Part 3

Type.--Female, adult, skin and skull; No. 56614, Univ. Kansas Mus. Nat. Hist.; 1.5 mi. NW Ocampo, 3300 ft., Coahuila; 16 December 1953; obtained by Robert W. Dickerman, original number 2164.

Distribution.--Desert plains of north-central Coahuila, surrounded for the most part by higher mountainous country (see fig. 1).

Diagnosis.--Body large for species (see tables 1 and 2); tail short; hind foot large; upper parts Ochraceous-Buff (in summer pelage) and Orange-Buff (in fresh winter pelage); underparts Pale Ochraceous-Salmon; skull medium in size and narrow; zygomata narrow; rostrum narrow; palate short; nasals medium in length; basioccipital small and narrow; mastoid bullae not greatly inflated; tympanic bullae inflated; incisors small; maxillary teeth small.

Comparisons.--From Cratogeomys castanops jucundus, found beyond the mountains to the southeast, sordidulus differs in: Body smaller; tail shorter; hind foot slightly smaller; upper parts darker, more ochraceous and less yellowish, with plumbeous bases of hairs more conspicuous; underparts darker, more buffy and less whitish; skull slightly shorter, more nearly flat, and narrower; zygomata less widely flaring; rostrum narrower; mastoid bullae less inflated; incisors and maxillary teeth slightly smaller. From Cratogeomys castanops excelsus, found to the south and southwest, sordidulus differs in: Body slightly smaller; tail shorter; hind foot slightly larger; upper parts darker, more ochraceous and less pinkish-buff; underparts darker, more buffy and less whitish; skull smaller and narrower; zygomata less widely flaring; sides more nearly parallel and not expanded anteriorly; palate shorter; rostrum narrower and, in relation to greatest length of skull, longer; tympanic bullae slightly more inflated; incisors and maxillary teeth smaller. From Cratogeomys castanops consitus, found to the north and west, sordidulus differs in: Body larger; hind foot larger; upper parts paler, more ochraceous and less rufous; skull decidedly larger and wider; zygomata more widely flaring; palate and nasals longer; rostrum broader; mastoid bullae and tympanic bullae larger; maxillary teeth smaller. From topotypes of Cratogeomys castanops clarkii (Baird), found to the northwest, sordidulus differs in: Body larger; tail shorter; upper parts, in winter pelage, paler, more ochraceous and less dark-rufous; skull slightly smaller and narrower; rostrum narrower; nasals slightly shorter; sides of basioccipital more nearly parallel instead of wedge-shaped; mastoid bullae less inflated; incisor and maxillary teeth smaller. From Cratogeomys castanops convexus, found to the northeast, sordidulus differs in: Body larger; tail shorter; upper parts slightly darker, more ochraceous and less buffy; skull narrower; zygomata more nearly parallel and less expanded anteriorly; rostrum narrower and longer; nasals longer; squamosal breadth greater; mastoid bullae less inflated; maxillary teeth smaller. From Cratogeomys castanops bullatus, found to the east, sordidulus differs in: Body larger; hind foot larger; upper parts darker, more ochraceous and less buffy; skull larger in all respects; zygomata more widely flaring; tympanic bullae less inflated; maxillary teeth larger.

Remarks.--Cratogeomys castanops sordidulus is limited to the Llano de Ocampo, an elevated, desert plain surrounded on three sides, west, south and east, by higher mountainous country which seems to bar the passage of this rodent. On the eastern side this barrier extends north to the very banks of the Río Grande in the Cañon de Boquillas. This subspecies, therefore, is in contact with other populations of Cratogeomys only to the north and northwest. This subspecies is well characterized by size, color and cranial characteristics.

Cratogeomys castanops sordidulus is not abundant; groups of mounds constructed by one or a few individuals were found in widely separated places. Mounds were often small, appeared old and, in other ways, were inconspicuous on arid flats. The animals were taken at elevations as low as 3250 feet and as high as 4150 feet.

