Integrative taxonomy and evolutionary history reveal cryptic diversity in Myotis riparius (Chiroptera: Vespertilionidae)

Myotis riparius is an insectivorous bat species widely distributed in the Neotropics with evident geographical variation in morphological traits. We conducted an integrative study using mitochondrial DNA, qualitative and quantitative morphology, and current and past species distribution models to investigate the variation, population structure, and distributional limits within M. riparius populations. Phylogenetic inferences indicated that M. riparius is monophyletic, and populations are divided into geographically structured clades that split during the middle Pleistocene. There is no shared haplotype between geographical populations and strong evidence of partial restriction in gene flow. Morphological and morphometric variations revealed subtle distinctions among different populations, but little correspondence with molecular analysis. The distribution models indicated that M. riparius is associated with forest environments, with discontinuity between populations from South American ecoregions. Past distribution modelling, however, indicated that M. riparius had a larger distribution range in the Last Glacial Maximum than currently. Results of modelling and genetic analyses indicated that M. riparius consisted of a large, widespread, and panmictic (meta)population until the middle Pleistocene, when environmental changes driven by climatic dynamics fragmented and isolated the populations. Myotis riparius is here considered a complex of at least four allopatric and parapatric cryptic evolutionary units.