Molecular phylogeny of the riffle beetle genus Hexanchorus revealed a presence of a new genus (Coleoptera: Elmidae)

The riffle beetle genus Hexanchorus Sharp is, with 25 known species, the most speciose genus of the subfamily Larainae in the Neotropics and the second largest globally. An analysis of its phylogeny, based on two mitochondrial (COI, 16S) and two nuclear (18S, 28S) markers, including Hexanchorus-like, but morphologically distinct specimens, supported presence of an unknown genus. The new genus, Rumilara gen. nov., is described here with four new species (R. obscura sp. nov., R. paterna sp. nov., R. riberai sp. nov., R. suppressa sp. nov.) and their larvae. The separate position of the new genus is, beside molecular differences, well substantiated by the morphology of adults (the absence of sexual dimorphism, structure of the pronotum) and larvae (pleurites never reaching to sixth abdominal ventrite). H. sagittatus stat. nov. is elevated to species rank based on molecular data, and Rumilara leleupi (Delève) comb. nov. is transferred from the genus Hexanchorus and redescribed, based on its morphology