A new species of mastiff bat (Chiroptera, Molossidae, Molossus) from Guyana and Ecuador

We describe a new species of mastiff bat in the genus Molossus (Molossidae), which was previously confused with the common and widely distributed M. molossus, from Guyana and Ecuador based on morphological and molecular differences. It is diagnosed by the following set of morphological characteristics: bicolored dorsal pelage, rounded anterior arch of the atlas, triangular occipital bone, and smaller body and skull size. In a molecular phylogenetic analysis of mitochondrial and nuclear DNA, maximum likelihood and parsimony trees recovered eight clades in the genus and a polyphyletic relationship for the M. molossus species complex. The new species was recovered in a well-supported clade that can be genetically distinguished from other species in the genus by its high level of sequence divergence based on the mitochondrial CO1 gene (8.0-10.1%) and on the nuclear gene beta fibrinogen (1.0-3.1%). It is broadly sympatric with M. molossus sensu stricto in northern South America, but morphologically distinct and genetically divergent.