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  The Mammals of Texas - Online Edition

Jones' Pocket Gopher
Order Rodentia : Family Geomyidae : Geomys knoxjonesi Baker and Genoways

Description. This is a cryptic species of the plains pocket gopher, G. bursarius. Morphologically, Jones’ pocket gopher appears to be slightly smaller, both externally and cranially, than the plains pocket gopher but careful study of genetic characters is required before the two may be distinguished. Coloration is buff-brown dorsally, somewhat paler on the sides and ventrally, with white feet. Dental formula as in G. bursarius.

Species distribution mapDistribution in Texas. Southwestern plains of Texas and southeastern plains of New Mexico. In Texas, known from Cochran, Yoakum, Terry, Gaines, Andrews, Martin, Winkler, Ward, and Crane counties at sites of deep sandy soils of aeolian origin.

Habits. The habits of G. knoxjonesi are similar to G. bursarius. Although genetic evidence for hybridization with G. bursarius has been found, the apparent zone of contact between the two species is extremely narrow and the resultant hybrid offspring are sterile or have a lower level of fertility, indicating that the two species rarely interact reproductively.

Remarks. Originally recognized as a new subspecies of G. bursarius in 1975, additional genetic analysis of this pocket gopher by Robert Baker and his students has subsequently shown that Jones’ pocket gopher is essentially reproductively isolated from G. bursarius and therefore constitutes a separate species.