Mensural Discrimination of Sorex longirostris and Sorex 



cinereus (Insectivora: Soricidae) in the Southeastern 



United States 



Joshua Laerm, Michael A. Menzel, and James L. Boone 



Museum of Natural History, Institute of Ecology, and 



Daniel B. Warnell School of Forest Resources, 



University of Georgia, Athens, Georgia 30602 



ABSTRACT — The effectiveness of univariate and multivariate statistics 

 in distinguishing Sorex cinereus and S. longirostris from the southeastern 

 United States on the basis of standard body and cranial measure- 

 ments was assessed. Eleven of 15 characters in univariate comparisons 

 showed significant differences between species, but the range of measure- 

 ments overlapped. Bivariate comparisons permit identification us- 

 ing external measurements, cranial and external measurements combined, 

 and cranial measurements alone. Multivariate procedures permitted 

 maximum distinction of the species. A discriminant function model 

 is presented to permit identification on the basis of three cranial 

 characters. 



The masked shrew (Sorex cinereus Kerr 1792) is distributed throughout 

 the transcontinental coniferous forests of North America from the Canadian 

 Arctic south into the extreme northern portions of the United States 

 with extension into the montane forests of the Rocky and Appalachian 

 mountains (Hall 1981, Junge and Hoffmann 1981, van Zyll de Jong 

 and Kirkland 1989, Laerm et al. 1995). The southeastern shrew (Sorex 

 longirostris Bachman 1837) ranges from northern Missouri east through 

 the southern portions of Illinois, Indiana, and Ohio to Maryland, and 

 southward from eastern Oklahoma to Florida (French 1980a, 19806; 

 Hall 1981; Junge and Hoffmann 1981; and Jones et al. 1991). The 

 two species have overlapping distributions in northcentral Missouri 

 (Mock and Kivett 1980, Schwartz and Schwartz 1981, Greer 1989), 

 southern Illinois (Hoffmeister 1989) and Indiana (Mumford and Whitaker 

 1982), and throughout much of the southern Appalachians from West 

 Virginia and Virginia south to Georgia and South Carolina (Hall 1981, 

 Pagels and Handley 1989, Jones et al. 1991, Ford et al. 1994, Laerm 

 et al. 1995). 



Sorex cinereus and S. longirostris are morphologically remarkably 

 similar. The two are reported to differ in that cinereus is somewhat 

 larger, has a longer tail (usually more than 31 mm), a comparatively 

 longer and more slender rostrum, a higher braincase, and third unicuspids 



Brimleyana 24:15-27 April 1997 15 



