The Project Gutenberg eBook ofGeographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila, México

The Project Gutenberg eBook ofGeographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila, MéxicoThis ebook is for the use of anyone anywhere in the United States and most other parts of the world at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this ebook or online atwww.gutenberg.org. If you are not located in the United States, you will have to check the laws of the country where you are located before using this eBook.Title: Geographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila, MéxicoAuthor: Robert J. RussellRollin H. BakerRelease date: May 31, 2010 [eBook #32623]Language: EnglishCredits: Produced by Chris Curnow, Tom Cos, Joseph Cooper and theOnline Distributed Proofreading Team at http://www.pgdp.net*** START OF THE PROJECT GUTENBERG EBOOK GEOGRAPHIC VARIATION IN THE POCKET GOPHER, CRATOGEOMYS CASTANOPS, IN COAHUILA, MÉXICO ***

This ebook is for the use of anyone anywhere in the United States and most other parts of the world at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this ebook or online atwww.gutenberg.org. If you are not located in the United States, you will have to check the laws of the country where you are located before using this eBook.

Title: Geographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila, MéxicoAuthor: Robert J. RussellRollin H. BakerRelease date: May 31, 2010 [eBook #32623]Language: EnglishCredits: Produced by Chris Curnow, Tom Cos, Joseph Cooper and theOnline Distributed Proofreading Team at http://www.pgdp.net

Title: Geographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila, México

Author: Robert J. RussellRollin H. Baker

Author: Robert J. Russell

Rollin H. Baker

Release date: May 31, 2010 [eBook #32623]

Language: English

Credits: Produced by Chris Curnow, Tom Cos, Joseph Cooper and theOnline Distributed Proofreading Team at http://www.pgdp.net

*** START OF THE PROJECT GUTENBERG EBOOK GEOGRAPHIC VARIATION IN THE POCKET GOPHER, CRATOGEOMYS CASTANOPS, IN COAHUILA, MÉXICO ***

Transcriber's Notes.This file was derived from scanned images. With the exception of two typographical errors that were corrected, removal of an annotation to Figure 1, and rejoining the text which was split by the tables in the printed version, the original text and copies of the included illustrations are presented.Typographical Errors Corrected:Page 603, Paragraph 2:subpecies => subspeciesPage 607, Paragraph 2:Aquanaval => Aguanaval

Transcriber's Notes.

This file was derived from scanned images. With the exception of two typographical errors that were corrected, removal of an annotation to Figure 1, and rejoining the text which was split by the tables in the printed version, the original text and copies of the included illustrations are presented.

Page 603, Paragraph 2:subpecies => subspecies

Page 607, Paragraph 2:Aquanaval => Aguanaval

double barUniversity of Kansas PublicationsMuseum of Natural HistoryVolume 7, No. 12, pp. 591-608double barMarch 15, 1955double barGeographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila, MéxicoBYROBERT J. RUSSELL AND ROLLIN H. BAKERUniversity of KansasLawrence1955University of Kansas Publications, Museum of Natural HistoryEditors: E. Raymond Hall, Chairman, A. Byron Leonard, Robert W. WilsonVolume 7, No. 12, pp. 591-608Published March 15, 1955University of KansasLawrence, KansasPRINTED BYFERD VOILAND, JR., STATE PRINTERTOPEKA, KANSAS1955Look for the Union Label!25-5679

University of Kansas PublicationsMuseum of Natural History

Volume 7, No. 12, pp. 591-608

double barMarch 15, 1955double bar

Geographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila, México

BYROBERT J. RUSSELL AND ROLLIN H. BAKER

University of Kansas Publications, Museum of Natural HistoryEditors: E. Raymond Hall, Chairman, A. Byron Leonard, Robert W. Wilson

Volume 7, No. 12, pp. 591-608Published March 15, 1955

University of KansasLawrence, Kansas

PRINTED BYFERD VOILAND, JR., STATE PRINTERTOPEKA, KANSAS1955Look for the Union Label!25-5679

Geographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila, MéxicoByRobert J. Russell and Rollin H. Baker

Geographic Variation in the Pocket Gopher, Cratogeomys castanops, in Coahuila, México

