Islands in the stream: Distribution of Myotis attenboroughi (Chiroptera, Vespertilionidae) in Grenada and mainland South America illuminates the evolutionary history of Caribbean Myotis

Myotis attenboroughi was recently described based on specimens from Tobago Island and considered an endemic species until now. Based on morphological and molecular data, we extended its occurrence to Grenada and Suriname. The presence of M. attenboroughi in Grenada, Tobago and mainland South America can be explained by the intermittent connections between these islands and the continent during the Plio-Pleistocene glaciations. However, our analyses recovered an Myotis individual from Grenada phylogenetically related to Myotis nyctor from Barbados, although it is morphologically like the other specimens of M. attenboroughi , revealing a surprising incongruence between genotype and phenotype. Barbados is a geologically recent island and historically unconnected with other Caribbean islands or with South America. We hypothesized that the invasion of the M. nyctor lineage from Barbados to Grenada was the result of an extreme overwater dispersal, perhaps driven by wind streams during tropical storms. Subsequently, introgression of lineages may have occurred through hybridization, which can explain the discordance between the phenotype (like M. attenboroughi ) and the genotype (like M. nyctor ) of this specimen. Additional comments on the formation of the Caribbean Myotis assemblage are presented from the perspective of new evolutionary discoveries for this genus.