The evolutionary relationships between ,, ,, ,, and are poorly understood. In order to further explore the evolutionary boundaries of and compare potential taxonomic solutions for this diverse group and its relatives, we conducted phylogenetic analyses of DNA sequence data from alcohol dehydrogenase (1-I2), beta fibrinogen (-I7), interphotoreceptor retinoid-binding protein (3), and cytochrome- (). Phylogenetic analyses of mitochondrial and nuclear genes produced similar topologies although levels of nodal support varied. The best-supported topology was obtained by combining nuclear and mitochondrial sequences. No monophyletic clade was supported. Instead, support was found for a clade containing, ,, ,, and suggesting paraphyly of and confirming previous observations. Our analyses indicated an early divergence of from (approximately 8 million years ago), whereas most other peromyscine taxa emerged within the last 6 million years. To recover a monophyletic taxonomy from and affiliated lineages, we detail 3 taxonomic options in which, ,, , and are retained as genera, subsumed as subgenera, or subsumed as species groups within . Each option presents distinct taxonomic challenges, and the appropriate taxonomy must reflect the substantial levels of morphological divergence that characterize this group while maintaining the monophyletic relationships obtained from genetic data.

Identification of retrotransposon insertions in nonmodel taxa can be technically challenging and costly. This has inhibited progress in understanding retrotransposon insertion dynamics outside of a few well-studied species. To address this problem, we have extended a retrotransposon-based capture and sequence method (ME-Scan [mobile element scanning]) to identify insertions belonging to the Ves family of short interspersed elements (SINEs) across seven species of the bat genus Myotis. We identified between 120,000 and 143,000 SINE insertions in six taxa lacking a draft genome by comparing to the M. lucifugus reference genome. On average, each Ves insertion was sequenced to 129.6 × coverage. When mapped back to the M. lucifugus reference genome, all insertions were confidently assigned within a 10-bp window. Polymorphic Ves insertions were identified in each taxon based on their mapped locations. Using cross-species comparisons and the identified insertion positions, a presence–absence matrix was created for approximately 796,000 insertions. Dollo parsimony analysis of more than 85,000 phylogenetically informative insertions recovered strongly supported, monophyletic clades that correspond with the biogeography of each taxa. This phylogeny is similar to previously published mitochondrial phylogenies, with the exception of the placement of M. vivesi. These results support the utility of our variation on ME-Scan to identify polymorphic retrotransposon insertions in taxa without a reference genome and for large-scale retrotransposon-based phylogenetics.