Tshekardocoleidae is an extinct family of

stem group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

beetles, known from the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

. They represent some of the earliest known beetles. They first appeared during the

Cisuralian The Cisuralian, also known as the Early Permian, is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mou ...

, before becoming extinct at the beginning of the

Guadalupian The Guadalupian is the second and middle Series (stratigraphy), series/Epoch (geology), epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico an ...

. A claimed

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

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 In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, an ...

(ancestral characters) of Coleoptera in a broad sense. For instance, their

elytra An elytron (; ; : elytra, ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometime ...

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

upundescribed Tshekardocoleid larvae, Tshekarda site Kirejtshuk (2020) included the following genera in Tshekardocoleidae * †'' Avocoleus'' – Obora site (

Sakmarian In the geologic timescale, the Sakmarian is an age or stage of the Permian period. It is a subdivision of the Cisuralian Epoch or Series. The Sakmarian lasted between 293.52 and million years ago (Ma). It was preceded by the Asselian and fo ...

);

Moravia Moravia ( ; ) is a historical region in the eastern Czech Republic, roughly encompassing its territory within the Danube River's drainage basin. It is one of three historical Czech lands, with Bohemia and Czech Silesia. The medieval and early ...

, Czech Republic **†''Avocoleus fractus'' (

Type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

) **†''Avocoleus neglegens'' * †'' Boscoleus'' – Obora site (

);

, Czech Republic **†''Boscoleus blandus'' (Type species) * †'' Eocoleus'' – Obora site (

);

, Czech Republic **†''Eocoleus scaber'' (Type species) * †'' Moravocoleus'' – Obora site (

);

, Czech Republic **†''Moravocoleus permianus'' (Type species) * †'' Permocoleus'' – Midco Member (

Artinskian In the geologic timescale, the Artinskian is an age (geology), age or stage (stratigraphy), stage of the Permian. It is a subdivision of the Cisuralian Epoch (geology), Epoch or series (stratigraphy), Series. The Artinskian likely lasted between ...

);

Noble County, Oklahoma Noble County is a County (United States), county located in the north central part of Oklahoma. As of the 2020 United States census, 2020 census, the population was 10,924. Its county seat is Perry, Oklahoma, Perry. It was part of the Cherokee ...

, USA **†''Permocoleus wellingtoniensis'' (Type species) * †'' Prosperocoleus'' – Obora site (

);

, Czech Republic **†''Prosperocoleus prosperus'' (Type species) * †'' Retelytron'' – Obora site (

);

, Czech Republic **†''Retelytron conopeum'' (Type species) * †'' Sylvacoleodes'' – Tshekarda site (

Kungurian In the geologic timescale, the Kungurian is an age or stage of the Permian. It is the latest or upper of four subdivisions of the Cisuralian Epoch or Series. The Kungurian lasted between and million years ago (Ma). It was preceded by the Arti ...

);

Suksun Suksun () is an urban locality (a work settlement) and the administrative center of Suksunsky District of Perm Krai, Russia, located on the left bank of the Sylva River (a tributary of the Chusovaya River), from the city of Perm. Population: ...

Perm Krai Perm Krai (, ; ) is a federal subjects of Russia, federal subject of Russia (a Krais of Russia, krai), located in Eastern Europe. Its administrative center is Perm, Russia, Perm. The population of the krai was 2,532,405 (2021 Russian census, 2021 ...

, Russia **†''Sylvacoleodes admirandus'' (Type species) * †'' Sylvacoleus'' – Tshekarda site (

);

, Russia **†''Sylvacoleus richteri'' (Type species) **†''Sylvacoleus sharovi'' * †'' Tshekardocoleus'' – Tshekarda site (

);

, Russia **†''Tshekardocoleus magnus'' (Type species) **†''Tshekardocoleus minor'' * †'' Umoricoleus'' – Obora site (

);

, Czech Republic **†''Umoricoleus perplex'' (Type species) * †'' Votocoleus'' – Obora site (

);

, Czech Republic **†''Votocoleus submissus'' (Type species) The genus '' Uralocoleus'' had been placed in the family by some authors, but the type species ''Uralocoleus splendens'' was considered ''

incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

'' 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''" ''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 (2020).

References

{{Taxonbar, from=Q19393435

† A dagger, obelisk, or obelus is a typographical mark that usually indicates a footnote if an asterisk has already been used. The symbol is also used to indicate death (of people) or extinction (of species or languages). It is one of the mo ...

Prehistoric beetles Taxa named by Boris Rohdendorf Tshekardocoleoidea Prehistoric insect families Cisuralian animals