New Mexico Geological Society Annual Spring Meeting & Ft. Stanton Cave Conference — Abstracts

A skull and associated postcrania found in the Paleocene Nacimiento Formation are the first specimensof the eubaenine turtle Goleremys mckennai identified east of the Sierra Nevada Mountains. The skull of NMMNH (New Mexico Museum of Natural History) P-9067 is from the Torrejonian, in the West flank of Torrejon Wash. It matches the diagnostic characters listed by Hutchison (2004) for the taxon, including the moiety or divide between the triturating surfaces growing larger posteriorly, a short unconstructed rostrum and the jugal restricted to the posterior of the orbit. Conversely, the nasal may be slightly separated from the maxilla or just barely touching, and this is likely individual variation. In addition, NMMNH P-9067 has the small triangular parietals added to the diagnosis in Joyce and Lyson’s revision of the taxon. The right mandible is superficially similar to that of Neurankylus torrejonensis, but shorter and with an anteriorly widening triturating surface. The associated postcrania give the first look at this animal’s forelimbs and carapace. The carapace is thick and fully fused, indicating this was an adult individual. This animal is likely aquatic as other baenids are inferred to be. Interestingly, the posteriorly widening moiety resembles those of the extant Trachemys scripta, which contribute to the flexible diet of these turtles. Thus, we infer that Goleremys may have had a similarly diverse tolerance for varied food sources. This could contribute to its wide geographic range as it is the only baenid known west of the Sierra Nevada Mountains.

References:

1. Hutchison, J. H. 2004. A new eubaenine, Goleremys mckennai, gen. et sp. n.,(Baenidae: Testudines) from the Paleocene of California.Bulletin of the Carnegie Museum of Natural History 36:91–96.
2. Joyce, W. G. and Lyson, T. R., 2015, A review of the fossil record of turtles of the clade Baenidae. Bulletin of the Peabody Museum of Natural History, v. 56(2), p. 147-183.