Robert J. Russell and Rollin H. Baker

The plateau pocket gopher,Cratogeomys castanops, inhabits open lands from southeastern Colorado southward onto the Mexican Plateau as far south as southern San Luis Potosí and southeastern Zacatecas and southeastward to the Coastal Plain of northern Tamaulipas. This species occurs at elevations from as low as 26 feet at Matamoras in Tamaulipas to as high as 8700 feet in valleys of south-eastern Coahuila. In 1934, Nelson and Goldman (Proc. Biol. Soc. Washington, 47:135-154, June 13, 1934) revised the genusCratogeomysand decided that six subspecies ofC. castanopsoccurred in Coahuila. In the present account, we describe four previously unknown subspecies from Coahuila, exclude from the state two others recorded from there by Nelson and Goldman, and show that three others named previously from adjacent Mexican states do occur in Coahuila. This makes eleven subspecies now known from that state. From Coahuila Nelson and Goldman had 35 study specimens ofC. castanopsfrom seven localities and we have had 234 specimens from 63 localities. Consequently we have been able to define with greater certainty, than formerly was possible, the geographic distribution ofC. castanopsin this Mexican state and similarly analyze more completely the geographic variation.

Coahuila is near the center of the geographic range ofC. castanops. The occurrence of 11 subspecies within the state seems to be the result of partial or perhaps, in some cases, total isolation of populations ofC. castanopsbecause of the highly dissected topography and the variability of the soil.Cratogeomys castanopsis a sedentary animal preferring open plains mantled by suitable soils, preferably sandy in texture, in which the animals can dig their elaborate underground systems of runways. Thin soils of hard texture and rocky soils do not offer optimum habitat forC. castanops, and the animals usually are absent or uncommon in such situations. Desert mountains with their thin rocky soils, elevated passes, perpendicular rocky cliffs, and stands of oaks and conifers at higher elevations present impassable barriers for pocket gophers of this species. The Río Grande, bordering Coahuila to the north, in many places flowingthrough steep-walled cañons, also seems to be a barrier that this fossorial rodent does not cross; distinct subspecies occur on the two sides of the river directly opposite each other (also see Nelson and Goldman,op. cit.: 143). Smaller streams, such as the Río Salado, Río Nazas and Río Salinas, seem to be unimportant barriers to the passage of these pocket gophers. The food supply ofC. castanopsseems adequate in most situations and consequently food is unimportant in governing the distribution of this species. Principal foods ofC. castanopsare fleshy tuberous roots of well-distributed desert shrubs, but in the valleys of the high mountains of southeastern Coahuila, where desert shrubs are absent, roots and leaves of low-growing forbs are eaten.

Three distinct habitats forC. castanopsoccur in Coahuila. The state is crossed by a series of mostly impassable, mountainous ridges beginning at the northwestern boundary at the Cañon de Boquillas on the Río Grande and extending southeastward to the east-central border. This divides Coahuila into a more humid and less elevated northeastern area which is an inland extension westward of the Coastal Plain and a more arid and higher western and southern area which is a part of the "Mesa del Norte" of the Mexican Plateau. In the extreme southeast the still higher elevated plains and intermontane valleys within the Sierra Madre Oriental afford a third habitat for populations of this species. The subspecies of these pocket gophers found in any one of these three habitats show greater affinity to each other than they do to any subspecies found in the other habitats.

Generally speaking, populations ofC. castanopsfrom northeastern Coahuila are related, as a group, in color and cranial features. Partial isolation of subspecies in this area results chiefly from discontinuity of suitable soils rather than from topography. These pocket gophers occur most commonly in the deep, sandy soils which are found along streams, especially where farm lands are irrigated. In western and southern Coahuila, mountains extending in both north-south and east-west directions act as partial barriers to the passage ofC. castanops. Within this large area, pocket gophers occur in desert basins many of which are enclosed on two or more sides by mountains. Even so, with the exception of the smallerC. c. consitusof northwestern Coahuila, all known subspecies occurring at lower elevations in the western and southern part of the state show close relationships in color and cranial features. Those subspecies in the higher parts of southeastern Coahuila by their smallsize and dark color reflect to a high degree their isolation in an elevated habitat.

