Revision of the genus Philolithus (Coleoptera: Tenebrionidae)

Philolithus (Pimeliinae: Asidini) species are large beetles endemic to arid environments in western North America and the genus presently contains 22 species in five subgenera. Little is known about the biology of Philolithus species but some are known to exhibit mass emergences after rainfall and others have been observed laying eggs in nests of harvester ants (Pogonomyrmex spp.). Over the years the species composition of Philolithus has expanded and contracted wherein historically, a total of 39 different species have been synonymized into the 22 presently valid Philolithus species. Recent work on Philolithus has focused at the generic level or on correcting synonyms from the taxonomically problematic work of Thomas Casey Jr., but not on relationships within the genus or potential new taxa. Because of these extensive synonymies, information on Philolithus composition and species identity is scattered, much of which is outdated or invalid. There is no single modern dichotomous key to identifying Philolithus species either. We are striving to revise the genus and reconstruct a robust Philolithus phylogeny through extensive morphological character examination and the creation of morphological matrices to present the first updated phylogeny for Philolithus. This includes presenting several newly identified species and proposing synonymies of currently valid species within the group.