Specimens examined.--Total, 13, from: 50 mi. N and 20 mi. W Ocampo, 4150 ft., 1; 18 mi. S and 14 mi. E Tanque Alvarez, 4000 ft., 4; 1-1/2 mi. NW Ocampo, 3300 ft., 6; Ocampo, 1; 5 mi. N and 19 mi. W Cuatro Ciénegas, 3250 ft., 1.

+Cratogeomys castanops consitus+ Nelson and Goldman

1934. Cratogeomys castanops consitus Nelson and Goldman, Proc. Biol. Soc. Washington, 47:140, June 13, type from Gallego, 5500 ft., Chihuahua.

Distribution.--Arid high plains from central Chihuahua, east and southeast at least into northwestern Coahuila (see fig. 1).

Comparisons.--From Cratogeomys castanops lacrimalis Nelson and Goldman, specimens from Boquillas and Marathon north of the Río Grande in Texas, consitus differs in: Body smaller; tail and hind foot shorter; upper parts paler, more light buffy and less rufous; underparts paler, light buffy instead of dark buffy; skull decidedly smaller; zygomata slightly less widely flaring; palate especially shorter; rostrum narrower; squamosal breadth less; incisors smaller. From topotypes of Cratogeomys castanops clarkii, found to the north along the Río Grande, consitus differs in: Body smaller; tail and hind foot shorter; upper parts paler, more buffy and less rufous; skull markedly smaller, especially in palate and nasals; zygomata less widely flaring; tympanic bullae more inflated; mastoid bullae less inflated; basioccipital parallel-sided as opposed to wedge-shaped. From Cratogeomys castanops convexus, found to the east, consitus differs in: Body smaller; tail and hind foot shorter; upper parts paler, more buffy and less ochraceous; underparts paler, white or light buffy instead of pale ochraceous; skull smaller; zygomata less widely flaring; palate shorter; rostrum decidedly narrower and, relative to length of skull, longer; squamosal breadth less; incisors smaller. From Cratogeomys castanops excelsus, found to the south, consitus differs in: Size smaller; tail and hind foot shorter; upper parts darker, more rufous and less pinkish-buff; skull conspicuously smaller, especially in palate, rostrum, and nasals; zygomata less widely flaring; mastoid bullae and tympanic bullae more inflated; incisors smaller; maxillary teeth relatively larger. For comparison of consitus with Cratogeomys castanops sordidulus, see previous account.

Remarks.--Cratogeomys castanops consitus is a small pocket gopher (see tables 1 and 2); the largest adult available to us is much smaller than the smallest adult of any adjacent subspecies. Specimens from Coahuila assigned to consitus compare favorably with topotypes although those from the vicinity of Jaco are smaller, paler and have a narrower rostrum and smaller maxillary teeth. An immature male trapped three miles northeast of Sierra Mojada is tentatively assigned to consitus. This subspecies seems to be rare in northwestern Coahuila and small colonies are widely scattered.

Cratogeomys castanops clarkii (Baird) may occur along the Río Grande in extreme northwestern Coahuila. No specimens are known from Coahuila, and none was found in the vicinity of Boquillas, Coahuila, in 1952.

Specimens examined.--Total, 8, from: 3 mi. N and 9 mi. E El Pino, 1; 6 mi. E Jaco, Chihuahua, in Coahuila, 6; 3 mi. NE Sierra Mojada, 1.

+Cratogeomys castanops excelsus+ Nelson and Goldman

1934. Cratogeomys castanops excelsus Nelson and Goldman, Proc. Biol. Soc. Washington, 47:143, June 13, type from San Pedro, 10 mi. W Laguna de Mayrán, Coahuila.

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.

TABLE 1. ~Measurements of Adult Female Cratogeomys from Coahuila, México~

Table legend: Column A: No. av. or cat. no. Column B: Total length Column C: Length of tail Column D: Length of hind foot Column E: Condylobasal breadth Column F: Zygomatic breadth Column G: Length of palate Column H: Breadth of rostrum Column I: Length of nasals Column J: Squamosal breadth Column K: Alveolar length of maxillary tooth-row