Taxonomic Relationship Between Sorex Dispar And S. Gaspensis: Inferences From Mitochondrial DNA Sequences

The long-tailed shrew (Sorex dispar) occurs at upper elevations on wooded slopes in the Appalachian Mountains from North Carolina to Quebec. Size in long-tailed shrews is clinal, decreasing from south to north. A closely related species is the slightly smaller Gaspe shrew (Sorex gaspensis), known primarily from the Appalachians farther north in the Gaspe Peninsula of Quebec. Long-tailed shrews captured in northern Maine appear to fit within the size range of the Gaspe shrew which brings up the question: are these specimens small bodied long-tailed shrews at the northern end of their range, Gaspe shrews at the southern edge of their range, or are the 2 species part of the same continuous distribution and, in fact, conspecific? A morphological comparison with other studies indicates that a continuous cline cannot be ruled out. Phylogenetic analysis of mitochondrial DNA d-loop sequences showed that S. gaspensis and S. dispar cluster with no taxonomic or geographic structure, suggesting that they are conspecific.