Males ofC. castanopsdiffer greatly from females of equal age; consequently animals of the same sex, as well as of the same age, are used herein for taxonomic comparisons. Since, of any given age-group, females show less individual variation than do males, we have relied more on the characteristics of the females in this taxonomic study. Only specimens taken at approximately the same times of the year have been compared for color of pelage. Capitalized color terms are those of Ridgway, Color Standards and Color Nomenclature, Washington, D. C., 1912. Specimens made available through the courtesy of the authorities of the Biological Surveys Collection of the United States National Museum are indicated in the accounts of subspecies as BSC; other specimens listed are in the collection of the University of Kansas Museum of Natural History. Assistance with field work is acknowledged from the Kansas University Endowment Association and the National Science Foundation.

In any one of the lists of "Specimens examined" beyond, the order of arrangement of the localities is from north to south. Those localities listed in Roman type are represented on the distribution map (Figure 1) by blacked-in circles. Each of several circles covers two or more localities because the localities are close together. In any such instance the northernmost place is listed in Roman type and the names of the other places follow in Italic type. Measurements in millimeters are given intable 1for females and intable 2for males.

Cratogeomys castanops convexusNelson and Goldman

Distribution.--Extreme northern Coahuila, east and north of the Serranías del Burro (seefig. 1).

Diagnosis.--Previously known from only one specimen, a subadult female, this subspecies has not been well diagnosed. At hand we have five near topotypes ofconvexus(including two adult females and one adult male) and specimens assignable to this subspecies from several other localities. This subspecies may be characterized as follows: Size medium (seetables 1 and 2); dorsal profile of skull convex in females and flat, especially posteriorly, in males; zygomata weakly constructed and not widely flaring; mastoid and tympanic bullae inflated; nasals short; rostrum broad and short; maxillary teeth large.

Geographic ranges of the subspecies of Cratogeomys castanopsFig. 1.Geographic ranges of the subspecies ofCratogeomys castanopsfound in Coahuila, México.Click on ap to view larger sized.

Fig. 1.Geographic ranges of the subspecies ofCratogeomys castanopsfound in Coahuila, México.

Comparisons.--From topotypes ofCratogeomys castanops angusticepsNelson and Goldman, found to the north and east across the Río Grande in Texas,convexusdiffers in: Body larger; upper parts more reddish, especially on sides; skull with zygomata less heavy, nasals broader, pterygoids smaller, maxillary teeth larger. For comparisons ofconvexuswith the subspecies ofC. castanopsfound to the west, south and southeast, see accounts of the subspecies to follow.

Remarks.--The geographic range ofconvexusis restricted, being bounded on the west and southwest by mountains, especially the Serranías del Burro, and on the north and east by the Río Grande. The range of the subspecies found to the southeast may not be continuous with that ofconvexus. At least, in the area between Villa Acuña and Piedras Negras, along the Río Grande, no specimens were obtained and no sign was observed. We suspect that in this area the species occurs only locally if at all.A specimen taken near the Río Grande in Coahuila, opposite Samuels, Texas, and assigned toCratogeomys castanops clarkiiby Nelson and Goldman (op. cit.:140), has been examined by us and is referable toconvexus. This specimen is typical ofconvexusexcept for the lesser inflation of the mastoid bullae and tympanic bullae. Conspicuous differences betweenconvexusandangusticepsindicate that the Río Grande is an effective barrier to passage by these rodents.

A specimen taken near the Río Grande in Coahuila, opposite Samuels, Texas, and assigned toCratogeomys castanops clarkiiby Nelson and Goldman (op. cit.:140), has been examined by us and is referable toconvexus. This specimen is typical ofconvexusexcept for the lesser inflation of the mastoid bullae and tympanic bullae. Conspicuous differences betweenconvexusandangusticepsindicate that the Río Grande is an effective barrier to passage by these rodents.

Specimens examined.--Total, 14, all from Coahuila: Río Grande, 17 mi. S Dryden, Terrell Co., Texas, 6; Río Grande, opposite Samuels, Val Verde Co., Texas, 1 (BSC); Villa Acuña, 5; Cañon del Cochino, 21 mi. E and 16 mi. N Piedra Blanca, 1; 11 mi. W Hda. San Miguel, 1.

