperhyinae n. UF 267027 R DP3 8.85 6.78 - - - gen. A & sp. A “Cynorca FAM 73665 R DP3 8.56 6.72 - - - occidentale” “Cynorca FAM 73665 L DP3 8.84 6.44 - - - occidentale” Hesperhyinae n. UF 275270 R DP4 10.51 9.97 - - - gen. A & sp. A “Cynorca FAM 73665 R DP4 8.46 9.63 - - - occidentale” “Cynorca FAM 73665 L DP4 8.17 9.22 - - occidentale” Hesperhyinae n. UF 234400 R P1 4.83 2.66 - - - gen. A & sp. B Hesperhyinae n. UF 234400 L P1 4.62 2.63 - - - gen. A & sp. B Hesperhyinae n. UF 234400 R P2 9.45 5.88 - - - gen. A & sp. B Hesperhyinae n. UF 234400 L P2 9.3 5.78 - - - gen. A & sp. B Hesperhyinae, gen. UF 280442 R p2 10.2 4.99 - - - B Dyseohyus FAM 73678 L P2 9.68 6.67 - - - “Cynorca FAM 73660 L P2 8.26 5.88 - - - occidentale” “Cynorca sociale” UCMP 66862 R P2 7.14 5.2 - - - “Cynorca sociale” UCMP 66862 L P2 7.32 5.3 - - - “Prosthennops” FAM 73696 R P2 9.42 6.61 - - - xiphidonticus Dyseohyus stirtoni FAM 73684 R P2 9.25 6.9 - - - Dyseohyus stirtoni FAM 73679 L P2 8.95 7.85 - - - Dyseohyus stirtoni FAM 73688 L P2 9.56 7.56 - - - Tayassu tajacu UF/MC 177228 R P2 8.23 6.72 - - - Tayassu tajacu UF/MC 177228 L P2 8.43 7.13 - - - “Cynorca” proterva USNM 26096 P2 8.3 6.2 - - - Hesperhyinae n. UF 234400 R P3 11.12 7.5 - - - gen. A & sp. B Hesperhyinae n. UF 234400 L P3 10.98 7.27 - - - gen. A & sp. B Dyseohyus FAM 73678 R P3 10.53 10.2 - - - Dyseohyus FAM 73678 L P3 10.6 10.6 - - - “Cynorca FAM 73660 R P3 8.18 7.3 - - - occidentale”

294

Table G-1. Continued. Taxon Cataloge number R Tooth BAPL BTWa BTWp BTW APLhy /L positio (mm) (mm) (mm) hyd d (mm) n (mm) "Cynorca FAM 73660 L P3 8.22 6.96 - - - occidentale" "Cynorca sociale" UCMP 66862 R P3 7.63 6.48 - - - "Cynorca sociale" UCMP 66862 L P3 7.84 6.47 - - - "Prosthennops" FAM 73696 R P3 10.01 8.26 - - - xiphidonticus "Prosthennops" FAM 73696 L P3 10.54 8.73 - - - xiphidonticus Dyseohyus stirtoni FAM 73684 R P3 9.38 8.01 - - - Dyseohyus stirtoni FAM 73679 R P3 10.2 9.77 - - - Dyseohyus stirtoni FAM 73679 L P3 9.67 10.03 - - - Dyseohyus stirtoni FAM 73688 L P3 9.97 9.44 - - - Tayassu tajacu UF/MC 177228 R P3 8.95 8.66 - - - Tayassu tajacu UF/MC 177228 L P3 9.29 9.09 - - - Pope's Creek USNM 336459 P3 8.3 7.7 - - - "Cynorca" proterva USNM 26096 P3 8.9 7.5 - - - Chesapeake Bay Hesperhyinae n. UF 234400 R P4 8.76 10.12 - - - gen. A & sp. B Hesperhyinae n. UF 234400 L P4 8.9 10.05 - - - gen. A & sp. B Dyseohyus FAM 73678 R P4 10.37 12.38 - - - Dyseohyus FAM 73678 L P4 10.57 12.53 - - - "Cynorca FAM 73660 R P4 8.03 9.07 - - - occidentale" "Cynorca FAM 73660 L P4 7.88 8.94 - - - occidentale" "Cynorca sociale" UCMP 66862 R P4 7.22 8.15 - - - "Cynorca sociale" UCMP 66862 L P4 7.28 8.3 - - - "Cynorca UCMP 68027 R P4 8.16 9.16 - - - occidentale" "Prosthennops" FAM 73696 R P4 10.46 11.79 - - - xiphidonticus "Prosthennops" FAM 73696 L P4 10.93 11.8 - - - xiphidonticus Dyseohyus stirtoni FAM 73684 R P4 8.79 10.45 - - - Dyseohyus stirtoni FAM 73679 R P4 9.9 11.46 - - - Dyseohyus FAM 73681 R P4 11.1 12.38 - - - Dyseohyus stirtoni FAM 73688 L P4 9.63 10.85 - - - Tayassu tajacu UF/MC 177228 R P4 9.98 10.82 - - -

295

Table G-1. Continued Taxon Cataloge number R Tooth BAPL BTWa BTWp BTW APLhy /L positio (mm) (mm) (mm) hyd d (mm) n (mm) Tayassu tajacu UF MC 177228 L P4 10.06 10.6 - - - Hesperhyinae n. UF 234400 R M1 10.73 11.64 - - - gen. A & sp. B Hesperhyinae n. UF 234400 L M1 10.72 11.24 - - - gen. A & sp. B Floridachoerus sp. UF 236934 L M1 17.71 18.65 - - - Hesperhyinae, gen. UF 281138 L M1 11.31 10.3 - - - B Dyseohyus FAM 73678 R M1 13.35 12.68 - - - Dyseohyus FAM 73678 L M1 13.28 12.95 - - - "Cynorca FAM 73660 R M1 11.17 11.49 - - - occidentale" (holotype) "Cynorca FAM 73660 L M1 10.77 11.39 - - - occidentale" (holotype) "Cynorca sociale" UCMP 66862 L M1 8.62 9.76 - - - "Cynorca UCMP 68027 R M1 10.64 10.83 - - - occidentale" "Prosthennops" FAM 73696 R M1 12.1 11.32 - - - xiphidonticus "Prosthennops" FAM 73696 L M1 12.2 11.6 - - - xiphidonticus Dyseohyus stirtoni FAM 73684 R M1 10.95 11.51 - - - Dyseohyus stirtoni FAM 73679 R M1 12.05 11.29 - - - Dyseohyus FAM 73681 R M1 13.23 12.35 - - - "Cynorca FAM 73665 R M1 9.93 10.55 - - - occidentale" "Cynorca FAM 73665 L M1 10.02 10.39 - - - occidentale" Dyseohyus stirtoni FAM 73688 L M1 10.64 11.35 - - - Cynorca proterva AMC 2895 L M1 10.88 10.22 - - - Tayassu tajacu UF/MC 177228 R M1 10.63 10.1 - - - Tayassu tajacu UF/MC 177228 L M1 10.88 10.16 - - - Pope's Creek USNM 336459 M1 9 9.4 - - - "Cynorca" proterva USNM 26096 M1 11.5 10.8 - - - Chesapeake Bay (W&H, 1987) Hesperhyinae n. UF 234400 R M2 11.74 12.9 - - - gen. A & sp. B Hesperhyinae n. UF 234400 L M2 11.63 13.03 - - - gen. A & sp. B Hesperhyinae n. UF 281140 L M2 na - - - gen. A & sp. A Hesperhyinae, gen. UF 234401 R M2 12.5 13.08 - - - B Dyseohyus FAM 73678 R M2 13.83 14.93 - - - Dyseohyus FAM 73678 L M2 14.69 14.91 - - -

