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Pleistocene Soricidae from San Josecito Cave, Nuev

Pleistocene Soricidae from San Josecito Cave, Nuevo Leon, Mexico

BY

JAMES S. FINDLEY

University of Kansas Publications Museum of Natural History

Volume 5, No. 36, pp. 633-639 December 1, 1953

University of Kansas LAWRENCE 1953

UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

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

Volume 5, No. 36, pp. 633-639 December 1, 1953

UNIVERSITY OF KANSAS Lawrence, Kansas

PRINTED BY FERD VOILAND, JR., STATE PRINTER TOPEKA, KANSAS 1953

25-265

Pleistocene Soricidae from San Josecito Cave, Nuevo Leon, Mexico

By

JAMES S. FINDLEY

Bones of a large number of vertebrates of Pleistocene age have been removed from San Josecito Cave near Aramberri, Nuevo Leon, Mexico. These bones have been reported upon in part by Stock (1942) and Cushing (1945). A part of this material, on loan to the University of Kansas from the California Institute of Technology, contains 26 rami and one rostrum of soricid insectivores. Nothing seems to be known of the Pleistocene Soricidae of Mexico. The workers cited do not mention them and no shrews are listed by Maldonado-Koerdell (1948) in his catalog of the Quaternary mammals of Mexico. Comparison of these specimens with pertinent Recent material from Mexico, the United States, and Canada leads me to the conclusion that they represent two genera and at least three species. The material examined is described below.

Sorex cinereus Kerr

One right ramus, bearing all three molars but lacking the other teeth and the tip of the coronoid process, needs close comparison only with certain of the smaller North American species of _Sorex_. From _S. merriami_ of southeastern Wyoming, it differs in having a shorter, much shallower dentary, a shorter molar row, and a lower coronoid. In every particular it is identical with _Sorex cinereus_. _Sorex cinereus_ from northern British Columbia and the specimen from Nuevo Leon differ from _Sorex saussurei_, _S. obscurus_, and _S. vagrans_ in the ratio of the height of the coronoid to the length of the dentary. This ratio averages 49.6% in _S. cinereus_ and 53.0% or more (up to 60.0%) in the other species. _Microsorex hoyi_ differs from _S. cinereus_ and from the specimen in question in deeper and shorter dentary, more robust condyle, dentary less bowed dorsally, molars shorter in anteroposterior diameter and higher in proportion to this dimension.

This record, as far as I can determine, constitutes a southward extension of the known Pleistocene or Recent range of this species of approximately 800 miles. The nearest known occurrence of _S. cinereus_ in Recent times is in the mountains of north-central New Mexico. The species now has an extensive range in boreal North America and prefers mesic and hydric communities from which it rarely wanders. I know of no instance of the occurrence of the cinereous shrew in desert areas such as there are between many of the mountain ranges of southern New Mexico, Coahuila, and Nuevo Leon. Therefore, unless the habitat preferences of the species have changed since Pleistocene times, this find constitutes additional evidence that more humid conditions at one time prevailed in the regions mentioned.


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