Goldman (Jour. Washington Acad. Sci., 28:342, July 15, 1938) named the subspecies _Thomomys bottae pinalensis_ on the basis of only one specimen, an immature female (245709 BS) from Oak Flat, five miles east of Superior, Pinal Mountains, Arizona. Examination shows it to be indistinguishable in characters of taxonomic importance (coloration, external measurements, shape of skull and size of skull) from specimens of _T. b. mutabilis_ of comparable sex and age. No. 245709 is well within the limits of individual variation of _T. b. mutabilis_ as is shown by the several specimens (all in the U. S. Biological Surveys Collection) as follow: Nos. 214118, 214670 (topotypes from Camp Verde, Arizona), 212707 (Chiricahua Ranch, 20 mi. E Calva), 208635 (H-bar Ranch, 20 mi. S Payson), and 215762 (Turkey Creek). Therefore, the name _Thomomys bottae pinalensis_ is here arranged as a synonym of the earlier name, _Thomomys bottae mutabilis_ Goldman (Proc. Biol. Soc. Washington, 46:75, April 27, 1933), the type locality of which is Camp Verde, Yavapai County, Arizona.
When Goldman (Jour. Washington Acad. Sci., 26:113, March 15, 1936) named the subspecies _Thomomys bottae desitus_, he assigned to it (_op. cit._:114) 10 specimens obtained at Wickenburg, Maricopa County, Arizona. He did not mention specimens from Wickenburg when he subsequently named the subspecies _Thomomys bottae patulus_ (Jour. Washington Acad. Sci., 28:341, July 15, 1938) and stated that _T. b. patulus_ was known only from the type locality in the "bottomland along [the] Hassayampa River, two miles below Wickenburg." Examination in 1950 of specimens referable to _T. b. patulus_ in the U. S. Biological Surveys Collection shows all of them, including the holotype, to be labeled "Wickenburg." The 10 specimens from Wickenburg reported by Goldman in 1936 as _T. b. desitus_ were included by him among the 16 (actually 17, one being a skull only) upon which he based his description of _T. b. patulus_ in 1938. Examination of the field catalogues of 3 of the 4 collectors who obtained the specimens discloses that only the 7 specimens obtained last were recorded as occurring in the Hassayampa River bottoms; the first 10 were recorded only as from "Wickenburg." Briefly, only one subspecies, _T. b. patulus_, is present in the area, and Goldman in 1938 seems to have thought that the two localities were actually the same, and that "2 miles below Wickenburg" was the more precise designation.