Two New Meadow Mice from Michoacán Mexico   By: E. Raymond (Eugene Raymond) Hall (1902-1986)

BY

E. RAYMOND HALL

University of Kansas Publications Museum of Natural History

Volume 1, No. 21, pp. 423 427, 6 figs. in text December 24, 1948

University of Kansas LAWRENCE 1948

UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

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

Volume 1, No. 21, pp. 423 427, 6 figs. in text December 24, 1948

UNIVERSITY OF KANSAS Lawrence, Kansas

PRINTED BY FERD VOILAND, JR., STATE PRINTER TOPEKA, KANSAS 1948

22 3717

Two New Meadow Mice from Michoacán, Mexico

By

E. RAYMOND HALL

In preparing a list of kinds of mammals of which specimens have been saved from the Méxican state of Michoacán, two heretofore unrecognized subspecies of the Méxican meadow mouse, Microtus mexicanus , have been found. Names for these and descriptions are given below.

Microtus mexicanus fundatus new subspecies

Type. Male, adult, skin and skull; No. 100637, Univ. California Mus. Vert. Zool.; 3 1/2 mi. S Pátzcuaro, 7,900 ft., Michoacán, México; March 9, 1943; obtained by E. R. Hall, original no. 5882.

Range. Known only from the vicinity of the type locality.

Diagnosis. Size large (see measurements); color brown overlain with cinnamon; nasals expanded distally with premaxillary borders concave laterally; posterior border of orbit inclined posterolaterally; preorbital region and interparietal region depressed; incisive foramina narrow; zygomatic arches parallel; tympanic bullae much inflated.

Comparisons. Among named subspecies of Microtus mexicanus , M. m. fundatus most closely resembles M. m. mexicanus but differs as follows: Larger in all parts measured; pelage with slightly less buffy color and with the buffy color that is present of a slightly lighter tint; posterior two thirds of premaxillary border of each nasal concave rather than straight; posterior border of orbit forming more acute angle with sagittal plane of posterior part of skull; superior outline of nasals straight rather than depressed in posterior part; tympanic bullae more inflated both in vertical and horizontal planes.

From M. c. salvus , the subspecies next to the westward, fundatus differs as follows: Averaging larger in all parts measured; less reddish on upper parts; underparts with more reddish color but the reddish of lighter tint; perineal region buffy instead of plumbeous; nasals with premaxillary borders laterally concave rather than straight; superior outline of skull with nasal segment sloping anteroventrally and interparietal segment sloping posteroventrally rather than straight; posterior margin of orbit inclined posterolaterally thus forming an acute angle, instead of a right angle, with sagittal plane of braincase; zygomatic arches parallel rather than bowed outward; incisive foramina narrower; tympanic bullae more inflated in vertical plane.

Relying on Bailey's (N. Amer. Fauna, 17:55, 1900) description of Microtus fulviventer , fundatus differs in much larger tympanic bullae.