Limitations of Mitochondrial Cytochrome-b Gene in Resolving Phylogenetic Relationships within the Genus Myotis Kaup, 1829

Despite being one of the most widespread bat genera worldwide, Myotis Kaup, 1829 is a highly problematic group from a systematic perspective. In this study, several genetic characteristics (nucleotide composition and transition/transversion rate) of this genus were determined through mitochondrial Cytochrome-b region analyses and phylogenetic relationships between species were evaluated. The obtained Bayesian Inference tree did not comply with the literature, with pairwise distances between species ranging from 1.4% to 21%. The low genetic distance between Myotis yumanensis and Myotis velifer (1.4%) suggests that these two species must be re-evaluated taxonomically. Some species belonging to the Myotis mystacinus, Myotis nigricans, and Myotis nattereri species complexes were also located in different branches. Furthermore, Myotis martiniquensis sequences did not cluster in the Bayesian Inference tree and low posterior probability values were observed on some branches. These findings indicate that the CYTB gene may have limited resolution when used alone to reconstruct phylogenetic relationships within Myotis. Therefore, the integration of mitochondrial and nuclear markers may provide more robust insights into the phylogeny of this genus.