Micromalthidae is an ancient family of small beetles belonging to the suborder Archostemata. The only known living representative is the telephone-pole beetle, Micromalthus debilis. A few extinct species have been described, the oldest being the Late Permian Archaeomalthus synoriacos. It is one of the oldest families of beetles still existing today.
The Trachypachidae 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 and Argentina. They were much more diverse in the past, with dozens of described species from the Mesozoic.
Myxophaga is the second-smallest suborder of the Coleoptera after Archostemata, consisting of roughly 65 species of small to minute beetles in four families. The members of this suborder are aquatic and semiaquatic, and feed on algae.
Catiniidae is a small extinct family of beetles known from the Early Triassic to the Early Cretaceous. The family is usually classified as a member of the suborder Archostemata, but beetles in this family had smooth elytra unlike members of the modern-day families Cupedidae and Ommatidae which have elytra with window punctures.
The Ommatidae are a family of beetles in the suborder Archostemata. The Ommatidae are considered the extant beetle family that has most ancestral characteristics. There are only seven extant species, confined to Australia and South America. However, the geographical distribution was much wider during the Mesozoic spanning across Eurasia and Australia, suggesting that they were widespread on Pangea. So far, over 26 extinct genera containing over 170 species of these beetles have been described. Three extant genera have been assigned to this family: Omma,Tetraphalerus and Beutelius. The family is considered to be a subfamily of Cupedidae by some authors, but have been found to be more closely related to Micromalthidae in molecular phylogenies. A close relationship with Micromalthidae is supported by several morphological characters, including those of the mandibles and male genitalia. Due to their rarity, their ecology is obscure, it is likely that their larvae feed on deadwood.
Brochocoleus is an extinct genus of beetles in the family Ommatidae, known from the Early Jurassic to the Early Late Cretaceous. 9 species are currently recognised, with many species being reassigned to other genera by Kirejtshuk's major systematic revision in 2020.
Zygadenia is an extinct genus of archostematan beetles from the Jurassic to Cretaceous. It is considered to be a senior synonym of Notocupes by Kirejtshuk (2020), but other researchers suggest to reserve the genus Zygadenia as a form taxon for isolated elytra that probably belong to the genus Notocupes, while retaining Notocupes as a valid genus for complete body fossils.
Cionocoleus is an extinct genus of beetles in the family Ommatidae.
Fuscicupes is an extinct genus of beetles from the Early Cretaceous of eastern China. It contains only one species, Fuscicupes parvus, which was described from a single specimen from Tuanwang, Laiyang city in Shandong province, from the Aptian aged Laiyang Formation. Fuscicupes is included in the family Ommatidae by some authors, but was excluded from it by Kirejtshuk (2020) because of the poor preservation of the only known specimen and the lack of characteristics to assign it to a suborder or family of beetles.
Omma is a genus of beetles in the family Ommatidae. Omma is an example of a living fossil. The oldest species known, O. liassicum, lived during the final stage of the Triassic (Rhaetian), over 200 million years ago, though the placement of this species in Omma has been questioned. Numerous other fossil species are known from the Jurassic and Cretaceous of Europe and Asia. The only living species is Omma stanleyi, which is endemic to Australia. Three other extant species endemic to Australia that were formerly part of this genus were moved to the separate genus Beutelius in 2020.Omma stanleyi is strongly associated with wood, being found under Eucalyptus bark and exhibiting thanatosis when disturbed. Its larval stage and many other life details are unknown due to its rarity. Males are typically 14–20 mm in length, while females are 14.4-27.5 mm. Omma stanleyi occurs throughout eastern Australia from Victoria to Central Queensland.
Tetraphalerus is a genus of beetles in the family Ommatidae, It is currently known from two extant species native to South America and several fossil species from the Jurassic and Cretaceous of Asia.
The Protocoleoptera are a paraphyletic group of extinct beetles, containing the earliest and most primitive lineages of beetles. They represented the dominant group of beetles during the Permian, but were largely replaced by modern beetle groups during the following Triassic. Protocoleopterans typically possess prognathous (horizontal) heads, distinctive elytra with regular window punctures, culticles with tubercles or scales, as well as a primitive pattern of ventral sclerites, similar to the modern archostematan families Ommatidae and Cupedidae. They are thought to have been xylophagous and wood boring.
Permocupedidae is a family of Protocoleopteran stem group beetles. They first appeared during the Early Permian, and were one of the dominant groups of beetles during the Middle Permian. They became rare in the Late Permian, with only one species known from the Triassic, Frankencupes ultimus from the Middle Triassic (Anisian) Röt Formation of Germany. They are thought to have been xylophagous, which is presumed to be the ancestral ecology of beetles.
Allophalerus is an extinct genus of beetle in the family Ommatidae. It is known from nine species formerly included in the genus Tetraphalerus.
Bukhkalius is an extinct genus of beetle belonging to the family Ommatidae, it contains the single species, Bukhkalius lindae. It was described in 2017 initially as a species of the extant genus Tetraphalerus and was placed into a separate monotypic genus in 2020, which was reaffirmed in a 2021 study. It is known from a single specimen from Burmese amber, dating to the Cenomanian stage of the Late Cretaceous. The specimen is around 4.7 mm long and around 1.3 mm wide.
Clessidromma is an extinct genus of ommatid beetle. It currently contains a single species Clessidromma palmeri, known from the Cenomanian aged Burmese amber of Myanmar. Kirejtshuk (2020) synonymised Lepidomma with Clessidromma and included two additional species in the latter: C. tianae, originally the type species of Lepidomma, and C. zengi, a newly described species. Li et al. (2021) disputed the synonymy of Lepidomma with Clessidromma, maintaining Lepidomma as a separate genus, and transferred C. zengi to a new genus, Kirejtomma, in 2021.
Diluticupes is an extinct genus of beetle in the family Ommatidae.
Liassocupes is an extinct genus of ommatid beetle from the Jurassic period of England. The only included species is Liassocupes parvus. It is known from compression fossils found at Flatstones near Charmouth in the Sinemurian aged part of the Charmouth Mudstone Formation, Dorset. Other species previously assigned to the genus include Liassocupes (?) maculatus described by Whalley in 1985 from the same locality, but this was subsequently suggested by Ponomarenko to belong to either Omma or Tetraphalerus and was considered to belong to the genus Brochocoleus by Kirejtshuk (2020). Another species Liassocupes (?) giganteus also described by Whalley (1985) from the same locality, was found to be a member of the genus Mimemala in the extinct family Schizocoleidae.
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.
Notocupes is an extinct genus of medium-sized archostematan beetles from the Mesozoic Era of Eurasia, including over 50 described species. Historically, the genus was classified as a member of the family Ommatidae, but the presence of characters such as the horizontal mandibular cutting edge, separated procoxae and overlapping abdominal sternites indicate that the genus may have a closer affinity with the family Cupedidae. Notocupes is considered to be a junior synonym of Zygadenia by Kirejtshuk (2020), but other researchers suggest to reserve the genus Zygadenia as a form taxon for isolated elytra that probably belong to the genus Notocupes, while retaining Notocupes as a valid genus for complete body fossils. Most species of Notocupes were described from compression fossils. An additional three species were described from Cenomanian-aged Burmese amber, which were treated as a separate genus, Echinocups, by Kirejtshuk (2020), but Li et al. (2023) consider Echinocups to be a junior synonym of Notocupes. Notocupes has a flattened body, which may suggest that it occupied narrow habitats, such as living under bark. Some species had serrated/spined margins of the carapace, which may have served as a defense against predators, or served as camouflage to resemble bark.
