Trachypachidae

The Trachypachidae (or sometimes false ground beetles) are a family of beetles that generally resemble small ground beetles, but that are distinguished by the large coxae of their rearmost legs. There are only six known extant species in the family, with four species of Trachypachus found in northern Eurasia and northern North America, and two species of Systolosoma in Chile. They were much more diverse in the past, with many members belonging to the extinct subfamily Eodromeinae, the first fossils known of this family are of the genera Petrodromeus and Permunda from the Permian-Triassic boundary of Russia. Their habits are similar to those of the ground beetles; they are usually found in the leaf litter of conifer forests. To quote G. E. Ball, 'the most interesting thing about this small family is its uncertain phylogenetic relationships'; it has been classified as a subfamily of Carabidae, and as a family been placed in several different positions relative to other beetle families. L. Strada, M. Montagna, and A. Tintori. 2014. A new genus and species of the family Trachypachidae (Coleoptera, Adephaga) from the upper Ladinian (Middle Triassic) of Monte San Giorgio. Rivista Italiana di Paleontologia e Stratigrafia 120:183-190