Tshekardocoleidae

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. A claimed Jurassic record is doubtful. Like other primitive beetles, they are thought to have been xylophagous. The oldest known beetle, Coleopsis, was originally assigned to this family, but is now assigned to its own family Coleopsidae.

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.

Taxonomy
Kirejtshuk (2020) included the following genera in Tshekardocoleidae


 * †Avocoleus Ponomarenko, 1969 – Obora site (Permian Sakmarian ); Moravia, Czech Republic
 * †Avocoleus fractus (Kukalová, 1969) (Type species)
 * †Avocoleus neglegens (Kukalová, 1969)
 * †Boscoleus Kukalová, 1969 – Obora site (Permian Sakmarian ); Moravia, Czech Republic
 * †Boscoleus blandus Kukalová, 1969 (Type species)
 * †Eocoleus Kukalová, 1969 – Obora site (Permian Sakmarian ); Moravia, Czech Republic
 * †Eocoleus scaber Kukalová, 1969 (Type species)
 * †Moravocoleus Kukalová, 1969 – Obora site (Permian Sakmarian ); Moravia, Czech Republic
 * †Moravocoleus permianus Kukalová, 1969 (Type species)
 * †Permocoleus Lubkin & Engel, 2005 – Midco Member (Permian, Artinskian ); Noble County, Oklahoma, USA
 * †Permocoleus wellingtoniensis Lubkin & Engel, 2005 (Type species)
 * †Prosperocoleus Kukalová, 1969 – Obora site (Permian Sakmarian ); Moravia, Czech Republic
 * †Prosperocoleus prosperus Kukalová, 1969 (Type species)
 * †Retelytron Kukalová, 1965 – Obora site (Permian Sakmarian ); Moravia, Czech Republic
 * †Retelytron conopeum Kukalová, 1965 (Type species)
 * †Sylvacoleodes Ponomarenko, 1963 – Tshekarda site (Permian Kungurian ); Suksun, Perm Krai, Russia
 * †Sylvacoleodes admirandus Ponomarenko, 1963 (Type species)
 * †Sylvacoleus Ponomarenko, 1963 – Tshekarda site (Permian Kungurian ); Suksun, Perm Krai, Russia
 * †Sylvacoleus richteri Ponomarenko, 1963 (Type species)
 * †Sylvacoleus sharovi Ponomarenko, 1963
 * †Tshekardocoleus Rohdendorf, 1944 – Tshekarda site (Permian Kungurian ); Suksun, Perm Krai, Russia
 * †Tshekardocoleus magnus Rohdendorf, 1944 (Type species)
 * †Tshekardocoleus minor Ponomarenko, 1963
 * †Umoricoleus Kukalová, 1969 – Obora site (Permian Sakmarian ); Moravia, Czech Republic
 * †Umoricoleus perplex Kukalová, 1969 (Type species)
 * †Votocoleus Kukalová, 1969 – Obora site (Permian Sakmarian ); Moravia, Czech Republic
 * †Votocoleus submissus Kukalová, 1969 (Type species)

The genus Uralocoleus had been placed in the family by some authors, but the type species Uralocoleus splendens Zalessky 1947 was considered incertae sedis by Kirejtshuk (2020) as a possible beetle or cockroach. The second species placed in the genus "Uralocoleus" ultimus was rejected from placement in Uralocoleus and listed as "genus incertus" ultimus Ponomarenko, 2000. The genus Dictyocoleus, described from the Jurassic and containing only the type species Dictyocoleus jurassicus Hong, 1982, was originally placed in the family but was excluded by Kirejtshuk (2020).