Entoptychine gophers are a species-rich subfamily of the Geomyidae from the Oligo-Miocene known from countless teeth, numerous jaws, and rare skulls and skeletons. Because of this rich fossil record, entoptychine gophers have greatly contributed to our understanding of the biostratigraphy, biogeography, and paleoecology of fossil deposits of the western United States. Nonetheless, there is currently no phylogenetic framework for the subfamily. We describe four new species of entoptychines from the Arikareean-aged Cabbage Patch beds of Montana, including three species of the genus Pleurolicus (P. gwinni, P. nelsoni, and P. rensbergeri) and one species of Gregorymys (G. tavenneri) and include these taxa into the first phylogenetic analysis of Entoptychinae to include all species within PleurolicusCope, 1878, GregorymysWood, 1936, and ZiamysGawne, 1975, as well as a species of the genus EntoptychusCope, 1878. We recover a paraphyletic Pleurolicus at the base of the tree. Ziamys is a monophyletic genus, sister taxon to the clade formed by the genera Entoptychus and Gregorymys. Within Pleurolicus, the species strictly from the Great Plains form a clade. Gregorymys is divided into two major clades, one that includes the southern species G. riograndensisStevens, 1977, and G. veloxikua Jiménez-Hidalgo et al., 2018, as well as G. riggsiWood, 1936, and G. tavenneri and one including all other species from the northern Great Plains and Rocky Mountains. Gregorymys kayiWood, 1950, a poorly known outlier species of the genus is sister to the Entoptychus species included in our analysis. Our findings suggest a complicated evolutionary history for the Entoptychinae, but also offer the opportunity for fruitful future analyses of evolutionary ecology.
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31 July 2020
New Gophers (Rodentia: Geomyidae) from the Cabbage Patch Beds of Montana (Renova Formation) and the Phylogenetic Relationships Within Entoptychinae
Jonathan J.M. Calede,
Donald L. Rasmussen
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Annals of Carnegie Museum
Vol. 86 • No. 2
July 2020
Vol. 86 • No. 2
July 2020
Arikareean
continuous characters
Entoptychus
Gregorymys
John Day Formation
Oligocene
Pleurolicus