Archostemata Temporal range: | |
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Tenomerga mucida | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Coleoptera |
Suborder: | Archostemata Kolbe, 1908 |
Families | |
Crowsoniellidae Contents |
The Archostemata are the smallest suborder of beetles, consisting of 50 living species in five families and over 200 described fossil species. [1] They are an ancient lineage with a number of primitive characteristics. Antennae may be thread-shaped (filiform) or like a string of beads (moniliform). This suborder also contains the only beetles where both sexes are paedogenic, Micromalthus debilis . Modern archostematan beetles are considered rare, but were more diverse during the Mesozoic.
The term "Archostemata" is used more broadly by some authors to include both modern archostematans as well as stem-group beetles like "protocoleopterans", which some modern archostematans closely resemble to due to their plesiomorphic morphology. [2] Genetic research suggests that modern archostematans are a monophyletic group. Some genetic studies have recovered archostematans as the sister group of Myxophaga. [3]
A 2009 paper argued that the poor diversity of modern Archostemata, compared with the staggering evolutionary success of most other Coleoptera lineages, could be due to the lower efficiency of the thoracic locomotor apparatus, the absence of cryptonephric Malpighian tubules, and competition with other beetles more adapted to angiosperms. [4]
There are five extant families. [5] [6]
A partial phylogeny of Archostemata and early coleopterans, based on palaeontological data, from Boudinot et al. 2022. [2]
Coleoptera |
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According to Li et al. 2023; [1] archostematan families are in bold.
Coleoptera | ||||||||||||||||
The telephone-pole beetle is a beetle native to the eastern United States and the only living representative of the otherwise extinct family Micromalthidae. Larvae of the beetle live in decaying wood and can be pests to wooden structures, lending them their common name, the 'telephone-pole beetle.'
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.
Jurodidae is a family of beetles that was originally described for the extinct genus Jurodes, known from the Middle-Late Jurassic of Asia. In 1996, a living species, Sikhotealinia zhiltzovae was discovered in the Sikhote-Alin mountains in southeastern Siberia, and assigned to this family. Their placement is uncertain, but are usually considered archostematans. In one study, Sikhotealinia and Jurodes were considered a sister group to all other archostematan beetles. However, other authors have considered their placement within beetles as a whole uncertain, due to their mix characteristics of typical Archostemata, as well as Polyphaga and Adephaga.
Blapsium is an extinct genus of beetles from the Middle Jurassic of England. The only described species is B. egertoni, which is known from a single specimen found by the Earl of Enniskillen at the Taynton Limestone Formation, also known as the Stonesfield Slate. The specimen is deposited in the Natural History Museum, London. It is incompletely preserved, lacking a head, pronotum and legs. It has a broad, convex body. It has a very short metathorax, which suggests that it was possibly apterous.
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.
Adinolepis is a genus of beetles in the family Cupedidae containing four species, all endemic to Australia. A fifth species, Adinolepis scalena, was transferred to Ascioplaga in 2009.
Colymbothetidae is an extinct family of beetles in the suborder Adephaga. Colymbothethis is known from larvae from the Upper Triassic of Kazakhstan. They probably belong to the Dytiscoidea.
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.
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.
Magnocoleus is an extinct genus of beetles from the Early Cretaceous of China, between 130.0 and 125.45 Mya. The genus contains a single species, Magnocoleus huangjiapuensis, and is the only member of the family Magnocoleidae in the suborder Archostemata. Magnocoleus was first described by Chinese palaeoentomologist Hong Youchong in 1998, based on fossils of isolated elytra from the Qingshila Formation in Huangjiapu, near the Nantianmen village of Zhangjiakou in Hebei. Recent phylogenetic analyses have suggested that Magnocoleus is closely related to or placed within either Cupedidae or Ommatidae.
Psammodiini is a tribe of aphodiine dung beetles in the family Scarabaeidae. There are more than 30 genera and 470 described species in Psammodiini.
Cybistrini is a tribe of predaceous diving beetles in the family Dytiscidae. There are 7 genera and 128 described extant species in Cybistrini. The same set is also called Cybistrinae by authors viewing it as a subfamily of Dytiscidae.
Myrabolia is the only genus in the beetle family Myraboliidae in the superfamily Cucujoidea. It has about 13 species, found in Australia. Adults and possibly larvae live under the bark of Eucalyptus trees.
Liadytidae is an extinct family of adephagan beetles. There are at least two genera and about seven described species in Liadytidae. They are known from the Early Jurassic to Early Cretaceous of Asia. They are members of the clade Dytiscoidea, and like other members of that group were adapted for aquatic life.
Corythoderini is a tribe of scarab beetles in the family Scarabaeidae. There are about 6 genera and more than 30 described species in Corythoderini.
Odontolochini is a tribe of scarab beetles in the family Scarabaeidae. There are about 6 genera and more than 20 described species in Odontolochini, found in the Neotropics, Australia, and Africa.
Rhyparini is a tribe of scarab beetles in the family Scarabaeidae. There are about 14 genera and more than 120 described species in Rhyparini.
Termitoderini is a tribe of scarab beetles in the family Scarabaeidae. There are at least two genera and about six described species in Termitoderini. They are found in tropical Africa.
Aulonocneminae is a subfamily of scarab beetles in the family Scarabaeidae. There are about 5 genera and more than 50 described species in Aulonocneminae, found in Madagascar and east Asia.