Thomomys atrovarius J. A. Allen 1898
Creators: name: Don E. Wilson
name: Thomas E. Lacher, Jr
name: Russell A. Mittermeier
Publisher: name: Lynx Edicions
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Geomyidae
Thomomys
Thomomys atrovarius

description: 10.
Black-and-Brown Pocket Gopher
Thomomys atrovarius
French: Gaufre de Tatemeles / German: Schwarzbraune Taschenratte / Spanish: Tuza negra y marron
Taxonomy. Thomomys atrovarius J. A. Allen, 1898,
“Tatemales [near Rosario], State of Sinaloa, Mexico.”
Placed into subgenus Megascapheus. Considered a subspecies of T. umbrinus by E. W. Nelson and E. A. Goldman in 1934 and J. L. Patton in 2005, but resurrected to species status by M. S. Hafner and colleagues in 2011. Molecular studies show T. atrovarius to be a member of the Thomomys umbrinus species group, which includes T. umbrinus, T. atrovarius, T. sheldoni, and T. nayarensis. Two subspecies recognized.
Subspecies and Distribution.
T.a.atrovariusJ.A.Allen,1898—CSinaloatoSNayaritandadjacentpartsofSWDurangoandNWJalisco,Mexico.
T. a. parviceps Nelson & Goldman, 1934 — NE Sinaloa and W Durango S to C Sinaloa, Mexico.
Descriptive notes. Head-body 110-165 mm, tail 55-80 mm, hindfoot 23-30 mm; weight 75-150 g. Male Black-and-Brown Pocket Gophers are slightly larger than females. This medium-sized pocket gopher has a fusiform body shape typical of all pocket gophers, and it possesses fur-lined cheek pouches that open external to the mouth. Pelage is moderately dense to very sparse, sometimes almost naked on ventrum, and it is dark brown to dull gray-black dorsally, occasionally with a wash of lighter brown or gray laterally. Female Black-and-Brown Pocket Gophers have three pairs of mammae, one pectoral and two inguinal, and baculum in males is usually less than 11 mm in length. Chromosomal complement has 2n = 76 and FN = 116-132.
Habitat. Dry, thornscrub forest. The Black-and-Brown Pocket Gopher occurs in a wide variety of soils from near sea level along the coast of the Pacific Ocean to elevations of ¢.2400 m in the Sierra Madre Occidental. Unlike most species of pocket gophers, the Black-and-Brown Pocket Gopher is only rarely found in agricultural fields, and anecdotal observations suggest that it is reluctant to leave cover of thornscrub forests.
Food and Feeding. There is no specific information available for this species, but all pocket gophers that have been studied to date eat predominately underground roots and tubers and a limited amount of surface vegetation. As in all other pocket gophers, the burrow system is a series of shallow feeding tunnels radiating spoke-like from a deeper, central network that contains one or more nest chambers and several smaller chambers for storage of food or fecal pellets.
Breeding. There is no specific information available for this species, but the Blackand-Brown Pocket Gopher probably breeds during, or soon after, the rainy season (June-August) when vegetation is plentiful.
Activity patterns. The Black-and-Brown Pocket Gopheris active at any hour ofthe day, with periods of peak activity around dawn and dusk. It does not hibernate and is active year-round.
Movements, Home range and Social organization. As in other pocket gophers, Blackand-Brown Pocket Gophers are solitary and aggressively territorial. Because it rarely leaves its burrow system, its home range is defined by size and extent of its burrow system. Field observations suggest that home range sizes of Black-and-Brown Pocket Gophersare typical of other medium-sized pocket gophers, covering 30-80 m? of surface area.
Status and Conservation. The Black-and-Brown Pocket Gopher is not listed on The IUCN Red List because it was traditionally considered a subspecies of the Southern Pocket Gopher (71. umbrinus), which is listed as Least Concern.
Bibliography. Allen (1898a), Hafner et al. (2011), Linzey, Timm, Alvarez-Castafeda & Lacher (2008a), Nelson & Goldman (1934), Patton (2005b).
description: Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Geomyidae, pp. 234-269 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on page 240, DOI: 10.5281/zenodo.6603807