Cratogeomys castanops bullatusnew subspecies

Type.--Female, adult, skin and skull, No. 48498, Univ. Kansas Mus. Nat. Hist., 2 mi. S and 6-1/2 mi. E Nava, 810 ft., Coahuila; 16 June 1952; obtained by Robert J. Russell, original number 276.

Distribution.--Desert lowlands of northeastern Coahuila, from the Río Grande to as far southwestward as the Río Sabinas (seefig. 1).

Diagnosis.--Body medium for the species (seetables 1 and 2); tail long; hind foot small; upper parts Light Ochraceous-Buff (in summer pelage) and Orange-Buff (in winter pelage), bases of hairs Plumbeous; underparts white to pale buffy; skull small, broad and slightly convex in dorsal outline; zygomata widely flaring; palate short; rostrum short; nasals short; mastoid and tympanic bullae inflated; basioccipital with lateral edges parallel; maxillary teeth small.

Comparisons.--FromCratogeomys castanops convexus, found to the north,bullatusdiffers in: Hind foot shorter; skull much broader in relation to length; rostrum narrower but, relative to length of skull, wider; tympanic bullae slightly more inflated; incisors and maxillary teeth smaller. From topotypes ofCratogeomys castanops angusticeps, found across the Río Grande and upstream from localities wherebullatusis known to occur,bullatusdiffers in: Body slightly smaller; color paler, especially on sides; skull shorter and broader; rostrum shorter and broader; nasals shorter; mastoid and tympanic bullae more inflated; maxillary teeth smaller. For comparisons ofbullatuswith the subspecies ofC. castanopsfound to the west and south, see accounts of the subspecies to follow.

Remarks.--Cratogeomys castanops bullatusin small size resemblesC. c. tamaulipensisNelson and Goldman of the lower Río Grande Valley in Tamaulipas, but the two differ markedly in cranial features.Cratogeomys c. bullatusis smaller thanconvexusbut these two subspecies resemble each other in color and cranial characters. Both have an arched skull, inflated mastoid and tympanic bullae, short nasals, and a short rostrum. Comparison ofbullatuswithangusticeps, which occurs across the Río Grande but not directly opposite the range ofbullatus, indicates that these two subspecies are less closely related thanbullatusis totamaulipensisandconvexus.Cratogeomys castanops bullatusis especially common in sandy soils in the vicinity of Nava where the mounds were in fallow irrigated fields and other open places between extensive live oak thickets. South and west of the Río Grande the animals were less abundant and lived in heavier soils usually as individuals or in small groups. Specimens were taken at elevations from as low as 800 feet to as high as 2,000 feet.

Cratogeomys castanops bullatusis especially common in sandy soils in the vicinity of Nava where the mounds were in fallow irrigated fields and other open places between extensive live oak thickets. South and west of the Río Grande the animals were less abundant and lived in heavier soils usually as individuals or in small groups. Specimens were taken at elevations from as low as 800 feet to as high as 2,000 feet.

Specimens examined.--Total, 24, from: 2 mi. S and 6-1/2 mi. E Nava, 810 ft., 2; 2 mi. S and 12 mi. E Nava, 800 ft., 1;3 mi. S and 12 mi. E Nava, 800 ft., 4; 29 mi. N and 6 mi. E Sabinas, 5; 10 mi. E Hacienda La Mariposa, 2000 ft., 1; La Gacha [= La Concha], 1600 ft., 8; 8 mi. S and 8 mi. E Hacienda La Mariposa, 1900 ft., 1; 9 mi. S and 11 mi. E Sabinas, 1050 ft., 2.

Cratogeomys castanops ustulatusnew subspecies

Type.--Female, adult, skin and skull, No. 34589, Univ. Kansas Mus. Nat. Hist., Don Martin, 800 ft., Coahuila; 19 August 1949; obtained by W. Kim Clark, original number 1034.

Distribution.--Extreme northeastern Coahuila from the vicinity of Presa Don Martin southward into northwestern Neuvo León in the valley of the Río Salado and its tributaries at least as far south as the vicinity of Vallecillo (seefig. 1).

Diagnosis.--Body large for species (seetables 1 and 2); hind foot short; upper parts Apricot Buff (in fresh summer pelage) and Salmon-Buff strongly mixed with black (in fresh winter pelage); underparts Light Ochraceous-Buff; skull large, especially in females, and broad; zygomatic arches widely flaring; palate long; rostrum broad; nasals long; mastoid and tympanic bullae not conspicuously inflated; incisors narrow; maxillary teeth large.

