Status of the Maryland Shrew, <i>Sorex fontinalis</i> Hollister, 1911, based on new morphological and distributional evidence from Pennsylvania and adjacent states

Abstract Using univariate and multivariate statistics, a detailed morphological analysis was conducted on the dentition and skull of long-tailed shrews from east-central United States previously referred to Sorex fontinalis Hollister, 1911, and S. cinereus Kerr, 1792. Based on the examination of 243 shrews, using 25 measurements, these 2 cryptic taxa have parapatric distributions near the border of the Appalachian Mountains and Ridge and Valley physiographic regions in eastern West Virginia, western Maryland, and southwestern Pennsylvania then eastward through central Pennsylvania to the Delaware River, there southward along the Delaware river and bay. Using univariate statistics, about 84% of individuals can be distinguished from each other. Using discriminant function analysis about 98% of individuals are separable with an average jackknife classification error rate of 11%. Both taxa were found within 3 to 54 km of each other at multiple localities without any evidence of morphological intergradation. However, at 1 locality, 5 of 7 specimens collected on the line of parapatry classified as unknowns and appear to have some morphological traits of both species. All morphological and distributional evidence presented is in agreement with those molecular studies that regard S. fontinalis as a distinct species, separate from S. cinereus.