1895. Pappogeomys Merriam, N. Amer. Fauna, 8:145, January 31.
Type.—Geomys bulleri Thomas, 1892, from near Talpa, west slope Sierra de Mascota, 8500 ft. (actually about 5000 ft.), Jalisco.
Chronologic range.—Late Pliocene (Benson local fauna, Arizona) to Recent, but no specimens known from Pleistocene.
Description.—Small, approximately same size as small subspecies of Thomomys umbrinus but forefeet larger and claws longer; skull of generalized shape, broad, relatively short, smoothly rounded, not especially compressed dorso-ventrally; zygomatic breadth great but not exceeding mastoid breadth; zygomata relatively slender for geomyid and lacking platelike expansions at lateral angles; rostrum relatively narrow; sagittal crest lacking, owing to impressions of temporal muscles remaining separated; angular process of mandible not especially elongated; enamel plates extending completely across posterior wall of M1 and M2, except in one species, P. alcorni, where posterior plate of M1 remains only on lingual fourth of posterior wall (remainder of plate lacking); with wear, plates sometimes exceptionally thin completely across posterior face of M2 and especially M1 in a few individuals of P. bulleri much as Paulson (1961:138-139) describes in extinct Geomys tobinensis; one or both plates rarely disappear in final stages of attrition in old individuals resulting in same dental pattern found in Cratogeomys; M1 and M2 retaining enamel plate on anterior wall throughout life; M3 usually subtriangular in cross-section but sometimes suborbiculate or ovoid, crown slightly bilophodont owing to shallowness of labial re-entrant angle in modern species; posterior loph of M3 not especially elongated and crown not significantly longer than wide; both lateral enamel plates of M3 usually well developed and approximately equal in length, occasionally plates reduced in length and rarely one or both plates are lost with wear in old individuals; patch of whitish or buffy hairs surrounding nose of most individuals.
The primitive character of the lower dentition, as described in the species account above, suggest that Cratogeomys [= Pappogeomys] bensoni Gidley should be referred to the subgenus Pappogeomys rather than Cratogeomys. Only the upper dentition would make positive identification possible; however, reference to the subgenus Pappogeomys seems to be the best arrangement at this time.
Referred species.—Three (one extinct):
*Pappogeomys bensoni (Gidley), 1922. U. S. Geol. Surv. Prof. Papers, 131:123. Type from Benson local fauna (late Pliocene), Cochise County, Arizona.