Geomys knoxjonesi
| Jones's Pocket Gopher
(Geomys knoxjonesi) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Rodentia |
| Suborder: | Supramyomorpha |
| Infraorder: | Castorimorphi |
| Superfamily: | Geomyoidea |
| Family: | Geomyidae |
| Subfamily: | Geomyinae |
| Tribe: | Geomyini |
| Genus: | Geomys |
| Subgenus: | Geomys (subgenus) |
| Binomial details | |
| Geomys knoxjonesi R. J. Baker & Genoways, 1975 | |
| Other resources | |
| Full taxonomic details at MDD | |
The Jones's Pocket Gopher (Geomys knoxjonesi) is a small pocket gopher found in western Texas and southeastern New Mexico. It is generally is restricted to deep, sandy soils of aeolian origin within this region (Baker and Genoways, 1975).
Description
From Baker and Genoways (1975): "Size small, both externally and cranially, particularly evident in measurements of cranial length; length of tail proportionally long as compared with the length of head and body. Coloration pale; upper parts buffy-brown, paler on sides and venter; some areas on venter covered with almost pure white hair; feet white."
Museum specimens
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Holotype: TTU-M19872. Geomys knoxjonesi. -
Holotype: TTU-M19872. Geomys knoxjonesi.
External measurements
Length measurements are in millimeters (mm) and weight measurements are in grams (g), unless stated otherwise. If available, the sample size (n=) is provided. If a range is not provided and n= is not given, then the listed measurement represents an average.
| Part of range | Reference | Total length | Tail length | Hindfoot length | Ear length | Mass |
|---|---|---|---|---|---|---|
| Holotype TTU-M19872 (Winkler Co., Texas) | Baker and Genoways (1975) | 238 | 83 | 30 | 6 |
Skull
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Holotype: TTU-M19872. Geomys knoxjonesi. Dorsal view of the skull. -
Holotype: TTU-M19872. Geomys knoxjonesi. Ventral view of the skull. -
Holotype: TTU-M19872. Geomys knoxjonesi. Lateral view of the skull. -
Holotype: TTU-M19872. Geomys knoxjonesi. Dorsal view of the mandible. -
Holotype: TTU-M19872. Geomys knoxjonesi. Dorsal view of the right mandible.
Similar species
From Schmidly & Bradley (2016): "Where the three genera (Cratogeomys, Geomys, and [Megascapheus]) occur in the same general area, as in western Texas, [Megascapheus] usually occupies the shallower rocky soils in the mountains, Geomys lives in the deep sands along the rivers, and Cratogeomys utilizes the areas in between. However, the sandy areas in which no Geomys occur are likely to be occupied by Cratogeomys. The three genera are usually mutually exclusive in their distribution."
Comparison with Cratogeomys castanops
The Yellow-faced Pocket Gopher (Cratogeomys castanops) is a moderately large pocket gopher, dull yellowish brown in color, with one deep groove on outer face of each upper incisor; feet blackish, whereas Geomys knoxjonesi is a small pocket gopher, pale buffy-brown in color, with two longitudinal grooves on outer face of each upper incisor; feet white (Baker and Genoways, 1975; Schmidly and Bradley, 2016).
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Geomys knoxjonesi photographed by Robert Dowler in Gaines County, Texas. -
Yellow-faced Pocket Gopher (Cratogeomys castanops) photographed by Marco Zozaya in Coahuila, Mexico.
Comparison with Geomys bursarius
Populations of Geomys knoxjonesi are in contact with populations of only one other species of Geomys—the Plains Pocket Gopher (Geomys bursarius)—and, therefore, need extensive comparison only with this taxon (Baker and Genoways, 1975). From Baker and Genoways (1975): Individuals of Geomys knoxjonesi are significantly smaller in size than those of Geomys bursarius major (subspecies of Geomys bursarius in western Texas and eastern New Mexico) in several cranial measurements. Geomys knoxjonesi averages smaller than G. b. major in most other characteristics and has a proportionally longer tail. In coloration, knoxjonesi is noticeably paler than major, being a buffy brown rather than a darker (more chocolate) brown on the upper parts.
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Geomys knoxjonesi photographed by Robert Dowler in Gaines County, Texas. -
Plains Pocket Gopher (Geomys bursarius) photographed by Yinan Li in Reno County, Kansas.
References
Baker RJ, Genoways HH. 1975. A new subspecies of Geomys bursarius (Mammalia: Geomyidae) from Texas and New Mexico. Occasional Papers, Museum of Texas Tech University 29:1-18.
Chambers RR, Sudman PD, Bradley RD. 2009. A phylogenetic assessment of pocket gophers (Geomys): evidence from nuclear and mitochondrial genes. Journal of Mammalogy 90(3): 537-547.
Coffman CN, Haynie ML. 2024. Genetic Evidence for the Presence of Geomys jugossicularis in the Oklahoma panhandle. Western North American Naturalist 84(3):320-334.
Schmidly DJ, Bradley RD. 2016. The mammals of Texas. Austin (TX, USA): University of Texas Press.