296

Table G-1. Continued Taxon Cataloge number R Tooth BAPL BTWa BTWp BTW APLhy /L positio (mm) (mm) (mm) hyd d (mm) n (mm) "Cynorca FAM 73660 R M2 12.1 12.51 - - - occidentale" (holotype) "Cynorca FAM 73660 L M2 12.8 13.02 - - - occidentale" (holotype) "Cynorca sociale" UCMP 66862 R M2 10.56 10.75 - - - "Cynorca sociale" UCMP 66862 L M2 10.43 11.4 - - - "Cynorca UCMP 68027 R M2 11.96 12.33 - - - occidentale" "Prosthennops" FAM 73696 R M2 17.35 12.66 - - - xiphidonticus "Prosthennops" FAM 73696 L M2 15.19 13.18 - - - xiphidonticus Dyseohyus stirtoni FAM 73684 R M2 14.03 11.98 - - - Dyseohyus stirtoni FAM 73679 R M2 13.96 12.42 - - - Dyseohyus FAM 73681 R M2 16.17 14.84 - - - "Cynorca FAM 73665 R M2 11.13 11.12 - - - occidentale" Dyseohyus stirtoni FAM 73688 L M2 10.91 12.38 - - - Tayassu tajacu UF/MC 177228 R M2 12.46 11.87 - - - Tayassu tajacu UF/MC 177228 L M2 12.5 11.97 - - - "Cynorca" proterva USNM 23545 M2 12.1 11.5 - - - Chesapeake Bay (W&H, 1987) Dyseohyus FAM 73678 R M3 15.87 14.01 - - - Dyseohyus FAM 73678 L M3 15.62 13.91 - - - "Cynorca FAM 73660 R M3 10.76 9.1 - - - occidentale" (holotype) "Cynorca FAM 73660 L M3 10.96 9.45 - - - occidentale" (holotype) "Cynorca sociale" UCMP 66862 R M3 10.82 10.01 - - - "Cynorca sociale" UCMP 66862 L M3 10.58 9.79 - - - "Cynorca UCMP 68027 R M3 9.57 10.38 - - - occidentale" "Prosthennops" FAM 73696 R M3 17.02 12.26 - - - xiphidonticus "Prosthennops" FAM 73696 L M3 17.6 12.57 - - - xiphidonticus Dyseohyus stirtoni FAM 73684 R M3 14.62 11.05 - - - Dyseohyus stirtoni FAM 73679 R M3 13.87 12.18 - - - Dyseohyus FAM 73681 R M3 19.75 13.79 - - - Dyseohyus stirtoni FAM 73688 L M3 16.05 11.26 - - -

297

Table G-1. Continued Taxon Cataloge number R Tooth BAPL BTWa BTWp BTW APLhy /L positio (mm) (mm) (mm) hyd d (mm) n (mm) Cynorca proterva AMC 2896 L M3 11.34 9.15 - - - Hesperhyinae n. UF 234400 R M3 9.67 10.58 - - - gen. A & sp. B Hesperhyinae n. UF 234400 L M3 9.57 10.29 - - - gen. A & sp. B Floridachoerus V-5657 L M2 17.79 18.06 - - - olseni (Thomas Farm) Floridachoerus UF 212818 R M1 17.99 13.94 - - - olseni (Thomas Farm) "Cynorca sociale" AMC 2894 R Dp4 12.78 4.9 5.53 5.95 - Unknown taxon UF 166268(3) L Dp4 12.51 5.34 6.02 6.6 - cf Cynorca proterva FAM 73663 L Dp4 13.4 5.85 6.18 6.53 - Floridachoerus UF 264873 L p2 12.95 8.73 - - - olseni (Thomas Farm) Floridachoerus UF 262124 R p2 9.27 5.35 - - - olseni (Thomas Farm) Tayassu tajacu UF/MC 177228 R p2 8.7 4.55 - - - Pope's Creek USNM 336459 P2 7.7 5.9 - - - Ar4?/He (W&H, 1987) Pope's Creek USNM 336465 p2 8.1 3.9 - - - Ar4?/He (W&H, 1987) Pope's Creek USNM 205988 p2 8.7 4.3 - - - Ar4?/He (W&H, 1987) "Cynorca" proterva USNM 243996 p2 7.9 4.1 - - - "Cynorca" proterva USNM 241556 p2 8 4.3 - - - " Prosthennops USNM 25795 p2 8.8 5 - - - xiphidonticus" " Prosthennops p2 8.8 4.6 - - - xiphidonticus" "Prosthennops p2 8.7 4.9 - - - niobrarensis" Hesperhyinae n. UF 280424 L p3 9.9 5.6 - - - gen. A & sp. A Hesperhyinae, gen UF 281100 L p3 12.09 6.93 - - - B. et. sp. nov A

298

Table G-1. Continued Taxon Cataloge number R Tooth BAPL BTWa BTWp BTW APLhy /L positio (mm) (mm) (mm) hyd d (mm) n (mm) “Cynorca FAM 73660 R p3 8.73 4.68 - - - occidentale” “Cynorca USNM 22927 L p3 8.05 4.93 - - - occidentale” M. socialis UCMP 66861 R p3 6.99 4.09 - - - Floridachoerus UF 262124 R p3 13.11 7.94 - - - olseni (Thomas Farm) Floridachoerus UF 278452 L p3 12.1 8.89 - - - olseni (Thomas Farm) Tayassu tajacu UF/MC 177228 R p3 9.64 5.45 - - - Tayassu tajacu UF/MC 177228 L p3 9.37 5.24 - - - Pope’s Creek USNM 205988 p3 10.7 5.5 - - - Ar4?/He (W&H, 1987) “Cynorca” proterva USNM 243996 p3 8 4.3 - - - Chesapeake Bay (W&H, 1987) Dyseohyus stirtoni (W&H, 1987) Western R p3 10.1 6.1 - - - Nebraska/Colorado “ Prosthennops USNM 25795 p3 11.3 6.6 - - - xiphidonticus” Chesapeake Bay “ Prosthennops p3 10.3 6.6 - - - xiphidonticus” Nebraska “Prosthennops USNM 243740 p3 13.5 8 - - - niobrarensis” Chesapeake Bay “Prosthennops USNM 336464 p3 12.7 7.5 - - - niobrarensis” Chesapeake Bay “Prosthennops p3 11.4 7.1 - - - niobrarensis” Nebraska Hesperhyinae n. UF 244219 R p4 11.51 8.14 - - - gen. A & sp. A Hesperhyinae n. UF 280424 L p4 10.4 7.1 - - - gen. A & sp. A Hesperhyinae, gen. UF 245595 R p4 11.35 8.08 - - - B Hesperhyinae, gen. UF 281100 R p4 12.87 8.14 - - - B Hesperhyinae, gen. UF 281100 L p4 12.6 8.29 - - - B “Cynorca FAM 73660 R p4 9.23 5.27 - - - occidentale” “Cynorca USNM 22927 L p4 9.3 6.72 - - - occidentale”

299

Table G-1. Continued Taxon Cataloge number R Tooth BAPL BTWa BTWp BTW APLhy /L positio (mm) (mm) (mm) hyd d (mm) n (mm) "Cynorca FAM 73668 R p4 9.63 6.34 - - - occidentale" M. socialis UCMP 66863 L p4 9.29 5.46 - - - M. socialis UCMP 66861 R p4 8.6 5.63 - - - Floridachoerus UF 211500 R p4 14.58 10.21 - - - olseni (Thomas Farm) Floridachoerus UF 262124 R p4 14.73 10.37 - - - olseni (Thomas Farm) Tayassu tajacu UF/MC 177228 R p4 11.45 8.8 - - - Tayassu tajacu UF/MC 177228 L p4 11.65 8.91 - - - Pope's Creek USNM 336459 P4 8 9.8 - - - Ar4?/He (W&H, 1987) "Cynorca" proterva USNM 26096 P4 9.6 10.3 - - - Chesapeake Bay (W&H, 1987) "Cynorca" proterva USNM 299729 P4 9.3 10.4 - - - Chesapeake Bay (W&H, 1987) Dyseohyus stirtoni (W&H, 1987) Western P4 10.1 11.1 - - - Nebraska/Colorado Pope's Creek USNM 336465 p4 9.6 6.2 - - - Ar4?/He (W&H, 1987) Pope's Creek USNM 205988 p4 9.7 6.4 - - - Ar4?/He (W&H, 1987) "Cynorca" proterva USNM 243996 p4 10.9 7.3 - - - Chesapeake Bay (W&H, 1987) "Cynorca" proterva USNM 21835 p4 10.7 6.5 - - - Chesapeake Bay (W&H, 1987) "Cynorca FAM 73668 p4 9.9 7.1 - - - occidentale" Ravine Quarry Dyseohyus stirtoni (W&H, 1987) p4 11.5 8 - - -

