The Stasis and Possible Patterns of Selection in Evolution of a Group of Related Species from the Bat Genus Myotis (Chiroptera, Vespertilionidae)

Abstract

Phenotypic evolutionary rates were measured for craniometric characters in five extant closely related OTUs from the bat genus Myotis (Chiroptera, Vespertilionidae): M. myotis, M. blythii oxygnathus, M. b. omari, M. b. blythii, and M. nattereri using Lynch’s and Gingerich’s approaches. Cranial shape appeared to be more conservative than cranial size. Estimates for evolutionary rates were found to be lower than expected if the divergence had been produced solely by mutation and random drift. So, it can be concluded that stabilizing selection was the principal factor that maintained craniometric characters during the evolution of the studied species and prevented their greater diversification. The observed differences between the OTUs could be established by random drift or directional selection of rather moderate intensity. The rates of divergence between the ancestors of M. nattereri and the common ancestors of M. blythii and M. myotis apparently were higher than the rates of following divergence between M. myotis, M. b. oxygnathus, M. b. omari and M. b. blythii.