Comparisons.--FromCratogeomys castanops bullatusfound to the north,ustulatusdiffers in: Body larger; tail shorter; upper parts darker, more rufous and less buffy; skull larger, especially in palate, nasals, and rostrum; zygomata more widely flaring; tympanic bullae less inflated; incisors slightly larger; maxillary teeth larger. From topotypes ofCratogeomys castanops tamaulipensisfound to the southeast,ustulatusdiffers in: Body larger; upper parts, in winterpelage, darker, more rufous and less buffy; underparts paler; skull larger, especially in palate, rostrum and nasals; zygomata more widely flaring; tympanic bullae more inflated; pterygoids larger; basioccipital narrower, its sides parallel instead of convex; maxillary teeth smaller. FromCratogeomys castanops subsimus, found to the southwest,ustulatusdiffers in: Tail shorter; hind foot smaller; upper parts darker, more rufous and less pinkish-buff; skull shorter; zygomata less widely flaring; palate shorter; rostrum averaging slightly narrower; nasals shorter; incisors narrower; maxillary teeth slightly smaller. For comparison ofustulatuswith the subspecies ofC. castanopsto the southwest, see account of that subspecies to follow.

Remarks.--Cratogeomys castanops ustulatusis a large-sized pocket gopher with a relatively larger, skull. In size of skull,ustulatusis exceeded only byC. c. subsimusfound beyond the mountains in the southern part of Coahuila. In size,ustulatusdiffers so markedly frombullatusthat the two can be distinguished easily by this feature alone. The skull ofC. c. convexusapproaches that ofustulatusin size, but is smaller in all respects, save breadth of rostrum.This pocket gopher is found commonly along the Río Salado and its watershed. Fallow cotton fields in the vicinity of Anahuac [= Rodríques], Nuevo León, are preferred living places. This subspecies was found at elevations as high as 1000 feet and as low as 600 feet.

This pocket gopher is found commonly along the Río Salado and its watershed. Fallow cotton fields in the vicinity of Anahuac [= Rodríques], Nuevo León, are preferred living places. This subspecies was found at elevations as high as 1000 feet and as low as 600 feet.

Specimens examined.--Total, 10, from: Don Martin, 800 ft., 5;base of Don Martin Dam, 2;2 mi. SE Don Martin Dam, along Río Salado, 2; 5 mi. SE Don Martin, 1.

Records from Nuevo León.--Total, 14, from: 9 mi. N and 2 mi. W Anahuac [= Rodríques], 1; 4 mi. N and 1 mi. W Anahuac [= Rodríques], 5; 3 mi. N Lampazos, 4; 1 mi. N Vallecillo, 1000 ft., 1; Vallecillo, 20 mi. S Río Salado, 1000 ft., 3.

Cratogeomys castanops jucundusnew subspecies

Type.--Female, adult, skin and skull; No. 56603, Univ. Kansas Mus. Nat. Hist.; Hermanas, 1205 ft., Coahuila; 5 December 1953; obtained by Robert W. Dickerman, original number 2051.

Distribution.--Arid plains and broad intermontane valleys of east-central Coahuila (seefig. 1).

Diagnosis.--Body largest for the species (seetable 1); tail long; hind foot large; upper parts in winter pelage Ochraceous-Buff, in summer pelage Antimony Yellow; underparts Pale Ochraceous-Buff; skull medium in size, broad; zygomata moderately flaring; palate medium in length; rostrum broad; nasals moderately long; maxillary teeth small.

