Phylogeny and biogeography of the unique snakefly genus Alena Navás, 1916 (Raphidioptera: Raphidiidae)

The genus Alena Navás, 1916, is considered the most distinct genus of Raphidiidae, because of the uncommon shape of its male genital sclerites and its geographic distribution restricted to the southwestern U.S.A. and western Mexico. Herein, we present a new species of the subgenus Aztekoraphidia U. Aspöck and H. Aspöck, 1970, – Alena (Aztekoraphidia) alanaesp. nov. Based on this discovery we present a detailed morphological study and the first morphological phylogeny of Alena. Our results recover this genus as monophyletic, including the subgenus Aztekoraphidia as sister to a clade composed by the other two monotypic subgenera, Alenas.s. Navás, 1916, and Mexicoraphidia U. Aspöck and H. Aspöck, 1970. We also provide a hypothesis about the biogeographic history of the group, which advocates that species of Alena are strongly associated with central Mexico and their ancestors were probably widely distributed through western North America in the past, of which only a few small groups survived in glacial refuges.