New floridatragulines (Mammalia, Camelidae) from the early Miocene Las Cascadas Formation, Panama

ABSTRACT

Early Miocene floridatraguline camels are characterized by having an elongate snout, shallow and narrow symphysial area, and relatively primitive dentitions. Their fossil record is restricted to subtropical assemblages including the Hemingfordian Thomas Farm Local Fauna (L. F.) in Florida, the Zoyotal L. F. in Mexico, and the Arikareean Castolon L. F. in Texas. Here we describe the first floridatraguline camels from the early Miocene Las Cascadas Formation, Panama Canal area, Central America. We describe two new species that are similar to Aguascalientia wilsoni from the Zoyotal L. F. in having (1) a primitive lower dental formula, (2) brachydont teeth, (3) an unusually elongate jaw with caniniform c1 and p1 that are well separated by a diastema, (4) a long and narrow mandibular symphysis, (5) lower molars with small intercolumnar pillars, (6) an m3 hypoconulid divided by lingual and labial selenes, and (7) no diastema between p2 and p3. Aguascalientia panamaensis, sp. nov., and Aguascalientia minuta, sp. nov., are represented by partial lower dentitions and isolated upper molars. Both new species are distinct from A. wilsoni in having (1) p1 and c1 similar in size, (2) less inflected paraconids on lower premolars, and (3) less reduced premolars. Interpreted primitive characters are similar to a small, unnamed camel from the earliest Miocene Buda L. F. of Florida (middle late Arikareean NALMA). The Las Cascadas fossil assemblage probably constitutes a distinctive Arikareean (Ar3–Ar4) faunal province characterized by the arrival of northern immigrants into a small continental basin connected with North American continental terrains.

ACKNOWLEDGMENTS

We thank J. Bourque, who prepared the specimens in the laboratory; T. Rowe and L. K. Murray (TMM) for access to relevant research collections; C. Montes, M. Vallejo, and F. Moreno (STRI) who helped in the collection of the specimens; and R. Hulbert Jr. for help with anatomical terminology and taxonomic nomenclature. C. Manz, L. Oviedo, E. Woodruff, F. Herrera, P. Morse, A. Hastings, J. Pardo, and J. Serrano read an earlier version of the manuscript and made helpful comments for its improvement. We thank the Panama Canal Authority (ACP) for assess to relevant fossil sites. 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; STRI-Tupper Paleontological Fund; STRI-Panama Canal Authority Fund; and Ricardo Perez Toyota, Panama. This is a UF Contribution to Paleobiology number 641.

Handling editor: Jessica Theodor