Comparisons.--FromCratogeomy castanops ustulatus, found to the east, jucundus differs in: Body larger; tail longer; hind foot larger; upper parts paler, more ochraceous and less rufous; skull averaging smaller; zygomata slightly less expanded laterally; palate and nasals shorter; squamosal breadth less; mastoid bullae less inflated, especially in females; rostrum slightly narrower; maxillary tooth-row shorter. From topotypes ofCratogeomys castanops tamaulipensis, found to the southeast,jucundusdiffers in: Body larger; tail longer; hind footsmaller; upper parts, in winter pelage, paler, more ochraceous and less rufous; skull larger; zygomata more widely flaring; palate longer; rostrum broader; tympanic bullae more inflated; basioccipital with sides parallel instead of convex; maxillary teeth smaller. FromCratogeomy castanops excelsus, found to the southwest,jucundusdiffers in: Body larger; hind foot averaging larger; upper parts darker, more ochraceous, and less buffy; underparts darker, more buffy and less whitish; skull slightly smaller; zygomata less widely flaring, especially in females; palate shorter; nasals shorter; squamosal breadth less; mastoid bullae more inflated; incisors narrower. FromCratogeomys castanops subsimus, found to the south,jucundusdiffers in: Body larger; tail shorter; hind foot shorter; upper parts paler, more ochraceous and less yellowish; skull smaller; zygomata less widely expanded laterally; palate and nasals shorter; rostrum narrower; squamosal breadth less; maxillary tooth-row shorter. FromCratogeomys castanops bullatus, found to the north,jucundusdiffers in: Body larger; tail averaging longer; hind foot larger; color of upper parts more ochraceous and less rufous; underparts darker, more buffy and less whitish; skull larger, especially in length, in width across zygomata, in lengths of palate, rostrum and nasals; mastoid and tympanic bullae less inflated; squamosal breadth greater.

Remarks.--Cratogeomys castanops jucundusis large, exceeding subsimus in dimensions of the body, but differing fromsubsimusin relatively smaller skull. Passage to the north and northeast byjucundusis at least partly blocked by inhospitable mountainous country; the resulting semi-isolation may be one reason for the distinctive characteristics ofjucunduscompared with those ofbullatusandustulatus. Two specimens from Monclova, assigned totamaulipensisby Nelson and Goldman (op. cit.:142), are here referred tojucunduson the basis of cranial characters and size.Specimens were trapped in fallow irrigated fields in the vicinity of Monclova. Others were taken in deep soils in desert flats.

Specimens were trapped in fallow irrigated fields in the vicinity of Monclova. Others were taken in deep soils in desert flats.

Specimens examined.--Total, 19, from: Hermanas, 1205 ft., 9;1 mi. S Hermanas, 2; 1 mi. N and 13 mi. E Cuatro Ciénegas, 2; 5 mi. N and 2 mi. W Monclova, 1;2 mi. N and 1 mi. E Monclova, 1; Monclova, 2 (BSC); Hisachalo [= Huisachalo], 2.

Cratogeomys castanops sordidulusnew subspecies

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 (seefig. 1).

Diagnosis.--Body large for species (seetables 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.--FromCratogeomys castanops jucundus, found beyond the mountains to the southeast,sordidulusdiffers 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. FromCratogeomys castanops excelsus, found to the south and southwest,sordidulusdiffers 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. FromCratogeomys castanops consitus, found to the north and west,sordidulusdiffers 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 ofCratogeomys castanops clarkii(Baird), found to the northwest,sordidulusdiffers 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. FromCratogeomys castanops convexus, found to the northeast,sordidulusdiffers 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. FromCratogeomys castanops bullatus, found to the east,sordidulusdiffers 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 sordidulusis 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 ofCratogeomysonly to the north and northwest. This subspecies is well characterized by size, color and cranial characteristics.Cratogeomys castanops sordidulusis 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.

Cratogeomys castanops sordidulusis 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 consitusNelson and Goldman

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

Comparisons.--FromCratogeomys castanops lacrimalisNelson and Goldman, specimens from Boquillas and Marathon north of the Río Grande in Texas,consitusdiffers 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 ofCratogeomys castanops clarkii, found to the north along the Río Grande,consitusdiffers 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. FromCratogeomys castanops convexus, found to the east,consitusdiffers 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. FromCratogeomys castanops excelsus, found to the south,consitusdiffers 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 ofconsituswithCratogeomys castanops sordidulus, see previous account.

Remarks.--Cratogeomys castanops consitusis a small pocket gopher (seetables 1 and 2); the largest adult available to us is much smaller than the smallest adult of any adjacent subspecies. Specimens from Coahuila assigned toconsituscompare 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 toconsitus. 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.

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,inCoahuila, 6; 3 mi. NE Sierra Mojada, 1.

Cratogeomys castanops excelsusNelson and Goldman

Distribution.--Desert plains of southwestern Coahuila and northeastern Durango (seefig. 1).

