Thomomys idahoensis

Idaho Pocket Gopher
(*Thomomys idahoensis*)
Idaho Pocket Gopher (Thomomys idahoensis)
Range
Taxonomic classification
Order:	Rodentia
Suborder:	Supramyomorpha
Infraorder:	Castorimorphi
Superfamily:	Geomyoidea
Family:	Geomyidae
Subfamily:	Geomyinae
Tribe:	Thomomyini
Genus:	Thomomys
Binomial details
	Thomomys idahoensis C. H. Merriam, 1901
Other resources
	Full taxonomic details at MDD

Description

From Thaeler, Jr. (1972): "This species, although variable in size, averages small: length of head and body, weight, and length of hindfoot generally less than 150 millimeters, 90 grams, and 26 millimeters, respectively. Dorsal color is variable ranging from yellowish brown with hair tipped with a dark brown to grayish brown or a dark brown. Throughout this color range yellowish rather than reddish tones persist. Dorsal coloration of an individual is fairly uniform with little tendency toward different color on the cheeks, although most specimens show dark gray in the immediate vicinity of the nose. The dorsum lacks any pronounced mid-dorsal darkening, but grades gradually into paler coloration on the venter, which is light gray and often suffused with yellowish or yellowish brown. This species lacks completely, or nearly so, any dark periauricular patches. The feet are whitish and the tail coloration is variable."

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
rangewide	Thaeler, Jr. (1972)	head and body: generally <150		26		90

Skull

From Thaeler, Jr. (1972): " The skull is small and of light construction. Condylonasal length seldom exceeds 35 millimeters and zygomatic breadth seldom exceeds 19.5 millimeters. The incisors (and hence the rostrum) are narrow and not procumbent. The index of procumbency is generally less than -1.0. The auditory and mastoid bullae are large. As a result the posterior end of the s a line connecting the lambdoidal crests. The mastoid bullae are broadly exposed on the posterio-lateral surface of the skull. The interparietal is large and extends posterior of a line connecting the medial terminuses of the parietal-occipital sutures. The length of the posterio-dorsal extension of the premaxillaries relative to that of the nasals is variable but the premaxillaries seldom extend more than 1.0 millimeter beyond the end of the nasals."

Holotype: USNM 23482/30900. Thomomys idahoensis. Adult male. Birch Creek, 10 mi (16 km) south of Nicholia, Lemhi County, Idaho. Collected 8 August 1890. Dorsal view of the skull.
Holotype: USNM 23482/30900. Thomomys idahoensis. Adult male. Birch Creek, 10 mi (16 km) south of Nicholia, Lemhi County, Idaho. Collected 8 August 1890. Ventral view of the skull.
Holotype: USNM 23482/30900. Thomomys idahoensis. Adult male. Birch Creek, 10 mi (16 km) south of Nicholia, Lemhi County, Idaho. Collected 8 August 1890. Lateral view of the skull.
Holotype: USNM 23482/30900. Thomomys idahoensis. Adult male. Birch Creek, 10 mi (16 km) south of Nicholia, Lemhi County, Idaho. Collected 8 August 1890. Dorsal view of the mandible.
Holotype: USNM 23482/30900. Thomomys idahoensis. Adult male. Birch Creek, 10 mi (16 km) south of Nicholia, Lemhi County, Idaho. Collected 8 August 1890. Lateral view of the left mandible.

Similar species

Key to the species of Thomomys by Verts and Carraway (2005)

References

Merriam CH. 1901-07-19. Descriptions of twenty-three new pocket gophers of the genus Thomomys. Proceedings of the Biological Society of Washington 14:107-117.

Thaeler Jr, CS. 1972. Taxonomic status of the pocket gophers, Thomomys idahoensis and Thomomys pygmaeus (Rodentia, Geomyidae). Journal of Mammalogy 53(3): 417-428. https://doi.org/10.2307/1379034