Thomomys umbrinus
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 umbrinus

description: 8.
Southern Pocket Gopher
Thomomys umbrinus
French: Gaufre méridional / German: Sidliche Taschenratte / Spanish: Tuza meridional
Other common names: Animas Mountains Pocket Gopher
Taxonomy. Geomys umbrinus Richardson, 1829,
“Cadadaguois, a town in southwestern part of Louisiana.” Corrected by V. Bailey in 1906 to the “Boca del Monte, Vera Cruz, Mexico.”
Placed into subgenus Megascapheus. Molecular studies show 7. umbrinus to be a member of the 7. umbrinus species group, which also includes 71. atrovarius, T. sheldoni, and T. nayarensis. Thirty-two subspecies were listed by J. L. Patton in 1999 and 23 were recognized by Patton in 2005, but subsequent elevation of T. atrovarius and T. sheldoni to species rank, followed by a systematic revision of 7. umbrinus by V. L. Mathis and colleagues in 2014 reduced the number of subspecies considerably. Four subspecies recognized.
Subspecies and Distribution.
T.u.umbrinusRichardson,1829—ECZacatecas,SthroughtheTrans-MexicoVolcanicBelt,intoWCVeracruz(PicodeOrizaba),Mexico.
T.u.durangiNelson&Goldman,1934—SWDurangoandNWZacatecas,Mexico.
T.u.goldmaniMerriam,1901—CChihuahuaandSWCoahuilaintoECDurango,Mexico.
T. u. intermedius Mearns, 1897 — SE Arizona and SW New Mexico, USA, S into Sonora and NW Chihuahua, Mexico.
Descriptive notes. Head-body 130-180 mm (males) and 120-170 mm (females), tail 65-80 mm (males) and 55-70 mm (females); weight 110-180 g (males) and 80-120 g (females). Male Southern Pocket Gophers are usually larger than females; thisis especially pronounced in populations with larger average body size. 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. Bodysize and pelage color vary considerably among populations, with those living in hot, dry habitats at low elevations being much smaller and paler than populations living in moist and cool montane meadows at high elevations. Most individuals are light to dark brown dorsally, occasionally with a faint, slightly darker dorsal stripe. Females have three pairs of mammae, one pectoral and two inguinal. The Southern Pocket Gopheris the only member of this species group with a 2n = 78 karyotype; FN = 96-152.
Habitat. Low-elevation desert grasslands and scrublands through mid-elevation oak and pine-oak woodlands to high-elevation coniferous forests.
Food and Feeding. There is no specific information available for this species, but all pocket gophers that have been studied 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 chambersfor storage of food orfecal pellets. Surface feeding activity in the immediate vicinity of the borrow entrance has been reported for the Southern Pocket Gopher.
Breeding. Breeding season of the Southern Pocket Gopher varies greatly acrossits distribution, with low-elevation individuals breeding in early spring and high-elevation individuals in late spring. Most populations are thought to breed only once per year, but some populations in Mexico may breed twice per year. Breeding habits of the Southern Pocket Gopher are probably like those of all other members of the genus, with litter sizes of 1-10 young and averaging 4-5 young/litter.
Activity patterns. There is no specific information available for this species, but field studies show the Southern Pocket Gopher to be active at any hour of the 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. The Southern Pocket Gopheris solitary and aggressively territorial. Because it rarely leavesits burrow system, its home range is defined by size and extent ofits burrow system. Field observations suggest that home range sizes are typical of those measured in other medium-sized pocket gophers, covering 30-80 m? of surface area.
Status and Conservation. Classified as Least Concern on The IUCN Red List.
Bibliography. Bailey (1906), Castro-Campillo & Ramirez-Pulido (2000), Hafner et al. (1987), Linzey, Timm, Alvarez-Castaneda & Lacher (2008a), Mathis et al. (2014), Nelson & Goldman (1934), Patton (1999g, 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 239, DOI: 10.5281/zenodo.6603807