Comparisons.--Cratogeomys castanops excelsusis characterized by large size and pale color; it is the palest subspecies ofC. castanops. Of adjacent subspecies, excelsus most closely resemblesC. c. subsimuswhich occurs to the east and resembles leastC. c. consitus, which occurs to the northwest.

FromCratogeomys castanops subsimus, found to the east,excelsusdiffers 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 ofC. c. goldmani, found to the south,excelsusdiffers 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 ofexcelsusfrom 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 togoldmanito the south. The range ofexcelsusapproaches that ofC. c. consitusin west-central Coahuila (seefig. 1), but no evidence of intergradation between these two subspecies could be ascertained. For comparison ofexcelsuswithconsitus, see account of the latter.

Remarks.--Cratogeomys castanops excelsuslives 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, andC. c. subsimusoccurs 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 subsimusNelson and Goldman

Distribution.--Desert plains and lower foothills of mountains in south-central Coahuila (seefig. 1).

Comparisons.--FromCratogeomys castanops goldmani, found to the southwest,subsimusdiffers 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. FromC. c. subnubilus, found to the south,subsimusdiffers in: Body larger; tail and hind foot shorter; upper parts paler, more yellowish-buff and less blackish; skull decidedly larger in all respects. FromC. c. planifrons, found at higher elevations to the southeast,subsimusdiffers in the same respects assubsimusdiffers fromsubnubilus. For comparisons betweensubsimusandsubspeciesto the west, north and northeast, see accounts above.

TABLE 1.Measurements of Adult Female Cratogeomys fromCoahuila, MéxicoTable legend:Column A:No. av. or cat. no.Column B:Total lengthColumn C:Length of tailColumn D:Length of hind footColumn E:Condylobasal breadthColumn F:Zygomatic breadthColumn G:Length of palateColumn H:Breadth of rostrumColumn I:Length of nasalsColumn J:Squamosal breadthColumn K:Alveolar length of maxillary tooth-row=ABCDEFGHIJKC. c. convexus, Villa Acuña52259260863750.631.733.811.716.729.19.352261265833849.331.632.911.815.828.910.6C. c. bullatus, vicinity of Nava5 Av.256803647.430.632.610.717.127.99.5Min.242723547.030.632.310.016.527.59.2Max.263853747.731.132.911.617.828.29.8C. c. ustulatus, vicinity of Don Martin8 Av.273743651.433.535.411.818.830.110.0Min.261643550.732.634.811.017.829.19.3Max.280833852.134.136.512.519.230.810.6C. c. jucundus, Hermanas4 Av.296853950.933.034.611.518.029.69.4Min.294833849.832.133.811.017.029.09.1Max.298863951.833.835.011.618.630.19.6C. c. sordidulus, 1.5 mi. NW Ocampo3 Av.276793750.431.734.610.918.230.09.1Min.270753649.530.633.810.317.729.88.9Max.288853951.432.435.211.418.530.19.2C. c. consitus, 6 mi. E Jaco, Chihuahua, in Coahuila4 Av.229743243.828.129.69.716.026.28.9Min.226683142.627.329.49.415.525.78.1Max.232783245.828.829.99.916.226.99.2C. c. excelsus, 4 mi. N Acatita4 Av.284823751.434.135.411.618.931.29.5Min.274773551.133.634.710.418.430.59.2Max.291863851.634.936.112.120.131.79.9C. c. subsimus, 12 mi. N and 10 mi. E Parras34937287873953.134.936.911.519.431.710.5Jaral (BSC)510492951044053.234.136.912.618.729.710.0C. c. goldmani, 1 mi. S Jimulco55611250853546.032.631.410.716.327.89.8C. c. subnubilus, 1 mi. S Carneros33128220652940.827.927.28.712.724.78.12 mi. W San Miguel33132222653040.426.326.68.113.224.58.41 mi. N Agua Nueva33127220742941.824.628.48.314.223.98.48 mi. N La Ventura34934235763042.227.928.59.014.326.37.8C. c. planifrons, 12 mi. W San Antonio de las Alazanas5 Av.244663243.728.029.19.414.526.28.6Min.239623143.327.528.78.913.625.38.3Max.247693344.328.59.49.715.326.88.9

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