Biochemical Systematics of North American Moles (Insectivora: Talpidae)

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Abstract
Genetic variation within and among five genera and seven species of North American moles of the family Talpidae was examined using starch-gel electrophoresis. All loci examined, except LAP, were found to segregate for more than one allele among species, with a maximum of eight different alleles at any single locus. Average heterozygosity values (H̄) ranged from 0.00 to 0.015 in fossorial genera and up to 0.050 in the semifossorial Neurotrichus gibbsii. Allozymic data suggest that the Recent North American talpid fauna comprises two separate groups. These findings support the contention of Cabrera (1925) that the North American moles are most appropriately considered as two distinct subfamilies: the Condylurinae, including only the genus Condylura; and the Scalopinae, consisting of Scalopus, Neurotrichus, Parascalops, and Scapanus. Formal recognition of these subfamilies, however, must await Old World comparisons. Genetic similarity among genera excluding Condylura ranged from a low Roger's similarity value (S) of 0.28 between Scalopus and Parascalops to a high of 0.57 between Scapanus orarius and Neurotrichus, with the average S across genera being 0.46. These data suggest that Parascalops and Scapanus shared a common ancestor after the divergence of Scalopus. The allozymic data provided an estimated divergence time of from 25 to 38 million years BP for this dichotomy, and 49 million years for the divergence between Condylura and other North American genera.