" Prosthennops USNM 336462 p4 11.6 8.2 - - - xiphidonticus" Chesapeake Bay " Prosthennops USNM 20518 p4 13.2 8.7 - - - xiphidonticus" Chesapeake Bay

300

Table G-1. Continued Taxon Cataloge number R/L Tooth BAPL BTWa BTWp BTW positio (mm) (mm) (mm) hyd n (mm) “ Prosthennops USNM 214946 p4 13.4 9.3 xiphidonticus” “ Prosthennops p4 12.7 9 xiphidonticus” “Prosthennops USNM 243740 p4 15.8 11.3 niobrarensis” “Prosthennops USNM 336464 p4 16 10.7 niobrarensis” “Prosthennops USNM 336461 p4 15.9 11.3 niobrarensis” “Prosthennops p4 14 10.4 niobrarensis” Hesperhyinae n. UF 237885 L m1 10.48 7.7 gen. A & sp. B Hesperhyinae n. UF 237884 L m1 11.6 8.51 gen. A & sp. B Hesperhyinae n. UF 280424 L m1 10.65 8.6 gen. A & sp. A Hesperhyinae, gen. UF 281100 R m1 11.9 9.7 B Hesperhyinae, gen. UF 281100 L m1 12.01 9.84 B “Cynorca FAM 73660 R m1 10.81 8.01 occidentale” “Cynorca AMC 2894 L m1 10.12 6.78 occidentale” “Cynorca USNM 22927 L m1 10.7 9.49 occidentale” “Cynorca FAM 73668 R m1 9.58 7.73 occidentale” “Cynorca sociale” AMC 2894 R m1 10.5 7.17 Hesperhys?/Dyseo LSUMG V2267 L m1 15.25 12.63 hyus M. socialis UCMP 66863 L m1 9.62 6.82 Cynorca proterva AMC 2894 L m1 12.34 10.02 Unknown taxon UF 166268(3) L m1 10.57 7.9 M. socialis UCMP 66861 R m1 8.76 7.25 “Cynorca sociale” LSUMG-V2271 L m1 9.45 6.83 Simojovelhyus IMG 1902-6 L m1 8.28 5.6 pocitosense Cynorca sp. Buda UF 18498 R m1 10.84 6.65 L.F.

301

Table G-1. Continued Taxon Cataloge number R Tooth BAPL BTWa BTWp BTW /L positio (mm) (mm) (mm) hyd n (mm) Floridachoerus UF 211500 R m1 16.42 12.72 olseni (Thomas Farm) Tayassu tajacu UF/MC 177228 R m1 11.4 9.5 Tayassu tajacu UF/MC 177228 L m1 11.5 9.47 Pope's Creek USNM 336465 m1 11.1 7.9 Pope's Creek USNM 205988 m1 10.2 7.4 Ar4?/He (W&H, 1987) "Cynorca" proterva USNM 10320 m1 11.7 9 "Cynorca" proterva ANSP 11543d m1 11.5 8.7 Chesapeake Bay ( "Cynorca" FAM 73668 m1 10.6 8.4 occidentale Dyseohyus stirtoni m1 12.7 10.1 " Prosthennops USNM 336462 m1 12.8 10.3 xiphidonticus" " Prosthennops USNM 20518 m1 13.9 10.4 xiphidonticus" " Prosthennops USNM 214946 m1 14.7 11.3 xiphidonticus" " Prosthennops m1 13.5 10.8 xiphidonticus" "Prosthennops USNM 25715 m1 14.4 11.8 niobrarensis" "Prosthennops m1 15.4 11.3 niobrarensis" Hesperhyinae n. UF 237885 L m2 12.02 9.32 gen. A & sp. B Hesperhyinae n. UF 267038 R m2 10.39 11.48 gen. A & sp. A Hesperhyinae n. UF 246834 R m2 12.8 11.9 gen. A & sp. A Hesperhyinae n. UF 280424 L m2 13.21 10.69 gen. A & sp. A Hesperhyinae, gen. UF 281100 R m2 13.56 12.24 B Hesperhyinae, gen. UF 281100 L m2 13.3 12.22 B

302

Table G-1. Continued Taxon Cataloge number R Tooth BAPL BTWa BTWp BAPL BTW /L positio (mm) (mm) (mm) hyd hyd n (mm) (mm) "Cynorca FAM 73660 R m2 12.36 10.12 occidentale" "Cynorca USNM 22927 L m2 12.65 11.7 occidentale" "Cynorca FAM 73668 R m2 11.51 5.09 occidentale" Hesperhys? LSUMG V2267 L m2 17.82 14.45 M. socialis UCMP 66863 L m2 10.66 8.14 cf Cynorca proterva FAM 73663 L m2 11.82 9.06 M. socialis UCMP 66861 R m2 10.88 8.31 Simojovelhyus IMG 1902-6 L m2 8.78 6.94 pocitosense Floridachoerus UF 211500 R m2 17.66 14.3 olseni (Thomas Farm) Tayassu tajacu UF/MC 177228 R m2 12.82 11.02 Tayassu tajacu UF/MC 177228 L m2 13.57 10.72 Pope's Creek USNM 336465 m2 12.2 9.4 Pope's Creek USNM 205988 m2 11.1 8.8 "Cynorca" proterva USNM 18429 m2 12.1 10 "Cynorca" proterva USNM 10320 m2 13.2 11.2 "Cynorca FAM 73668 m2 11.5 9.9 occidentale" Dyseohyus stirtoni m2 14.6 12.4 " Prosthennops USNM 336462 m2 13.5 11.9 xiphidonticus" " Prosthennops USNM 20518 m2 15.4 12.3 xiphidonticus" " Prosthennops USNM 214946 m2 14.9 12.6 xiphidonticus"

303

Table G-1. Continued Taxon Cataloge R Tooth BAPL BTWa( BTWp BTW APL number /L position (mm) mm) (mm) hyd hyd (mm) (mm) "Prosthennops m2 15.2 12.7 xiphidonticus" "Prosthennops USNM 25715 m2 16.9 14.5 niobrarensis" "Prosthennops m2 17.3 13.5 niobrarensis" Hesperhyinae n. UF 280726 R m3 15.05 9.16 7.54 5.45 5.34 gen. A & sp. A Hesperhyinae n. UF 280424 L m3 14.7 8.99 7.21 5.3 5.99 gen. A & sp. A Hesperhyinae n. UF 281475 L m3 14.4 10.11 8.02 6.32 5.02 gen. A & sp. B Hesperhyinae, gen. UF 281100 R m3 15.7 11.16 8.09 5.33 4.32 B "Cynorca FAM 73660 R m3 13.2 8.89 7.1 4.53 5.22 occidentale" "Cynorca USNM 22927 L m3 13.99 10.06 8.17 6.47 5.16 occidentale" "Cynorca FAM 73668 R m3 13.05 8.29 7.48 5.35 5.84 occidentale" Hesperhys?/Dyseo LSUMG V2267 L m3 21.88 13.65 11.76 8.6 9.47 hyus M. socialis UCMP 66863 L m3 12.81 7.74 6.2 3.75 4.05 Simojovelhyus IMG 1902-6 L m3 10.67 6.31 5.25 3.84 4.79 pocitosense Floridachoerus UF 213037 R m3 22.3 14.4 12.37 7.95 9.88 olseni (Thomas Farm) Tayassu tajacu UF/MC 177228 R M3 12.57 11.27 Tayassu tajacu UF/MC 177228 L M3 12.65 11.22 Tayassu tajacu UF/MC 177228 R m3 17.19 10.35 10.54 8.89 6.75 Tayassu tajacu UF/MC 177228 L m3 17.13 10.82 10.51 8.12 7.17 Pope's Creek USNM 205988 m3 15.7 8.7 "Cynorca" proterva USNM 18429 m3 14.7 8.6 "Cynorca FAM 73668 m3 14 10.2 occidentale" Ravine Quarry Dyseohyus stirtoni m3 19.2 11.6 " Prosthennops USNM 336462 m3 20.8 12.2 xiphidonticus" Chesapeake Bay

304

Table G-1. Continued Taxon Cataloge number R Tooth BAPL BTWa BTWp BTW Taxon /L positio (mm) (mm) (mm) hyd n (mm) " Prosthennops USNM 20518 m3 22.8 11.3 xiphidonticus" Chesapeake Bay " Prosthennops USNM 214946 m3 22.2 12.9 xiphidonticus" Chesapeake Bay " Prosthennops m3 19.4 12.4 xiphidonticus" Nebraska "Prosthennops USNM 25715 m3 25.6 14 niobrarensis" Chesapeake Bay "Prosthennops m3 23.8 13.4 niobrarensis"

305

APPENDIX H DENTAL CHARACTERS USED IN THE PHYLOGENETIC ANALYSIS OF TAYASSUIDAE (CHAPTER 4)

(1) S1: Maxillopalatine labyrinth having a dorsal median sulcus: absent (0); present (1).

