Tshekardocoleidae


Tshekardocoleidae is an extinct family of stem group beetles, known from the Early 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 of Coleoptera in a broad sense. For instance, their elytra are flattened, lack epipleura, 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. The elytra also have remnants of veins, and have rows of "window punctures" between them. Such window punctures are also present in other stem-group beetle families, but in extant beetles are present only in Cupedidae and Ommatidae.

Taxonomy

[file:Tshekardocoleidae larva PIN-1700-4747 fig3A.png|thumb|right|upright|undescribed Tshekardocoleid larvae, Tshekarda site]
Kirejtshuk included the following genera in Tshekardocoleidae
  • †Avocoleus – Obora site ; Moravia, Czech Republic
  • *†Avocoleus fractus
  • *†Avocoleus neglegens
  • †Boscoleus – Obora site ; Moravia, Czech Republic
  • *†Boscoleus blandus
  • †Eocoleus – Obora site ; Moravia, Czech Republic
  • *†Eocoleus scaber
  • †Moravocoleus – Obora site ; Moravia, Czech Republic
  • *†Moravocoleus permianus
  • †Permocoleus – Midco Member ; Noble County, Oklahoma, USA
  • *†Permocoleus wellingtoniensis
  • †Prosperocoleus – Obora site ; Moravia, Czech Republic
  • *†Prosperocoleus prosperus
  • †Retelytron – Obora site ; Moravia, Czech Republic
  • *†Retelytron conopeum
  • †Sylvacoleodes – Tshekarda site ; Suksun, Perm Krai, Russia
  • *†Sylvacoleodes admirandus
  • †Sylvacoleus – Tshekarda site ; Suksun, Perm Krai, Russia
  • *†Sylvacoleus richteri
  • *†Sylvacoleus sharovi
  • †Tshekardocoleus – Tshekarda site ; Suksun, Perm Krai, Russia
  • *†Tshekardocoleus magnus
  • *†Tshekardocoleus minor
  • †Umoricoleus – Obora site ; Moravia, Czech Republic
  • *†Umoricoleus perplex
  • †Votocoleus – Obora site ; Moravia, Czech Republic
  • *†Votocoleus submissus
The genus Uralocoleus had been placed in the family by some authors, but the type species Uralocoleus splendens was considered incertae sedis by Kirejtshuk, 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" ultimus, because it was based on an isolated elytron that could either belong to a beetle or a cockroach. The genus Dictyocoleus, described from the Jurassic and containing only the type species Dictyocoleus jurassicus, was originally placed in the family but was excluded by Kirejtshuk.