HotFreeBooks.com
Taxonomy and Distribution of Some American Shrews
by James S Findley
Home - Random Browse

UNIVERSITY OF KANSAS PUBLICATIONS MUSEUM OF NATURAL HISTORY

Volume 7, No. 14, pp. 613-618

June 10, 1955



Taxonomy and Distribution of Some American Shrews

BY

JAMES S. FINDLEY



UNIVERSITY OF KANSAS LAWRENCE 1955



UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, A. Byron Leonard, Robert W. Wilson

Volume 7, No. 14, pp. 613-618 Published June 10, 1955



UNIVERSITY OF KANSAS Lawrence, Kansas



PRINTED BY FERD VOILAND, JR., STATE PRINTER TOPEKA, KANSAS 1955

25-7329



Taxonomy and Distribution of Some American Shrews

by James S. Findley

Sorex cinereus ohionensis Bole and Moulthrop.—In their description of this subspecies from Ohio, Bole and Moulthrop (1942:89-95) made no mention of specimens in the United States Biological Surveys Collection from Ellsworth and Milford Center, Ohio, which stand in the literature (see Jackson, 1928:49) as Sorex cinereus cinereus. These two localities lie south of the geographic range ascribed to S. c. ohionensis by Bole and Moulthrop. Examination of the two specimens, United States Biological Surveys Collection, Catalogue No. 70566, and United States National Museum, No. 19434, respectively, both of which are alcoholics, reveals that they are referable to the subspecies ohionensis rather than to S. c. cinereus. This reference is made on the basis of small size, short tail (33 and 31 millimeters, respectively), and fourth upper unicuspid as large as third (the specimen from Milford Center lacks the skull). The occurrence at Milford Center provides a southward extension of known range for S. c. ohionensis of approximately 70 miles. S. c. cinereus seems not to occur in Ohio.

Cryptotis micrura (Tomes).—Davis (1944:376) assigned a Cryptotis from Boca del Rio, Veracruz, to Cryptotis parva berlandieri (Baird). Comparison of this specimen, Texas Cooperative Wildlife Collections, No. 2765, with 8 specimens of C. micrura from various parts of northern Veracruz and with 9 C. parva from southern Tamaulipas reveals that the shrew from Boca del Rio is referable to Cryptotis micrura. The series of 8 specimens in the University of Kansas Museum of Natural History from Altamira, Tamaulipas, provides the southernmost known record of Cryptotis parva berlandieri. These 8 specimens are typical of C. p. berlandieri and show no approach to C. micrura. Average and extreme cranial measurements of 7 specimens from 1 mi. S Altamira are: condylobasal length, 15.6 (15.2-16.1); palatal length, 6.6 (6.4-6.7); maxillary tooth-row, 5.7 (5.4-5.8); cranial breadth, 7.6 (7.4-8.0); least interorbital breadth, 3.5 (3.4-3.7); maxillary breadth, 5.0 (4.8-5.2). Cranial measurements of 8 specimens of C. micrura from various localities in northern Veracruz (1 km. E Mecayucan, 1; 7 km. NNW Cerro Gordo, 3; Teocelo, 2; 7 km. W El Brinco, 1; 5 km. N Jalapa, 1) are: condylobasal length, 17.1 (16.6-17.4); palatal length, 7.1 (6.9-7.4); maxillary tooth-row, 6.2 (5.9-6.4); cranial breadth, 8.5 (8.3-8.6); least interorbital breadth, 3.7 (3.6-4.1); maxillary breadth, 5.3 (5.1-5.6). C. parva and C. micrura may intergrade but a distance of 140 miles separates the geographic ranges as now known of the two kinds and every specimen examined by me is clearly referable to one or the other of the two named kinds and shows no evidence of intergradation.

Notiosorex crawfordi crawfordi Baird.—A specimen in the Museum of Natural History from Jaumave, and one from Palmillas, Tamaulipas, collected by Gerd Heinrich, provide records of the easternmost margin of the range of this species in Mexico. Assignment is made to the subspecies crawfordi on geographic grounds. The two specimens differ from a male from 13 mi. S and 15 mi. W Guadalajara, Jalisco, referred (Twente and Baker, 1951:121) to N. c. evotis (Coues) in slightly larger size; however two skulls from owl pellets from 21 mi. SW Guadalajara, also referred to evotis (loc. cit.), seem to me to differ in no important way from skulls of the Tamaulipan specimens. Measurements of the Tamaulipan specimens, both females, 54932 KU and 54933 KU, are respectively: condylobasal length, —, 16.7; palatal length, —, 7.2; maxillary tooth-row, 6.6, 6.1; cranial breadth, 8.3, 8.1; least interorbital breadth, —, 3.5; maxillary breadth, —, 5.1; total length, 90, 90; tail, 28, 30; hind foot, 11.0, 11.5; ear, 8, 8.

The only other eastern Mexican record of N. crawfordi is based on two skulls from owl pellets collected 3 mi. NW Cuatro Cienegas, Coahuila (Baker, 1953:253).