(2) S2: Postdental process of palate posterior to M3: absent (0); present (1).

(3) S3: Atrium on maxillopallatine labyrinth: absent (0); present (1).

(4) UD2: Upper M3 principal cusps not separated by accessory cusps: (0); separated

(1)

(5) UD3: Metaconule on upper P4: absent (0); present (1).

(6) UD4: Extension of cingula on upper P2-P3: restricted to the posterior part of the talon (0); reaching the lingual part of the protocone (1)

(7) UD7: Position of the cingula on P3: connecting posterolabial with the anterolingual sides of the crown (0); restricted to the posterior part of the crown (1); located posterolabially with or without cuspules (2).

(8) UD8: Lingual cingula on upper P3: absent (0); narrow (1)

(9) UD9: DP1: present (0); absent (1).

(10) UD11: M3/m3 relatively small than M2/m2: absent (0); present (1)..

(11) LD1: Paraconid of lower p4: present (0); absent (1)

(12) LD2: Lower p4 talonid cuspids: 1 (0); 2 or more (1)

(13) LD4: Posterolingual process of the protoconid on lower molars: absent to weak (0); distinct (1).

(14) LD5: Lower p2 and p3 talonid: narrow (0); broad (1).

(15) LD6: Paraconid on lower p3: absent (0); present (1).

(16) LD7: Paraconid on lower p2: absent (0); present (1)

306

(17) LD8: Posterolabial process of metaconid on lower p4: absent (0); present (1).

(18) LD9: Transverse valley on lower molars: continuos (0), partially blocked by entoconulid, weak posterolingual process of the protoconid (1).

(19) LD10: Number of cusps in lower p3 trigonid: 0(0); 1(1); more than one (2).

(20) LD 11: reduction of the m3 hypoconulid: unreduced, m3APL/m3hydAPL ratio < 3

(0); reduced, > or equal to 3.

(21) UD 12: cingulum on upper P4: strong and continuos, forming a continuous shelf around the crown but not present in the lingual side (0); discontinuos (1).

(22) LD 12: Occlusal outline of m3: elongate APL/TW ratio >1.5 (0); more square

(APL/TW ratio < or equal to 1.5 (1).

(23) S4: Symphysis: unfused (0); fused (1).

(24) S5: Relative depth of mandible below p4. Shallow, depth < p2-p4 APL (0), deep, > p2-p4 APL (1).

Abbreviations: APL, Anterior-Posterior Length, APLhyd, Anterior-Posterior Length

TW, transverse width, TWhyd, transverse width hypoconulid.

307

APPENDIX I CHARACTER-TAXON MATRIX USED IN THE PHYLOGENETIC ANALYSES OF EARLY MIOCENE TAYASSUIDAE (CHAPTER 4). SEE APPENDIX I FOR CHARACTER DESCRIPTIONS

1 1 2

1234567890 1234567890 1234

Perchoerus probus 0000000100 000??000?1 0000

Stuckyhyus siouxensis 0000000100 0001100010 1011

Floridachoerus olseni ?0?0010100 000???01?0 10??

Marshochoerus sociale 1100001100 00?000?101 0100

Hesperhyinae n. gen. A & sp. A ?????????1 1000001110 0000

Hesperhyinae n. gen. A & sp. B 1101001001 ??1????1?0 0000

"Cynorca" occidentale 11?11120?1 1110101111 0111

"Prosthenophs" xiphidonticus ??11112010 1110111121 0011

"Prosthennophs" niobarensis 1????????0 1110111120 ?011

Hesperhyinae n. gen. B & sp. A ?????????0 0111111111 ?111

1???1120?0 101110?111 01?0 Pope Creek tayassuid

Dyesohyus fricki 1111112110 1?10111110 0011

308

APPENDIX J EARLY MIOCENE UNGULATE OCCURRENCES FROM PANAMA

Table J-1. Early Miocene ungulate occurrences from Panama. Abbreviations: CF, Centenario Fauna; LNLF, Lirio Norte Local Fauna; YPA, site key for the fossiliferous localities along the Panama Canal area Order Family Genus CATALOG. # TOOTH YPA Assemblage POSITION Artiodactyla Protoceratidae Paratoceras UF 280625 LM1/ YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 275487 L/M3 YPA026 CF Artiodactyla Protoceratidae Paratoceras UF 280474 LM1/ YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 280867 L/P4 YPA072 CF Artiodactyla Protoceratidae Paratoceras UF 280466 RM3/ YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 280222 R/P3 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 280222 R/P4 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 280222 R/M1 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 280222 R/M2 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 236917 LM1/ YPA008 CF Artiodactyla Protoceratidae Paratoceras UF 275466 RDP3/ YPA026 CF Artiodactyla Protoceratidae Paratoceras UF 275466 RDP4/ YPA026 CF Artiodactyla Protoceratidae Paratoceras UF 275466 RM1/ YPA026 CF Artiodactyla Protoceratidae Paratoceras UF 271596 L/M3 YPA026 CF Artiodactyla Protoceratidae Paratoceras UF 275184 RM3/ YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 280223 R/M1 YPA084 CF Artiodactyla Protoceratidae Paratoceras UF 271616 RM2/ YPA050 CF Artiodactyla Protoceratidae Paratoceras UF 237877 RP3/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 237877 RP4/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 237877 RM1/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 237877 RM2/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 237877 RM3/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 236913 RP3/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 236913 RP4/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 236913 RM1/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 267123 L/P2 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267123 L/P3 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267123 L/P4 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267123 L/M1 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267123 L/M2 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267123 L/M3 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267124 L/P4 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267124 L/M1 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267124 L/M2 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267124 L/M3 YPA073 CF

309

Table J-1. Continued Order Family Genus CATALOG. # TOOTH YPA Assemblage POSITION Artiodactyla Protoceratidae Paratoceras UF 267125 L/M2 YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 280891 R/P3 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 280891 R/P4 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 280891 R/M1 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 280891 R/M2 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 280891 R/M3 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271180 LP4/ YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 223584 LP3/ YPA003 CF Artiodactyla Protoceratidae Paratoceras UF 223584 LM1/ YPA003 CF Artiodactyla Protoceratidae Paratoceras UF 271624 R/P2 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 271624 R/P3 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 271624 R/P4 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 271624 R/M1 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 271624 R/M2 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 271624 R/M3 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 237854 L/M1 YPA002 CF Artiodactyla Protoceratidae Paratoceras UF 237854 L/M2 YPA002 CF Artiodactyla Protoceratidae Paratoceras UF 237854 L/M3 YPA002 CF Artiodactyla Protoceratidae Paratoceras UF 223326 LM1/ USNM CF Artiodactyla Protoceratidae Paratoceras UF 223326 LM2/ USNM CF Artiodactyla Protoceratidae Paratoceras UF 223326 LM3/ USNM CF Artiodactyla Protoceratidae Paratoceras UF 275494 RP4/ YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 275494 RM1/ YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 275494 RM2/ YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 223094 L/P4 YPA002 CF Artiodactyla Protoceratidae Paratoceras UF 223094 L/M1 YPA002 CF Artiodactyla Protoceratidae Paratoceras UF 223094 L/M2 YPA002 CF Artiodactyla Protoceratidae Paratoceras UF 223094 L/M3 YPA002 CF Artiodactyla Protoceratidae Paratoceras UF 280829 L/P2 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 267125 L/P4 YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 267125 L/M1 YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 271180 LM1/ YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271180 LM2/ YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271181 R/P2 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 271181 R/P3 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 271181 R/P4 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 271181 R/M1 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 271181 R/M2 YPA073 CF

