Evolutionary Relationships Among Subspecies of the Eastern Mole (scalopus Aquaticus) in the Central United States

Abstract

Scalopus aquaticus, commonly known as the eastern mole, is native to the eastern U.S. with populations extending into southern Canada and northern Mexico. Yates and Schmidly (1977) used morphometrics to study individuals from the central U.S., and Hall (1981) reported that 16 subspecies were recognized at the time. Here, we used cytochrome b sequence data to evaluate the genetic differences of 7 S. aquaticus subspecies to examine if geographical barriers within the central U.S. affect the gene flow of this species. We sequenced 465 base pairs of the cytochrome b gene from 36 museum specimens collected throughout the central U.S. Both neighbor joining and maximum likelihood methods, following a Tamura3 + G model of evolution and 1,000 bootstrap replicates, suggest there is genetic support for only 2 of these 7 S. aquaticus subspecies. Two specimens from Louisiana form a separate group from all other specimens in the central U.S. The validity of the subspecies in Louisiana, S. aquaticus howelli, was also supported with an average genetic distance of 5.8% when compared to any other specimen. Pairwise genetic distances between all other moles averaged 2.3%. Our results, using cytochrome b DNA sequences, are similar to those of a previous unpublished student thesis using D loop sequences. Together these studies suggest high levels of gene flow among moles throughout the central U.S. and call into question the taxonomic status of many S. aquaticus subspecies.