Sorex oreopolus emarginatus Jackson.—A first-year female Sorex, KU 54346, obtained by Rollin H. Baker from 7 mi. SW Las Adjuntas, 8900 ft., Durango, seems closest, among Mexican shrews that I have examined, to two specimens of S. emarginatus from Plateado, 7600 to 8500 ft., Zacatecas. Measurements of the Las Adjuntas specimen are: total length, 88; tail, 39; hind foot, 13; palatal length, 7.2; maxillary tooth-row, 6.4; maxillary breadth, 4.9; least interorbital breadth, 3.6.

Sorex emarginatus previously was known only from Plateado and the type locality, Bolanos, Jalisco. Comparison of these three specimens with specimens of other species of Mexican shrews of the S. saussurei group leads me to conclude that the group contains two species rather than four as was previously thought. Sorex emarginatus, S. ventralis, and S. oreopolus seem to me to be conspecific. All three nominal species are relatively small, short-tailed shrews. The skulls of the three kinds resemble one another in relatively short rostrum and in dental details. Slight differences in cranial proportions differentiate the three and they should, until more specimens of each are obtained and studied, retain subspecific rank. The specific name, Sorex oreopolus Merriam 1892, should apply to the three kinds since it antedates the names ventralis and emarginatus. The two names last given, therefore, should stand as Sorex oreopolus ventralis Merriam and Sorex oreopolus emarginatus Jackson. The two species, the large S. saussurei, and the small S. oreopolus, as the latter is here understood, occur together over an extensive region in southern Mexico. In other parts of North America a large and a small species of Sorex often occur together in a given area.

The Las Adjuntas specimen was taken only 10 miles southwest of El Salto, Durango, the type locality of S. durangae Jackson. Jackson (1928:101) placed durangae in the Sorex vagrans-obscurus species group, but the two specimens available to him were second year adults with the teeth so much worn that diagnostic characters are not visible on them. I have examined these two specimens (United States Biological Surveys Collection 94539 and 94540) and find that in bodily and cranial proportions they resemble Sorex s. saussurei, and I so assign them.

Sorex milleri Jackson.—Koestner (1941:10) reported 5 Sorex from Cerro Potosi, near La Jolla, Municipio de Galeana, Nuevo Leon, as Sorex emarginatus. Comparison of 4 of these specimens (Chicago Museum of Natural History, 48227, 48228, 48229, 48230) with two S. emarginatus from Plateado, Zacatecas, and specimens of other species of Sorex indicates that the Cerro Potosi shrews differ in many features from emarginatus, but closely resemble, in size and cranial characters, a specimen (F. W. Miller, No. 20) of S. milleri from Sierra del Carmen, Coahuila, and seems to be referable to that species which was not named when Koestner (loc. cit.) recorded his specimen. The range of S. milleri is therefore extended southwestward to western central Nuevo Leon.

Comparison of S. milleri with specimens of other species of North American Sorex leads me to conclude that S. milleri is most closely related to S. cinereus Kerr, and should be included in the S. cinereus group rather than in the S. vagrans-obscurus group. Sorex cinereus and S. milleri are alike, and both differ from even the smallest S. vagrans in relatively long and narrow rostrum, narrow teeth, smaller skull, and in having the third upper unicuspid more often equal to or smaller than, rather than larger than, the fourth unicuspid.

I judge S. milleri to be a relict population of S. cinereus, isolated in the mountains of northeastern Mexico, probably in the late Pleistocene. Sorex cinereus reported from Pleistocene deposits in San Josecito Cave, Nuevo Leon (Findley, 1953:635), probably represents a population ancestral to the modern S. milleri. Sorex milleri should retain specific status because of constant cranial differences from S. cinereus, particularly relatively broader rostrum.

LITERATURE CITED

BAKER, R. H.

1953. Mammals from owl pellets taken in Coahuila, Mexico. Trans. Kansas Acad. Sci., 56:253-254.

BOLE, B. P., and P. N. MOULTHROP.

1942. The Ohio Recent mammal collection in the Cleveland Museum of Natural History. Sci. Publs. Cleveland Mus. Nat. Hist., 5:83-181, September 11.

DAVIS, W. B.

1944. Notes on Mexican mammals. Jour. Mamm., 25:370-403, December 12.

FINDLEY, J. S.

1953. Pleistocene Soricidae from San Josecito Cave, Nuevo Leon, Mexico. Univ. Kansas Publ., Mus. Nat. Hist., 5:635-639, December 1.

JACKSON, H. H. T.

1928. A taxonomic review of the American long-tailed shrews (Genera Sorex and Microsorex). N. Amer. Fauna, 51:I-VI, 1-238, 13 pls., 24 text figs., July 24.

KOESTNER, E. J.

1941. An annotated list of mammals collected in Nuevo Leon, Mexico, in 1938. Great Basin Nat., 2:9-15, February 20.

TWENTE, J. H., and R. H. BAKER.

1951. New records of mammals from Jalisco, Mexico, from barn owl pellets. Jour. Mamm., 32:120-121, February 15.

25-7329

THE END

Home - Random Browse