|The Mammals of Texas -
Jones' Pocket Gopher
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.
Distribution 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.