310

Table J-1. Continued Order Family Genus CATALOG. # TOOTH YPA Assemblage POSITION Artiodactyla Protoceratidae Paratoceras UF 271181 R/M3 YPA073 CF Artiodactyla Protoceratidae Paratoceras UF 280727 R/P4 YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 280727 R/M1 YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 280727 R/M2 YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 280727 R/M3 YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 280717 R/M1 YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 280717 R/M2 YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 280717 R/M3 YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 280762 LP4/ YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 280761 L/M1 YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 237878 L/M1 YPA015 CF Artiodactyla Protoceratidae Paratoceras UF 237878 L/M2 YPA015 CF Artiodactyla Protoceratidae Paratoceras UF 237878 L/M3 YPA015 CF Artiodactyla Protoceratidae Paratoceras UF 267081 L/M1 YPA016 CF Artiodactyla Protoceratidae Paratoceras UF 280439 L/M3 YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 223585 RM1/ YPA003 CF Artiodactyla Protoceratidae Paratoceras UF 223585 RM2/ YPA003 CF Artiodactyla Protoceratidae Paratoceras UF 223585 RM3/ YPA003 CF Artiodactyla Protoceratidae Paratoceras UF 223585 LM1/ YPA003 CF Artiodactyla Protoceratidae Paratoceras UF 223585 LM2/ YPA003 CF Artiodactyla Protoceratidae Paratoceras UF 223585 LM3/ YPA003 CF Artiodactyla Protoceratidae Paratoceras UF 271182 L/P1 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 L/P3 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 L/P4 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 L/M1 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 L/M2 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 L/M3 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 R/P1 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 R/P3 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 R/P4 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 223585 RP4/ YPA003 CF Artiodactyla Protoceratidae Paratoceras UF 271182 R/M1 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 R/M2 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271182 R/M3 YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 271625 R/P3 YPA063 CF Artiodactyla Protoceratidae Paratoceras UF 271625 R/P4 YPA063 CF Artiodactyla Protoceratidae Paratoceras UF 271625 R/M1 YPA063 CF Artiodactyla Protoceratidae Paratoceras UF 271625 R/M2 YPA063 CF

311

Table J-1. Continued Order Family Genus CATALOG. # TOOTH YPA Assemblage POSITION. Artiodactyla Protoceratidae Paratoceras UF 280094 L/M2 YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 275348 L/P2 YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 280176 R/P3 YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 275177 RP1/ YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 280212 RP4/ YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 271625 R/M3 YPA063 CF Artiodactyla Protoceratidae Paratoceras UF 271150 L/M3 YPA008 CF Artiodactyla Protoceratidae Paratoceras UF 236929 LM2/ YPA015 CF Artiodactyla Protoceratidae Paratoceras UF 237862 LM2/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 237864 RM3/ YPA009 CF Artiodactyla Protoceratidae Paratoceras UF 280221 LM3/ YPA060 CF Artiodactyla Protoceratidae Paratoceras UF 257203 RM2/ YPA026 CF Artiodactyla Protoceratidae Paratoceras UF 280910 RM3/ YPA086 CF Artiodactyla Protoceratidae Paratoceras UF 244213 R/M1 YPA024 LNLF Artiodactyla Protoceratidae Protoceras UF 280212 RP1/ YPA024 LNLF Artiodactyla Protoceratidae Protoceras UF 280212 RP2/ YPA024 LNLF Artiodactyla Protoceratidae Protoceras UF 280212 RP3/ YPA024 LNLF Artiodactyla Protoceratidae Protoceras UF 280212 RP4/ YPA024 LNLF Artiodactyla Protoceratidae Protoceras UF 280212 RM1/ YPA024 LNLF Artiodactyla Protoceratidae Protoceras UF 280212 LP1/ YPA024 LNLF Artiodactyla Protoceratidae Protoceras UF 280212 LM1/ YPA024 LNLF Artiodactyla Entelodontidae UF 281479 LM3/ YPA034 LNLF Artiodactyla Entelodontidae UF 280285 Cuboid YPA027 CF Artiodactyla Entelodontidae UF 280888 R/P2 YPA060 CF Artiodactyla Camelidae Aguascalientia UF 281038 L/M2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254121 L/M2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280017 L/M2 YPA080 LNLF Artiodactyla Camelidae Aguascalientia UF 246836 L/M2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246836 L/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 257198 L/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280821 R/M2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280821 R/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246828 R/P1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280831 L/C1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280745 LP1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280722 LP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280213 LP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246828 R/P2 YPA024 LNLF

312

Table J-1. Continued Order Family Genus CATALOG. TOOTH YPA Assemblage # POSITION Artiodactyla Camelidae Aguascalientia UF 281478 LC1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RM2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RM3/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280469 RP2/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 275168 L/M2 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 275168 L/M3 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 267055 R/P2 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 271622 R/M2 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 275195 R/M3 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280834 L/P3 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 281476 L/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246828 R/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246828 R/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280803 L/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254122 L/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280125 L/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281056 L/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280181 L/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280049 L/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/C1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/P1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/P2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280832 R/P2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275276 R/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246803 L/P3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 244316 L/P2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275273 L/P1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280877 R/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275182 R/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254123 L/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 267142 R/P3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275289 R/C1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/P3 YPA024 LNLF

313

Table J-1. Continued Order Family Genus CATALOG. # TOOTH YPA Assemblage POSITION Artiodactyla Camelidae Aguascalientia UF 246802 R/P1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/P2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/P3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246802 R/M2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 244184 RDP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280011 L/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254114 L/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280772 RDP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 259878 RDP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280447 DLP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275283 RDP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 267049 DL/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275267 DLP3/ YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 254119 RP4/ YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 280417 RP1/ YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 271626 LP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254118 L/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254120 L/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281036 R/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280575 L/P1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275419 L/P1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275174 R/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280980 L/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281039 L/P1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 244156 RDP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275175 DL/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280161 RDP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 246813 RDP4/ YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 271179 L/M1 YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 267194 R/P4 YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 267194 R/M1 YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 236931 LM2/ YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 281089 L/M1 YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 281089 L/M2 YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 281089 L/M3 YPA024 LNLF Artiodactyla Protoceratidae Paratoceras UF 271618 LP4/ YPA024 LNLF

314

Table J-1. Continued Order Family Genus CATALOG. # TOOTH YPA Assemblage POSITION Artiodactyla Camelidae Aguascalientia UF 280119 LP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275277 LP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280628 L/P2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280574 LP1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 244199 LP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 267047 LP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275388 LP1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281051 LM1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RM1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RM2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 LP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LP1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LM1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LM2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LM3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 RC1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 RP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 RP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 RM3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280897 LP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280897 LP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280897 LM1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281471 LP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281472 LM2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281473 RP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281470 R/P1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275457 RP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 267137 LC1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275445 LC1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280025 LP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RP1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281478 RP2/ YPA024 LNLF

315

Table J-1. Continued Order Family Genus CATALOG. TOOTH YPA Assemblage # POSITI ON Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280970 LP4/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 257197 RM2/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280214 RP1/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 275483 LP1/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280900 LP3/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 254127 L/P3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LM1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LM2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LM3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254125 RP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254125 RM1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280862 LM1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280862 LM2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 RC1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 RP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 RP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 RM3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 275169 LP1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254125 RM2/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280968 L/M1 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 271627 R/M2 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 281477 LM2/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 257196 R/M3 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 281472 LM2/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280452 RP1/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280729 RP4/ YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280937 RM3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280865 RP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280865 RP4/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280865 RM1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280865 RM3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280865 LP3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280862 RM1/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280862 RM2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280862 LP2/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 280862 LP4/ YPA024 LNLF

