Evolution and Classification of the Pocket Gophers of the Subfamily Geomyinae

The fossil record of the subfamily Geomyinae begins in the early Miocene of western North America. No geomyids have been recovered from beds of the late Miocene age. Beginning w...

In _Dikkomys_, the anterior and posterior column first unite near their mid-points in the first stages of wear thus producing a figure-8 shaped (H-shaped) occlusal pattern in th...

Three extinct species of _Thomomys_, all referable to the subgenus _Thomomys_, have been described. _Thomomys microdon_ Sinclair (1905:146), based on the rostral portion of a sk...

While the Entoptychinae probably evolved in response to the Arcto-tertiary flora, the late Tertiary geomyines probably evolved in response to the Madro-tertiary geoflora on the...

The genus _Pappogeomys_, as it is conceived of in this study, is comprised of two subgenera; one, _Pappogeomys_, is generalized and primitive, and the other, _Cratogeomys_, is s...

The masseteric ridge of the mandible is well developed. In the late Pliocene species _Z. persimilis_ and _Z. minor_ the mental foramen is directly beneath the anterior extension...

The evidence points to a major divergence of the geomyines that lived in the latest Miocene or the early Pliocene (probably the latter) and that gave rise to the two modern line...

_Chronologic and geographic range._--Known from late Pliocene (early Blancan) to Recent. Known primarily from western North America from southern Canada south to Central México...

Hibbard proposed the generic name _Parageomys_ (1944:55), but later regarded it as a subgenus of _Geomys_ (1956:182) that includes those species retaining continuous enamel band...

_Description._--Skull dolichocephalic in varying degree (overlapping subgenera _Orthogeomys_ and _Heterogeomys_ in this respect); mandibles elongated, not spreading far laterall...

CLASSIFICATION 512 Family Geomyidae 512 Subfamily *Entoptychinae 513 Genus *_Pleurolicus_ 514 Genus *_Gregorymys_ 514 Genus *_Grangerimus_ 514 Genus *_Entoptychus_ 514 Subfamily...

The genus _Pappogeomys_ is not known from Pleistocene deposits older than the Wisconsin glaciation, but a pre-Pleistocene occurrence in the Benson beds of Arizona (see discussio...

1839. Observations on the Rodentia, with a view to point out the groups, as indicated by the structure of the crania, in this order of mammals. Mag. Nat. Hist., new series, 3:90...