Two New Moles (Genus Scalopus) from Mexico and Texas
ROLLIN H. BAKER
University of Kansas Publications Museum of Natural History
Volume 5, No. 2, pp. 17-24 February 28, 1951
University of Kansas LAWRENCE 1951
UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY
Editors: E. Raymond Hall, Chairman, Edward H. Taylor, A. Byron Leonard, Robert W. Wilson
Volume 5, No. 2, pp. 17-24 February 28, 1951
UNIVERSITY OF KANSAS Lawrence, Kansas
PRINTED BY FERD VOILAND, JR., STATE PRINTER TOPEKA, KANSAS 1951
Two New Moles (Genus Scalopus) from Mexico and Texas
ROLLIN H. BAKER
In the spring of 1950, a field party from the University of Kansas Museum of Natural History including J. R. Alcorn, W. J. Schaldach, Jr., George Newton, and the author collected mammals in the Mexican state of Coahuila. A few days were spent in the Sierra del Carmen. One morning when examining sets for pocket gophers in these mountains, Alcorn found a mole caught in one of the traps. Subsequent examination discloses that this specimen belongs to a heretofore unknown species which may be named and described as follows:
Scalopus montanus new species
Type.—Male, adult, skin and skull plus body skeleton; no. 35668, Univ. Kansas Mus. Nat. Hist.; Club Sierra del Carmen, 2 mi. N and 6 mi. W Piedra Blanca, Coahuila, Mexico; 7 April 1950; obtained by J. R. Alcorn, original no. 11093.
Range.—Known only from the type locality; probably found in other localities in the Sierra del Carmen of northern Coahuila, Mexico.
Diagnosis.—Size medium and slender for the genus (see measurements); tail medium in length, sparsely covered with whitish hairs; claws of forefeet slender; upper parts near (h) Buffy Brown (capitalized color terms after Ridgway, Color Standards and Color Nomenclature, Washington, D. C., 1912), with slight rufous wash on top of head; underparts resemble upper parts but slightly paler with longitudinal band of near (14) Sudan Brown extending from chin posteriorly to and around base of tail, less intense on breast; skull small, arched, and relatively slender especially across mastoidal region; posterior part of cranium depressed; foramen magnum low when viewed from rear; external pterygoid region not greatly expanded; teeth small, especially upper third molar.
Comparison.—From Scalopus aquaticus, of which ten subspecies have been seen including those of significant geographic position, S. montanus differs in: Skull slenderer, less angular and relatively narrower across mastoidal region; cranium arched with hind part flattened; external pterygoid region less expanded; teeth relatively small, especially last upper molar. From S. inflatus, known to me from Jackson's description (N. Amer. Fauna, 38:53-54, pls. 2, 3, September 30, 1915), S. montanus differs in: Skull less angular and slenderer, prelachrymal region not inflated; zygomata slenderer.
Remarks.—S. montanus is known from a single specimen, which represents the second known occurrence of the genus Scalopus in Mexico. The other occurrence is that of S. inflatus in the state of Tamaulipas. S. montanus is geographically isolated in mountainous country from other species of Scalopus. Ten of the recognized subspecies of S. aquaticus were available for examination and descriptions of others were studied. It was found that the number and magnitude of the differences separating any one of these subspecies from an adjoining one was less than those separating S. montanus from S. a. texanus and S. a. intermedius, which are, geographically, closest to S. montanus. S. montanus seems not to be closely related to S. inflatus of Tamaulipas. S. montanus is given specific rank because of the great degree of difference between it and its nearest relatives, and because of its geographically isolated position.
The specimen of S. montanus was taken in a tunnel found by digging away a mound thought to be that of the pocket gopher, Thomomys sturgisi. A trap set in one direction in the tunnel caught the mole; a trap set in the other direction in the tunnel was later covered with soil, evidently by a gopher. After the capture a thorough inspection of the area revealed no "raised" tunnels, typical of Scalopus. A series of Thomomys was taken in this area in sets placed in tunnels found under similar mounds. This locality was near the headquarters of the Club Sierra del Carmen in a parklike stand of oak timber in a canyon, at an elevation of 4950 ft. as recorded by our altimeter. The plant association was judged to be characteristic of the Upper Sonoran Life-zone, not far below the beginning of the Transition Life-zone. The area was heavily grazed by goats, hogs and horses and had little grass or other ground cover under the trees. The soil in this canyon was not deep and consisted of a rocky, marly mixture, pale red in color, evidently produced by weathering of the reddish volcanic rocks bordering the canyon.
The Sierra del Carmen is a high, igneous range, surrounded for the most part by Lower Sonoran plains and desert. Zoologically, these mountains are poorly known. Few collectors have been in the area; most of these have been afforded accommodations through the Club Sierra del Carmen (Carmen Mountain Hunting Club), the members of which have been especially interested in assisting naturalists. Several kinds of mammals are known only from this "biological island" including the pocket gopher mentioned above and the shrew, Sorex milleri. The finding of a mole in the higher elevations of this range suggests that moles may occur in other mountainous areas of Mexico.
Assistance with field work is acknowledged from the Kansas University Endowment Association.
Measurements.—The adult, male holotype measures as follows: Total length, 150; tail vertebrae, 27; hind foot, 20; greatest length (of skull), 32.2; palatilar length, 13.8; mastoidal breadth, 16.2; interorbital breadth, 7.0; maxillary tooth-row, 11.3; greatest depth of skull including auditory bullae, 9.4; weight, 38.6 grams.
