Placement of the rediscovered Myotis planiceps (Chiroptera: Vespertilionidae) within the Myotis phylogeny

Abstract

Myotis planiceps (flat-headed myotis) was known from only 3 specimens collected from 3 different sites in the states of Coahuila, Nuevo Leon, and Zacatecas, Mexico, since its discovery in 1952. The last specimen was collected in 1970; in 1996, after efforts to recollect samples failed, the species was listed as extinct. However, an expedition in 2004 rediscovered a population of M. planiceps and the species was relisted as endangered. Members of this species have a conspicuously flattened cranium, speculated to be an adaptation for living in crevices; however, little is known about its biology and, to date, little work has been done to clarify its phylogenetic relationships with other members of the genus Myotis. In order to elucidate the placement of M. planiceps within the Myotis phylogeny, we sequenced 1,140 base pairs (bps) of the mitochondrial cytochrome-b gene (Cytb) and 1,148 bps of the nuclear Recombination Activating Gene 2 (rag2) from 7 samples collected from 4 different localities in north-central Mexico. We found 4 different haplotypes for Cytb that differed by 0.14% mean sequence divergence and 13 alleles for rag2 within samples of M. planiceps. We performed maximum parsimony, maximum likelihood, and Bayesian analyses to compare these samples with Myotis sequences available on GenBank. All reconstructions placed M. planiceps within a strongly supported clade including several Nearctic Myotis (M. volans, M. sodalis, M. lucifugus, M. thysanodes, and M. evotis). M. planiceps forms a paraphyletic relationship with M. volans, despite significant differences in skull morphology between the 2 species.