316

Table J-1. Continued Order Family Genus CATALOG. TOOTH YPA Assemblage # POSITION Artiodactyla Camelidae Aguascalientia UF 254125 RM3/ YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281059 R/P1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281059 R/P4 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281059 R/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281059 R/M2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 281059 R/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 244288 R/P2 YPA024 LNLF Artiodactyla Camelidae Floridatragulus sp. nov. UF 271595 R/M2 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 271595 R/M3 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 280029 L/P4 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 280029 L/M1 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 280737 R/M3 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 275446 R/P3 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 280091 L/P3 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 280991 LM3/ YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 280808 R/M1 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 280653 L/P2 YPA026 CF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280438 L/P4 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280492 R/P4 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280492 R/M1 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280492 R/M2 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280492 R/M3 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280492 L/M1 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280492 L/M2 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280492 L/M3 YPA024 LNLF Artiodactyla Camelidae Floridatragulinae n.gen&sp. UF 280664 L/M3 YPA024 LNLF Artiodactyla Camelidae Floridatragulus UF 271665 RDP4/ YPA009 CF Artiodactyla Camelidae Floridatragulus UF 281093 LM1/ YPA026 CF Artiodactyla Camelidae Floridatragulus UF 246853 RDP3/ YPA026 CF Artiodactyla Camelidae Floridatragulus UF 246853 RDP4/ YPA026 CF Artiodactyla Camelidae Floridatragulus UF 246853 RM1/ YPA026 CF Artiodactyla Camelidae Floridatragulus UF 280023 LM2/ YPA026 CF Artiodactyla Camelidae Floridatragulus UF 275486 LM3/ YPA026 CF Artiodactyla Camelidae Floridatragulus UF 280240 LM1/ YPA026 CF Artiodactyla Camelidae Floridatragulus UF 245482 LM3/ YPA019 CF Artiodactyla Camelidae Floridatragulus UF 267102 RM3/ YPA026 CF Artiodactyla Camelidae Floridatragulus UF 275485 RM3/ YPA026 CF Artiodactyla Camelidae Floridatragulus UF 271595 R/P4 YPA026 CF Artiodactyla Camelidae Floridatragulus UF 271595 R/M1 YPA026 CF

317

Table J-1. Continued Order Family Genus CATALOG. TOOTH YPA Assemblage # POSITION Artiodactyla Tayassuidae Hesperhyine, genus A. UF 234400 RM1/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, genus A. UF 234400 RM2/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, genus A. UF 234400 RM3/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, genus A. UF 234400 LP1/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, genus A. UF 234400 LP2/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 281100 L/P3 YPA086 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 281100 L/P4 YPA086 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 281100 L/M1 YPA086 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 281100 L/M2 YPA086 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 281100 L/M3 YPA086 CF Artiodactyla Tayassuidae Hesperhyine, genus A. UF 281138 LM1/ YPA072 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 280442 R/P2 YPA086 CF Artiodactyla Tayassuidae Hesperhyine, genus A. UF 245595 R/P4 YPA008 CF Artiodactyla Tayassuidae Floridachoerus UF 271646 LM2 YPA009 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 281100 R/P4 YPA086 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 281100 R/M1 YPA086 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 281100 R/M2 YPA086 CF Artiodactyla Tayassuidae Hesperhyine, genus B. UF 281100 R/M3 YPA086 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 245541 R/P4 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 245541 R/M1 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 245541 L/M2 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 246854 R/M3 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 257201 L/P3 YPA026 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 257201 L/P4 YPA037 CF Artiodactyla Camelidae Floridatragulus sp. nov. UF 245472 L/P4 YPA019 CF Artiodactyla Moschidae UF 280709 L/M1 YPA024 LNLF Artiodactyla Moschidae UF 275378 R/P3 YPA024 LNLF Artiodactyla Moschidae UF 267147 L/P4 YPA024 LNLF Artiodactyla Moschidae UF 280741 RM2/ YPA024 LNLF Artiodactyla Moschidae UF 280741 RM3/ YPA024 LNLF Artiodactyla Moschidae UF 280868 RP4/ YPA024 LNLF Artiodactyla Moschidae UF 280050 RP4/ YPA024 LNLF Artiodactyla Moschidae UF 280453 L/P4 YPA024 LNLF Artiodactyla Moschidae UF 275377 R/P2 YPA024 LNLF Artiodactyla Moschidae UF 280151 RM1/ YPA024 LNLF Artiodactyla Moschidae UF 280151 RM2/ YPA024 LNLF Artiodactyla Moschidae UF 280151 RM3/ YPA024 LNLF Artiodactyla Moschidae UF 275268 RP3/ YPA024 LNLF Artiodactyla Moschidae UF 280146 RP4/ YPA024 LNLF

318

Table J-1. Continued Order Family Genus CATALOG. TOOTH YPA Assembla # POSITION ge Artiodactyla Moschidae UF 280022 LM3/ YPA026 CF Artiodactyla Moschidae UF 280641 M(X) YPA086 CF Artiodactyla Anthracothere Arretotherium UF 244187 DL/P2 YPA024 LNLF Artiodactyla Anthracothere Arretotherium UF 244187 DL/P3 YPA024 LNLF Artiodactyla Anthracothere Arretotherium UF 244187 L/M1 YPA024 LNLF Artiodactyla Anthracothere Arretotherium UF 244187 L/M2 YPA024 LNLF Artiodactyla Anthracothere Arretotherium UF 244187 L/P1 YPA024 LNLF Artiodactyla Anthracothere Arretotherium UF 244174 LM1/ YPA024 LNLF Artiodactyla Anthracothere Arretotherium UF 244174 LM2/ YPA024 LNLF Artiodactyla Anthracothere Arretotherium UF 244174 LM3/ YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 275270 RDP4/ YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 267038 R/M2 YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 281140 LM2/ YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 244219 R/P4 YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 246834 R/M2 YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 280424 L/P3 YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 280424 L/P4 YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 280424 L/M1 YPA024 LNLF Artiodactyla Moschidae UF 267196 LM3/ YPA024 LNLF Artiodactyla Moschidae UF 275274 LM2/ YPA026 CF Artiodactyla Moschidae UF 275274 LM3/ YPA026 CF Artiodactyla Moschidae UF 275473 L/M1 YPA060 CF Artiodactyla Moschidae UF 257205 RM2/ YPA024 LNLF Artiodactyla Moschidae UF 257205 RM3/ YPA024 LNLF Artiodactyla Moschidae UF 275492 RM2/ YPA026 CF Artiodactyla Moschidae UF 280239 RM3/ YPA026 CF Artiodactyla Moschidae UF 280493 L/M1 YPA060 CF Artiodactyla Moschidae UF 275275 L/M1 YPA050 CF Artiodactyla Moschidae UF 280456 LM3/ YPA086 CF Artiodactyla Moschidae UF 275490 RM3/ YPA026 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 280424 L/M2 YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 280424 L/M3 YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 280726 L/M3 YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 267027 RDP3/ YPA024 LNLF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234400 RP1/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234400 RP2/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234400 LM2/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234400 RP3/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234400 RP4/ YPA016 CF

319

Table J-1. Continued Order Family Genus CATALOG. TOOTH YPA Assemblage # POSITION Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234400 LP3/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234400 LP4/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234400 LM1/ YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234400 LM3/ YPA016 CF Artiodactyla Tayassuidae Floridachoerus UF 236934 LM1/ YPA012 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 237885 L/M1 YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 237885 L/M2 YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 237884 L/M1 YPA016 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 236925 L/M1 YPA011 CF Artiodactyla Tayassuidae Hesperhyine, gen. A. UF 234401 RM2/ YPA003 CF Perissodactyla Equidae Parahippus sp. UF 267187 L/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280109 R/DP2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280109 R/DP3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280109 R/DP4. YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 267187 DL/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 267187 DL/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 267187 DL/P4 YPA024 LNLF Perissodactyla Equidae Anchitherium UF 280194 LP3/ YPA060 CF Perissodactyla Equidae Anchitherium UF 223327 LM1/ YPA002 CF Perissodactyla Equidae Anchitherium UF 223324 R/P2 YPA002 CF Perissodactyla Equidae Anchitherium UF 223324 R/P3 YPA002 CF Perissodactyla Equidae Anchitherium UF 223324 R/P4 YPA002 CF Perissodactyla Equidae Anchitherium UF 236937 MAXILLA YPA009 CF Perissodactyla Equidae Anchitherium UF 267122 DR/P2 YPA026 CF Perissodactyla Equidae Anchitherium UF 275330 L/P2 YPA071 CF Perissodactyla Equidae Archaeohippus UF 280694 L/M2 YPA060 CF Perissodactyla Equidae Archaeohippus UF 280019 R/P3 YPA071 CF Perissodactyla Equidae Archaeohippus UF 280619 LM3/ YPA026 CF Perissodactyla Equidae Archaeohippus UF 236918 LP2/ YPA008 CF Perissodactyla Equidae Archaeohippus UF 280579 DLP3/ YPA026 CF Perissodactyla Equidae Archaeohippus UF 271178 DRP2/ YPA026 CF Perissodactyla Equidae Archaeohippus UF 280499 DLP4/ YPA026 CF Perissodactyla Equidae Archaeohippus UF 245470 RP2/ YPA019 CF Perissodactyla Equidae Archaeohippus UF 280254 R/P4 YPA026 CF Perissodactyla Equidae Archaeohippus UF 280020 RM3/ YPA079 CF Perissodactyla Equidae Archaeohippus UF 280441 RM3/ YPA026 CF Perissodactyla Calichotheriid UF 280165 L/M2 YPA024 LNLF ae Perissodactyla Rhinoceratid UF 275402 R/P2 YPA009 CF ae

