Abstract
Nongeographic and geographic variation in mainland forms of the cactus mouse (Peromyscus eremicus) was assessed utilizing 13 cranial characters. The total sample (9932 specimens from over 2000 individual localities) was divided into 175 grouped localities and 72 quadrat localities (the latter determined by a 150 km grid system) for alternative considerations of geographic variation employing both univariate and multivariate analyses. The patterns of variation obtained using each grouping scheme are described herein. Three distinct subspecies of P. eremicus (eremicus, fraterculus, and sinaloensis) are formally recognized. The relationship of the observed pattern of variation to seven environmental variables was examined using multiple regression analysis. Four variables (mean January temperature, mean July temperature, longitude, and elevation) explained significant portions of the variation in an overall size factor. These variables appeared to affect overall size in manner contrary to that expected from Bergmann's rule. A possible explanation, in concert with predictions expected from Bergmann's rule, is offered.
Legg, Richard George (1978). Geographic variation in the cactus mouse, Peromyscus eremicus (Rodentia: Muridae). Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -297617.