Taxonomic Background of Nocturnal Sphaeropthalmini
Of the three New World subfamilies of Mutillidae, all Nearctic nocturnal mutillids belong to the subfamily Sphaeropthalminae. Furthermore, Sphaeropthalminae is split into two tribes, Dasylabrini, which is found in the Old World, and Sphaeropthalmini, which is found in the New World and Australia (Brothers 1975). Nearctic nocturnal mutillids are placed in the tribe Sphaeropthalmini. The nocturnal mutillids represent nearly half of the known Nearctic species and are classified in the genera Acanthophotopsis, Acrophotopsis, Dilophotopsis, Odontophotopsis, Photomorphus, and Sphaeropthalma. These are endemic to the Nearctic region, being found throughout the North America, Mexico, and, to a lesser extent, further south in Central America. Exceptions to this distribution are several species (mostly undescribed) of Sphaeropthalma that are Neotropical. Several other Sphaeropthalmini mutillids species of Limaytilla Casal, Scaptodactyla Burmeister (both from Argentina), and many species of several undescribed genera from Chile and Argentina are nocturnal.
Schuster (1958) performed the only extensive study of the nocturnal male Sphaeropthalmini. He described 128 species of nocturnal Sphaeropthalmini, created three new genera (Acanthophotopsis, Acrophotopsis and Dilophotopsis) and six new sub-genera (Periphotopsis, Photomorphina, Xenomorphus, Physetapsis, Photopsioides, and Xenophotopsis) based on males only. Unfortunately, there are undeniable problems with Schuster’s treatment of the genera.
Difficulties with Schuster's Revision
Odontophotopsis villosa Mickel - undescribed female