Genus-level review of pocket gophers in the family Geomyidae

Abstract

Pocket gophers (Geomyidae) comprise a well-studied family at the species level but need an updated revision at the generic level because studies of each genus have applied different data sets and different criteria for recognizing distinct taxa.  Pocket gophers thrive from temperate Canada south to Panama and Colombia, where they inhabit various habitats, including temperate forests, prairies, steppes, hot and cold deserts, and subtropical and tropical areas.  The taxonomy at the genus and species levels underwent many changes in the early twenty-first century due to use of different sequencing methodologies.  This article builds upon those analyses to review genus-level relationships within the Geomydae.  Specifically, we analyzed the sequences available in Genbank for members of the family Geomyidae (Cytb for 47 species and COI for 33 species).  We conducted different phylogenetic analyses; in all cases, genera were classified into monophyletic groups associated with the tribes Geomyini and Thomomyini.  In the Thomomyini, the genus Thomomys was recognized with two genera, Megascapheus and Thomomys, which are more genetically distinct than many other genera.  In the Geomyini, each genus and subgenus are distinct monophyletic groups with very strong support and large p-distances.  The Mississippi River appears to function as an important geographic barrier within Geomys, with marked genetic differentiation between populations on the eastern and western sides of the river.  Collectively, our analyses based on mtDNA sequences suggest that a more detailed revision employing multiple data sets is needed for the genera within the Geomyidae.