The Subspecies of the Mexican Red-bellied
Squirrel, Sciurus aureogaster

BY

KEITH R. KELSON

University of Kansas Publications
Museum of Natural History
Volume 5, No. 17, pp. 243-250
April 10, 1952

University of Kansas
LAWRENCE
1952

University of Kansas Publications, Museum of Natural History

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

Volume 5, No. 17, pp. 243-250
April 10, 1952


University of Kansas
Lawrence, Kansas

PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1952

24-2174

The Subspecies of the Mexican Red-bellied
Squirrel, Sciurus aureogaster

BY

KEITH R. KELSON

In his excellent taxonomic treatment of the tree squirrels of Mexico and Central America, Nelson (Proc. Washington Acad. Sci., 1:15-110, 2 pls., May 9, 1899) recognized three subspecies of red-bellied squirrels, Sciurus aureogaster aureogaster F. Cuvier, Sciurus aureogaster hypopyrrhus Wagler, and Sciurus aureogaster frumentor Nelson. In his lists of specimens examined, Nelson (op. cit.:42 and 44) assigned certain specimens from "mountains near Santo Domingo" and Guichicovi in Chiapas, and Catemaco in Veracruz, to S. a. aureogaster, and other specimens from the same localities to S. a. hypopyrrhus. I originally attempted to study (identify to subspecies) the series of animals from only three places, but it became evident that a more extensive study was indicated.

The locality whence the holotype of Sciurus aureogaster aureogaster was obtained is unknown. Because certain specimens from Altamira, Tamaulipas, closely resemble Cuvier's figure of the type, Nelson (op. cit.:41) subsequently designated Altamira as the type locality. Miniatitlan, Veracruz, was designated by Nelson as the type locality of S. a. hypopyrrhus because Wagler's description of the type of that subspecies fitted so well certain of Nelson's specimens from that place.

Sciurus a. hypopyrrhus was said by Nelson (op. cit.:43 and 44) to differ from S. a. aureogaster in darker color, thinner pelage, much stiffer and more shining dorsal hairs, slenderer tail with black predominating, larger and proportionately narrower skull with larger auditory bullae, each bulla being "slightly constricted just in front of middle." Sciurus aureogaster varies greatly in intensity of color and in color-pattern. Fully 30 per cent of the specimens examined are in some degree melanistic and approximately 20 per cent of them are completely so. Others are more or less brown; the brown dulls the usually rufous parts. In many specimens this brown is well distributed even in the otherwise grizzled areas; in some specimens it is evenly distributed and in others it is in patches. Indeed, scarcely any two "normally" colored specimens are alike. Typically, the intense rufous color characteristic of the underparts in both S. a. aureogaster and S. a. hypopyrrhus is also present on the costal region and shoulders. Even this distribution of color is highly variable; some specimens (for example No. 23948 KU, from 3 km. E San Andres Tuxtla, Veracruz) show no rufous dorsally and others (for example No. 19307 KU, from 20 km. W Piedras Negras, Veracruz) have the rufous extending over the legs, sides, and almost all of the dorsum from the shoulders to the rump except (in some) for an interrupted