Tshekardocoleidae is an extinct family of stem group beetles, known from the Permian. They represent some of the earliest known beetles. They first appeared during the Cisuralian, before becoming extinct at the beginning of the Guadalupian.[2] A claimed Jurassic record is doubtful.[1] Like other primitive beetles, they are thought to have been xylophagous.[2] The oldest known beetle, Coleopsis, was originally assigned to this family, but is now assigned to its own family Coleopsidae.[1]
The Tshekardocoleidae are thought to have retained several plesiomorphies (ancestral characters) of Coleoptera in a broad sense. For instance, their elytra are flattened, lack epipleura (outer margins), cover the body loosely, and their tips extend beyond the apex of the abdomen. Their abdomens have a nearly cylindrical shape and are thought to have been flexible, apparently being able to strongly contract and expand. In extant beetles, the elytra are tight-fitting, forming a subelytral space which is absent in Tshekardocoleidae.[3]
The genus Uralocoleus had been placed in the family by some authors, but the type species Uralocoleus splendensZalessky 1947 was considered incertae sedis by Kirejtshuk (2020), as the type specimen is in bad condition and cannot be reliably compared with other members of the family, and the second species placed in the genus "Uralocoleus" ultimus was rejected from placement in Uralocoleus and listed as "genus incertus" ultimusPonomarenko, 2000, because it was based on an isolated elytron that could either belong to a beetle or a cockroach.[1] The genus Dictyocoleus, described from the Jurassic and containing only the type species Dictyocoleus jurassicusHong, 1982, was originally placed in the family but was excluded by Kirejtshuk (2020).[1]
