Spermophilus spilosoma oricolus Alvarez
Spotted Ground Squirrel
1962. Spermophilus spilosoma oricolus Alvarez, Univ. Kansas Publ., Mus. Nat. Hist., 14:123, March 7, type from 1 mi. E La Pesca, Tamaulipas.
Distribution in Tamaulipas.—Known only from the type locality and from parts of the barrier beach, but possibly occurs at other places in northeastern parts of state.
The 10 specimens from the type locality were trapped or shot on the beach, which was covered by thick, low, scattered bushes and grass. Of the many holes found there, some probably were used by ground squirrels and others by crabs. A female, taken on July 7 with two young at a place 33 miles south of Washington Beach, weighed 133 grams and had six placental scars. This specimen (reported as Spermophilus spilosoma annectens by Selander et al., 1962:335) resembles others examined from the barrier beach (see Alvarez, 1962:124) and is therefore assigned to S. s. oricolus.
Records of occurrence.—Specimens examined, 24: 33 mi. S Washington Beach, 1; 88 mi. S, 10 mi. W Matamoros, 12; 89 mi. S, 10 mi. W Matamoros, 1; 1 mi. E La Pesca, 10.
Spermophilus variegatus couchii Baird
Rock Squirrel
1855. Spermophilus couchii Baird, Proc. Acad. Nat. Sci. Philadelphia, 1:332, April, type from Santa Catarina, a few miles west of Monterrey, Nuevo León.
1955. Spermophilus variegatus couchii, Baker, Univ. Kansas Publ., Mus. Nat. Hist, 9:207, June 15.
Distribution in Tamaulipas.—Possibly in southwestern part; reported only from Ciudad Victoria (Howell, 1938:141).