Mensural Discrimination of Four Species of 

 Perotnyscus (Rodentia: Muridae) in the Southeastern 



United States 



Joshua Laerm 



Museum of Natural History, University of Georgia, Athens, 

 Georgia 30602 



AND 



James L. Boone 



Museum of Natural History, Institute of Ecology, and Savannah River 

 Ecology Laboratory, University of Georgia, Athens, Georgia 30602 



ABSTRACT — We subjected 17 mensural characters from a total 

 of 460 cotton mice (Peromyscus gossypinus), white-footed mice 

 (P. leucopus), deer mice (P. maniculatus), and old-field mice 

 (P. polionotus) to discriminant analysis to maximally distinguish 

 among specimens of these species in the southeastern United 

 States. If external measurements are available, 13 characters are 

 necessary to correctly classify all specimens. If external measurements 

 are not available, 14 cranial characters discriminate at most 91% 

 of the specimens. In pairwise comparisons using external and 

 skull measurements, at least 98% of specimens can be separated 

 with one or two characters. In pairwise comparisons (except P. 

 leucopus-P. maniculatus) using only skull measurements, at least 

 95% of specimens can be correctly identified to species with 

 one or two characters. For P. leucopus and P. maniculatus, six 

 characters correctly separate 86% of the specimens, and two characters 

 separate 82%. 



White-footed mice {Peromyscus, Golger) are among the most 

 widely distributed and ubiquitous North American mammals (Hall 1981), 

 are the most broadly studied native mammals (King 1968), and are 

 represented extensively in systematic collections. Despite their 

 commonness and familiarity to most biologists, it is still difficult to 

 distinguish among species when we use morphological characters 

 (Hooper 1968). Much literature has resulted from regional attempts to 

 provide for mensural discrimination among Peromyscus, especially 

 between and within Osgood's (1909) maniculatus and leucopus species- 

 groups. Papers have been published separating the white-footed mouse 

 (P. leucopus [Rafinesque]), from the deer mouse (P. maniculatus [Wagner]) 

 in New England (Choate 1973), Kansas (Choate et al. 1979), Wisconsin 

 (Stromberg 1979), and Maryland (Feldhamer et al. 1983); separating 

 the white-footed mouse from the cotton mouse (P. gossypinus [Le Conte]), 

 in Alabama (Linzey et al. 1976) and eastern Texas (Engstrom et al. 



Brimleyana 21:107-123, December 1994 1.07 



