Cryptic diversity in Andrognathus corticarius Cope, 1869 and description of a new Andrognathus species from New Mexico (Diplopoda, Platydesmida, Andrognathidae)

Andrognathus is a genus of small, thin-bodied millipedes found in deciduous forests of North America. Poorly understood, these organisms inhabit decaying wood and have morphologically conserved and difficult-to-identify sexual characters that have limited study historically. Recent use of scanning electron microscopy has uncovered variation in male genitalia that was previously unknown in the genus. The distribution of Andrognathus and the extent of this variability across the continent, however, were undocumented, and a wealth of natural history collections remained uncatalogued. Here a new species of Andrognathus is described from New Mexico, Andrognathus grubbsi sp. n., natural history collections are utilized to create a comprehensive map of the genus, and a neotype established for the type species, Andrognathus corticarius Cope, 1869. Analysis of the cytochrome oxidase I gene (COI) for A. corticarius was completed for the type series and individuals across the species distribution, but little variation was found. Andrognathus grubbsi sp. n. joins A. corticarius and A. hoffmani Shear & Marek, 2009 as the only members of the genus.