Distribution.--Desert plains of southwestern Coahuila and northeastern Durango (see [fig. 1]).
Comparisons.--Cratogeomys castanops excelsus is characterized by large size and pale color; it is the palest subspecies of C. castanops. Of adjacent subspecies, excelsus most closely resembles C. c. subsimus which occurs to the east and resembles least C. c. consitus, which occurs to the northwest.
From Cratogeomys castanops subsimus, found to the east, excelsus differs in: Body averaging slightly larger; tail and hind foot shorter; upper parts paler, more light buffy and less yellowish; skull smaller; palate especially shorter; rostrum narrower; nasals shorter; incisors slightly smaller; maxillary tooth-row shorter. Compared with topotypes of C. c. goldmani, found to the south, excelsus differs in: Body larger; hind foot smaller; upper parts in winter pelage paler, more buffy and less rufous; skull larger; zygomata more widely flaring; rostrum broader; nasals shorter; tympanic bullae larger and more inflated; maxillary teeth larger.
Specimens of excelsus from the vicinity of Torreón, in southwestern Coahuila, are slightly smaller in cranial dimensions than more typical examples of the subspecies. In small size, at least, these specimens show some resemblance to goldmani to the south. The range of excelsus approaches that of C. c. consitus in west-central Coahuila (see [fig. 1]), but no evidence of intergradation between these two subspecies could be ascertained. For comparison of excelsus with consitus, see account of the latter.
Remarks.--Cratogeomys castanops excelsus lives in the deep soils of the arid interior basin of southwestern Coahuila and adjacent parts of Durango. This animal is common in the cultivated areas in, and in the vicinity of, the formerly extensive Laguna de Mayrán. East of this laguna the land becomes progressively higher, and C. c. subsimus occurs in the higher, more dissected part of this area.
Specimens examined.--Total, 33, from: 8 mi. E and 2 mi. S Americanos, 3500 ft., 3; 4 mi. N Acatita, 3600 ft., 9; 20 mi. S El Hundido, 1; San Pedro, 2 (BSC); 1 mi. SW San Pedro de las Colonias, 3700 ft., 4; 10 mi. N and 11 mi. W San Lorenzo, 2; 2 mi. E Torreón, 12.
Cratogeomys castanops subsimus Nelson and Goldman
| 1934. | Cratogeomys castanops subsimus Nelson and Goldman, Proc. Biol. Soc. Washington, 47:144, June 13, type from Jaral, Coahuila. |
Distribution.--Desert plains and lower foothills of mountains in south-central Coahuila (see [fig. 1]).
Comparisons.--From Cratogeomys castanops goldmani, found to the southwest, subsimus differs in: Body larger; hind foot larger; upper parts paler, more yellowish and less rufous; skull larger and rougher, having more prominent ridges and crests and deeper fossae for attachment of muscles; zygomata more widely flaring; palate longer; rostrum broader; nasals longer; squamosal breadth greater; maxillary teeth larger. From C. c. subnubilus, found to the south, subsimus differs in: Body larger; tail and hind foot shorter; upper parts paler, more yellowish-buff and less blackish; skull decidedly larger in all respects. From C. c. planifrons, found at higher elevations to the southeast, subsimus differs in the same respects as subsimus differs from subnubilus. For comparisons between subsimus and [subspecies] to the west, north and northeast, see accounts above.