|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Mammalia - Rodentia - Geomyidae
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|E. D. Cope 1878||
Specif. Char. This species resembles those of the allied genus Entop- tychus in many respects. The superciliary borders are thickened upwards, forming two ridges, which enclose a groove between them which is more pronounced than in the Entoptychus cavifrons. The muzzle is plane above and considerably wider than the interorbital space. The base of the ma- lar is thin and oblique, and the foramen infraorbitale exterius is well in advance of the molar teeth and at the anterior part of the maxillary bone. A groove passes backwards from its inferior border, terminating in a small foramen which marks a point nearly lialf way to the first molar. Within
this, another shallow groove bounds the more prominent median line. The palatal surface exhibits two shallow lateral grooves, which commence op- posite the posterior border of the first molar.
The grinding surfaces of the molars are transverse ovals, only interrupted by the exterior fissure. The first molar is slightly different in form, being larger, and its section, when not much worn, being nearly round. Its an- terior portion extends towards the alveolus, giving an antero-posterior oval, on prolonged wear. Each tooth has three roots, one interior and two exterior; in the first they may be described as two posterior and one ante- rior. The last molar is the smallest, the series exhibiting a regular grada- tion in size.