320

Table J-1 Continued Order Family Genus CATALOG. # TOOTH POSITION YPA Assemblage Perissodactyla Equidae Parahippus sp. UF 280500 L/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280500 L/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280500 L/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280500 L/M2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280500 L/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 142115 L/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 142115 L/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 142115 L/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 142115 L/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 142115 L/M2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 142115 L/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280501 RP2/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280501 RP3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280501 RP4/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280501 RM1/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280501 RM2/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 RP2/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 RP3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 RP4/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 RM1/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 RM2/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 RM3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 R/P1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 R/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 R/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 R/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 R/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 R/M2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 R/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 L/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 L/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 L/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 L/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 L/M2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280276 L/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246831 L/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246835 R/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246835 R/P4 YPA024 LNLF

321

Table J-1. Continued Order Family Genus CATALOG. # TOOTH POSITION. YPA Assemblage Perissodactyla Equidae Parahippus sp. UF 280770 L/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280177 R/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280114 L/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280068 RDP4/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280244 R/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280015 DR/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280778 R/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280046 R/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 267141 R/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246832 L/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 267146 L/M2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246826 R/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246827 R/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 244303 LM3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280016 LP3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280875 LM3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280858 LM3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280180 LP2/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280081 DLP4/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 275489 LM1/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280059 LP2/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 245599 RP3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 244289 LP2/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280961 RP2/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246830 RM3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 267139 LM3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 245603 RP2/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 267197 LP4/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 267130 LM3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 267138 RM1/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 275472 R/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 244185 LP3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246824 L/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246824 L/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246824 L/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246824 L/M2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 246824 L/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280999 RM3/ YPA024 LNLF

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Table J-1. Continued Order Family Genus CATALOG. # TOOTH YPA Assemblage POSITION. Perissodactyla Equidae Parahippus sp. UF 280924 R/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280639 L/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280110 R/M2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 245606 L/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 245606 L/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 275390 R/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280771 R/M2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280095 DL/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280117 R/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280432 DL/P4 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280056 R/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280113 R/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280063 L/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280048 L/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 244319 L/M1 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280112 R/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 271175 RDP4/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 244212 L/M3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280062 L/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280057 L/P2 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280430 RP4/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280006 LP3/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280006 LP4/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280006 LM1/ YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 281034 R/M2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 L/P2 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 L/P3 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 L/P4 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 L/M1 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 L/M2 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 L/M3 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 R/P4 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 R/M1 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 R/M2 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 236939 R/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254113 R/M3 YPA034 LNLF Artiodactyla Camelidae Aguascalientia UF 236939 R/P3 YPA024 LNLF Perissodactyla Equidae Parahippus sp. UF 280774 RM1/ YPA024 LNLF

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Table J-1. Continued Order Family Genus CATALOG. # TOOTH YPA Assemblage POSITION. Artiodactyla Camelidae Aguascalientia UF 236939 R/M1 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 236939 R/M2 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 236939 R/M3 YPA024 LNLF Artiodactyla Camelidae Aguascalientia UF 254129 L/P2 YPA024 LNLF Perissodactyla Equidae Archaeohippus UF 223329 RM1/ YPA002 CF Artiodactyla Merychoidodontinae Sp.1 UF 275235 LM2/ YPA060 CF Artiodactyla Merychoidodontinae Sp.2 UF 223579 LM3/ YPA005 CF Artiodactyla Merychoidodontinae Sp.1 UF 236843 MX/ YPA005 CF Artiodactyla Merychoidodontinae Sp.1 UF 223325 L/M2 YPA002 CF Artiodactyla Merychoidodontinae Sp.1 UF 223325 L/M3 YPA002 CF Artiodactyla Merychoidodontinae Sp.1 UF 223320 R/P4 YPA002 CF Artiodactyla Merychoidodontinae Sp.1 UF 223320 R/M1 YPA002 CF Artiodactyla Merychoidodontinae Sp.1 UF 223320 R/M2 YPA002 CF Artiodactyla Merychoidodontinae Sp.1 UF 223320 R/M3 YPA002 CF Perissodactyla Rhinoceratidae UF 275335 R/P2 YPA060 CF Perissodactyla Rhinoceratidae UF 223330 L/P2 YPA002 CF Perissodactyla Rhinoceratidae UF 275187 R/M1 YPA050 CF

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APPENDIX K EARLY MIOCENE UNGULATE SPECIES FROM PANAMA

Table K-1. Relative abundance of artiodactyls from Panama expressed as Minimun Number of Individuals (MNI) calculated on the occurrence of partial dentitions. Site Key Faunal assemblage Arretotheri Protocer Paratocer P. P. um sp. as sp. as sp. coate orari si us

YPA002 Centenario Fauna 0 0 0 2 0 YPA003 Centenario Fauna 0 0 0 2 0 YPA005 Centenario Fauna 0 0 0 0 0 YPA008 Centenario Fauna 0 0 0 1 0 YPA009 Centenario Fauna 0 0 0 2 0 YPA011 Centenario Fauna 0 0 0 0 0 YPA012 Centenario Fauna 0 0 0 0 0 YPA015 Centenario Fauna 0 0 0 0 1 YPA016 Centenario Fauna 0 0 0 0 1 YPA019 Centenario Fauna 0 0 0 0 0 YPA026 Centenario Fauna 0 0 0 3 0 YPA027 Centenario Fauna 0 0 0 0 0 YPA037 Centenario Fauna 0 0 0 0 0 YPA050 Centenario Fauna 0 0 0 1 0 YPA060 Centenario Fauna 0 0 0 3 0 YPA063 Centenario Fauna 0 0 0 0 1 YPA071 Centenario Fauna 0 0 0 0 0 YPA072 Centenario Fauna 0 0 0 1 0 YPA073 Centenario Fauna 0 0 0 2 0 YPA079 Centenario Fauna 0 0 0 0 0 YPA081 Centenario Fauna 0 0 0 0 0 YPA084 Centenario Fauna 0 0 0 0 1 YPA086 Centenario Fauna 0 0 0 2 0

Total MNI Centenario Fauna 0 0 0 19 4 Relative abundance (% per 0.00 0.00 0.00 24.68 5.19 assemblage) Relative abundance (% Ungulates 0.00 0.00 0.00 14.96 3.15 Panama)

325

Table K-1. Continued Site Key Faunal assemblage Floridatra A. A. Floridatr Calichotheriidae gulinae panama minuta agulus n. gen & ensis sp. nov sp. YPA002 Centenario Fauna 0 0 0 0 0 YPA003 Centenario Fauna 0 0 0 0 0 YPA005 Centenario Fauna 0 0 0 0 0 YPA008 Centenario Fauna 0 0 0 0 0 YPA009 Centenario Fauna 0 0 0 1 0 YPA011 Centenario Fauna 0 0 0 0 0 YPA012 Centenario Fauna 0 0 0 0 0 YPA015 Centenario Fauna 0 0 0 0 0 YPA016 Centenario Fauna 0 0 0 0 0 YPA019 Centenario Fauna 0 0 0 1 0 YPA026 Centenario Fauna 0 0 0 4 0 YPA027 Centenario Fauna 0 0 0 0 0 YPA037 Centenario Fauna 0 0 0 1 0 YPA050 Centenario Fauna 0 0 0 0 0 YPA060 Centenario Fauna 0 0 0 0 0 YPA063 Centenario Fauna 0 0 0 0 0 YPA071 Centenario Fauna 0 0 0 0 0 YPA072 Centenario Fauna 0 0 0 0 0 YPA073 Centenario Fauna 0 0 0 0 0 YPA079 Centenario Fauna 0 0 0 0 0 YPA081 Centenario Fauna 0 0 0 0 0 YPA084 Centenario Fauna 0 0 0 0 0 YPA086 Centenario Fauna 0 0 0 0 0

