Abstract
In this study, we aim to understand the boundaries and the species evolutionary relationships in Mesochila, which includes 20 species arranged into three subgenera. We also conducted a biogeographic analysis that allowed us to identify the major events that shaped the currently disjunct distribution of the group. Our analyses were performed employing four major phylogenetic algorithms: equal and implied weight parsimony, maximum likelihood and Bayesian inference. Phylogenetic analyses, including 25 taxa (all 20 species in the genus plus five outgroups) and 37 characters, indicated that Mesochila is a monophyletic group composed of four strongly supported lineages, although no consensus was attained regarding relationships between lineages. Bayesian inference resulted in the less resolved topology, whereas implied weight parsimony yielded the most different tree when using a low k value (1). We present a new infrageneric classification for the group with the description of Mesochila (Neomesochila)subgen. nov. to accommodate M. (N.) brevipennis, M. (N.) drechseli, M. (N.) moraveci, and M. (N.) prepusula. Furthermore, we transfer M. (M.) distincta from M. (Eumesochila) back to M. (Mesochila). The biogeographical analysis suggested a South American origin for the group, in Chacoan/Paraná dominions (Atlantic rainforest/Cerrado biomes), with subsequent dispersions to Central America and Amazonia.