Specimen examined.—One, from the type locality.
In studying Scalopus aquaticus texanus, I noted that Allen (Bull. Amer. Mus. Nat. Hist., 3:221, April 29, 1891) based the original description on a single, unsexed specimen taken in Presidio County, Texas, by Wm. Lloyd in September, 1887. Later, Allen wrote (Bull. Amer. Mus. Nat. Hist., 5:200, August 18, 1893) that a series of moles from Rockport, Aransas County, Texas, agreed essentially with the type. True (Proc. U. S. Nat. Mus., 19:22, December 21, 1896) believed that the type was actually from Aransas County rather than Presidio County. This belief was shared by later workers. In checking the literature, I find that the collector of the type, Wm. Lloyd, who was obtaining specimens for George B. Sennett at the time, took other mammals in September as well as in October of 1887 in Presidio County (see Allen, Bull. Amer. Mus. Nat. Hist., 3:221, 223, 224, April 29, 1891) and birds there in June of 1887 (see Sennett, Auk, 5:43, January, 1888). I can find no evidence that Lloyd collected in or near Aransas County in 1887 and see no reason for doubting that the locality, Presidio County, as written on the original label of the type of S. a. texanus is correct. Mr. M. J. Carroll of the Texas State Historical Association advises me that in 1887, Presidio County was reduced to its present size by the creation of Brewster and Jeff Davis counties. Lloyd might have taken the mole in any one of these three Trans-Pecos counties. Even so, these counties are widely separated geographically from the range of other moles designated as S. a. texanus (see Davis, Amer. Midl. Nat., 27:386, March, 1942). The taking of S. montanus in the Sierra del Carmen immediately south of Trans-Pecos Texas leads me to think that Lloyd's mole might have been taken in a mountainous region within one of the three counties mentioned above. A description of Scalopus aquaticus texanus Allen follows:
Scalopus aquaticus texanus Allen
Scalops argentatus texanus Allen, Bull. Amer. Mus. Nat. Hist., 3:221, April 29, 1891.
Type.—Sex unknown, adult, skin no. 3488, skull no. 2740, Amer. Mus. Nat. Hist.; Presidio County, Texas; September, 1887, obtained by Wm. Lloyd.
Range.—Limits of range in Trans-Pecos Texas unknown.
Diagnosis.—Size small; rostrum heavy and broad; lower jaws heavy; palatine space wide with upper tooth-rows arched laterally; teeth large, especially fourth premolar and molars.
Comparison.—From adults of comparable age from Rockport, Aransas County, Texas, S. a. texanus differs in: Rostrum broader and heavier; lower jaws heavier; palatine space wider, with upper tooth-rows more arched laterally; individual teeth in both jaws larger, especially fourth premolar and molars. From S. a. intermedius, which is geographically nearest to the northeast (adult specimens from Meade, Clark and Barber counties, Kansas, and Dewey County, Oklahoma), S. a. texanus differs in: Size smaller; rostrum less massive and shorter; tooth-row shorter.
Remarks.—The type has been previously examined by True (op. cit.:44). The skin is faded and of little taxonomic worth. The anterior part of the skull is present along with both upper tooth-rows and most of the lower jaws. The teeth are well worn, indicative of old adulthood. In size, S. a. texanus appears closest to moles from southern Texas (Rockport) which previously were assigned to the subspecies Scalopus aquaticus texanus. The tooth-rows are of the same length, but the individual teeth of S. a. texanus are significantly larger.
The moles in southern Texas previously ascribed to Scalopus aquaticus texanus seem to be without a name and may be known as follows:
Scalopus aquaticus alleni new subspecies
Scalops texanus, Allen, Bull. Amer. Mus. Nat. Hist., 5:200, August 18, 1893.
Scalops aquaticus texanus True, Proc. U. S. Nat. Mus., 19:21, December 21, 1896.
Scalopus aquaticus texanus Jackson, N. Amer. Fauna, 38:50, September 30, 1915; Miller, U. S. Nat. Mus., Bull. 128:15, April 29, 1924; Davis, Amer. Midl. Nat., 27:386, March, 1942.
Type.—Male, adult, skin no. 7189, skull no. 5788, Amer. Mus. Nat. Hist.; Rockport, Aransas County, Texas; 29 January 1893; obtained by H. P. Attwater.
Range.—Southern Texas, north to Bexar County and east to Refugio County (see Davis, loc. cit.).
Diagnosis.—Size small; according to Davis (loc. cit.), "... length of hind foot seldom more than 19 mm.; total length seldom more than 140 mm. Skull small and flat, seldom exceeding 33 mm. in occipitonasal length and seldom equalling 10 mm. in depth; maxillary breadth usually less than 10 mm.; alveolar length of maxillary tooth row seldom more than 10.5 mm."
Comparison.—From S. a. cryptus, geographically adjacent to the east, S. a. alleni differs in: Size smaller; color paler; skull smaller and flatter. From S. a. intermedius, geographically adjacent to the north, S. a. alleni differs in: Size smaller; skull smaller and flatter with shorter tooth-row (see Davis, op cit.:384, 385). For comparison with S. a. texanus, see account of that subspecies.
Remarks.—This mole is named in honor of Dr. J. A. Allen in recognition for his work on Texas mammals. Grateful acknowledgment is made to those in charge of the collection of Recent mammals in the American Museum of Natural History for permitting me to examine the moles from Aransas County and the type specimen of Scalops argentatus texanus Allen.
Transmitted January 15, 1951.