Total MNI Centenario 0 0 0 7 0 Fauna Relative abundance 0.00 0.00 0.00 9.09 0.00 (% per assemblage) Relative abundance 0.00 0.00 0.00 5.51 0.00 (% Ungulates Panama)

326

Appendix K-1. Continued Site Key Faunal assemblage "Parahip Anchither Archaeohi Hesperhyina Hesperhyina pus" sp. ium ppus sp. e n. gen. A e n. gen. B & sp. B & sp. A

YPA002 Centenario Fauna 0 1 1 0 0 YPA003 Centenario Fauna 0 0 0 0 1 YPA005 Centenario Fauna 0 0 0 0 0 YPA008 Centenario Fauna 0 0 1 0 1 YPA009 Centenario Fauna 0 1 0 0 0 YPA011 Centenario Fauna 0 0 0 0 1 YPA012 Centenario Fauna 0 0 0 0 0 YPA015 Centenario Fauna 0 0 0 0 0 YPA016 Centenario Fauna 0 0 0 3 0 YPA019 Centenario Fauna 0 0 1 0 0 YPA026 Centenario Fauna 0 1 4 0 0 YPA027 Centenario Fauna 0 0 0 0 0 YPA037 Centenario Fauna 0 0 0 0 0 YPA050 Centenario Fauna 0 0 0 0 0 YPA060 Centenario Fauna 0 1 1 0 0 YPA063 Centenario Fauna 0 0 0 0 0 YPA071 Centenario Fauna 0 1 1 0 0 YPA072 Centenario Fauna 0 0 0 0 1 YPA073 Centenario Fauna 0 0 0 0 0 YPA079 Centenario Fauna 0 0 1 0 0 YPA081 Centenario Fauna 0 0 0 0 0 YPA084 Centenario Fauna 0 0 0 0 0 YPA086 Centenario Fauna 0 0 0 0 1

Total MNI Centenario 0 5 10 3 5 Fauna Relative abundance 0.00 6.49 12.99 3.90 6.49 (% per assemblage) Relative abundance 0.00 3.94 7.87 2.36 3.94 (% Ungulates Panama)

327

Appendix K-1. Continued Site Key Faunal assemblage Hesperhyina Floridac Moschidae Entelodo Merycho e n. gen. A hoerus inc sedis ntidae choerus & sp. A. sp. sp.

YPA002 Centenario Fauna 0 0 0 0 1 YPA003 Centenario Fauna 0 0 0 0 0 YPA005 Centenario Fauna 0 0 0 0 1 YPA008 Centenario Fauna 0 0 0 0 0 YPA009 Centenario Fauna 0 1 1 0 0 YPA011 Centenario Fauna 0 0 0 0 0 YPA012 Centenario Fauna 0 1 0 0 0 YPA015 Centenario Fauna 0 0 0 0 0 YPA016 Centenario Fauna 0 0 0 0 0 YPA019 Centenario Fauna 0 0 0 0 0 YPA026 Centenario Fauna 0 0 2 0 0 YPA027 Centenario Fauna 0 0 0 1 0 YPA037 Centenario Fauna 0 0 0 0 0 YPA050 Centenario Fauna 0 0 1 0 0 YPA060 Centenario Fauna 0 0 2 1 1 YPA063 Centenario Fauna 0 0 0 0 0 YPA071 Centenario Fauna 0 0 0 0 0 YPA072 Centenario Fauna 0 0 0 0 0 YPA073 Centenario Fauna 0 0 0 0 0 YPA079 Centenario Fauna 0 0 0 0 0 YPA081 Centenario Fauna 0 0 0 0 0 YPA084 Centenario Fauna 0 0 0 0 0 YPA086 Centenario Fauna 0 0 1 0 0

Total MNI Centenario Fauna 0 2 7 2 3 Relative abundance (% per 0.00 2.60 9.09 2.60 3.90 assemblage) Relative abundance (% 0.00 1.57 5.51 1.57 2.36 Ungulates Panama)

328

Appendix K-1. Continued Site Key Faunal assemblage Merychoidodontinae Rhinoceratidae MNI per site key 2

YPA002 Centenario Fauna 0 1 6 YPA003 Centenario Fauna 0 0 3 YPA005 Centenario Fauna 1 0 2 YPA008 Centenario Fauna 0 0 3 YPA009 Centenario Fauna 0 2 8 YPA011 Centenario Fauna 0 1 2 YPA012 Centenario Fauna 0 0 1 YPA015 Centenario Fauna 0 0 1 YPA016 Centenario Fauna 0 0 4 YPA019 Centenario Fauna 0 0 2 YPA026 Centenario Fauna 0 0 14 YPA027 Centenario Fauna 0 0 1 YPA037 Centenario Fauna 0 0 1 YPA050 Centenario Fauna 0 1 3 YPA060 Centenario Fauna 0 2 11 YPA063 Centenario Fauna 0 0 1 YPA071 Centenario Fauna 0 0 2 YPA072 Centenario Fauna 0 0 2 YPA073 Centenario Fauna 0 0 2 YPA079 Centenario Fauna 0 0 1 YPA081 Centenario Fauna 0 1 1 YPA084 Centenario Fauna 0 0 1 YPA086 Centenario Fauna 0 1 5

Total MNI Centenario Fauna 1 9 77 Relative abundance (% per 1.30 11.69 assemblage) Relative abundance (% 0.79 7.09 Ungulates Panama)

329

Appendix K-1. Continued Taxon YPA08 YPA03 YPA02 Total Relative Relative 0 6 4 MNI abundance (% abundance (% per assemblage) Ungulates) Arretotherium sp. 0 0 2 2 4.00 1.57 Protoceras sp. 0 0 1 1 2.00 0.79 Paratoceras sp. (LNLF) 0 0 2 2 4.00 1.57 P. coatesi 0 0 0 0 0.00 0.00 P. orarius 0 0 0 0 0.00 0.00 Floridatragulinae n. gen 0 0 4 4 8.00 3.15 & sp. A. panamaensis 1 0 13 14 28.00 11.02 A. minuta 0 1 0 1 2.00 0.79 Floridatragulus sp. nov 0 0 0 0 0.00 0.00 Calichotheriidae 0 0 1 1 2.00 0.79 "Parahippus" sp. 0 0 15 15 30.00 11.81 Anchitherium 0 0 0 0 0.00 0.00 Archaeohippus sp. 0 0 0 0 0.00 0.00 Hesperhyinae Genus A, 0 0 0 0 0.00 0.00 sp. B Hesperhyinae Genus B 0 0 0 0 0.00 0.00 Hesperhyinae Genus A, 0 0 3 3 6.00 2.36 sp. A Floridachoerus sp. 0 0 0 0 0.00 0.00 Moschidae inc sedis 0 0 5 5 10.00 3.94 Entelodontidae 0 1 0 1 2.00 0.79 Merychochoerus sp. 0 0 0 0 0.00 0.00 Merychoidodontinae 2 0 0 0 0 0.00 0.00 Rhinoceratidae 0 0 1 1 2.00 0.79

MNI per site key 1 2 47 50

330

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BIOGRAPHICAL SKETCH

Aldo Rincón is a Colombian geologist. He has worked with fossil vertebrates since

2007; first in Colombia, where he did intense fieldwork among a variety of localities and fossil groups until he decided to focus his research on fossil mammals. His Bachelor degree was obtained from the National University of Colombia (Bogota) in 2005. After two years as field geologist and researcher at his institution, he moved to Panama to do an internship at the Smithsonian Tropical Research Institute (STRI). Once he finished his internship, he moved to Florida where he attended to graduate school at the

Department of Geological Sciences. He obtained his MSc degree in 2011 and his PhD in 2016. His research focuses on understanding the paleobiogeographical and evolutionary history of tropical vertebrate (mainly mammals) during the Cenozoic. He is also doing related fieldwork in the terrestrial Paleocene and Eocene fossiliferous localities in northern central Colombia investigating the relation between tectonic change and paleobiogeography.

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