Beetles are insects that form the order Coleoptera, in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 described species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal species; new species are discovered frequently, with estimates suggesting that there are between 0.9 and 2.1 million total species. Found in almost every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are serious agricultural pests, such as the Colorado potato beetle, while others such as Coccinellidae eat aphids, scale insects, thrips, and other plant-sucking insects that damage crops.
Spercheus is a genus of aquatic beetles which are placed in a family of their own, Spercheidae within the Hydrophiloidea. About 20 species are known from around the world except the Nearctic with the majority being from the Oriental and Afrotropical Realms.
Weevils are beetles belonging to the superfamily Curculionoidea, known for their elongated snouts. They are usually small – less than 6 mm in length – and herbivorous. Approximately 97,000 species of weevils are known. They belong to several families, with most of them in the family Curculionidae. It also includes bark beetles, which while morphologically dissimilar to other weevils in lacking the distinctive snout, is a subfamily of Curculionidae. Some other beetles, although not closely related, bear the name "weevil", such as the biscuit weevil, which belongs to the family Ptinidae.
The telephone-pole beetle is a beetle native to the eastern United States, and the only living representative of the otherwise extinct family Micromalthidae. They have an unusual life cycle involving asexually reproducing (parthenogenetic) female larvae, as well as non-functional "ghost adults".
The Adephaga are a suborder of beetles, and with more than 40,000 recorded species in 10 families, the second-largest of the four beetle suborders. Members of this suborder are collectively known as adephagans. The largest family is Carabidae which comprises most of the suborder with over 40,000 species. Adephaga also includes a variety of aquatic beetles, such as predaceous diving beetles and whirligig beetles.
The Archostemata are the smallest suborder of beetles, consisting 45 living species in five families. 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. Genetic research suggests that modern archostematans are a monophyletic group. Some genetic studies have recovered archostematans as the sister group of Myxophaga.
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.
The Peloridiidae or moss bugs are a family of true bugs, comprising eighteen genera and thirty-four species. They are small, ranging in length from 2 to 4 mm, rarely seen, peculiarly lumpy, flattened bugs found in Patagonia, New Zealand, eastern Australia, Lord Howe Island, and New Caledonia. Peloridiids are found amongst mosses and liverworts, commonly in association with southern beech forests. They have become known as moss bugs for their habit of feeding on mosses. Almost all Peloridiidae species are flightless, except one. Their present distribution suggests they have existed since before the breakup of Gondwana. They are the only living members of the suborder Coleorrhyncha, which first appeared in the Upper Permian, over 250 million years ago.
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.
The Stephanidae, sometimes called crown wasps, are a family of parasitoid wasps. They are the only living members of the superfamily Stephanoidea. Stephanidae has at least 345 living species in 11 genera. The family is considered cosmopolitan in distribution, with the highest species concentrations in subtropical and moderate climate zones. Stephanidae also contain four extinct genera described from both compression fossils and inclusions in amber.
Cleridae are a family of beetles of the superfamily Cleroidea. They are commonly known as checkered beetles. The family Cleridae has a worldwide distribution, and a variety of habitats and feeding preferences.
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 may suggest that it was apterous.
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.
Ascioplaga is a genus of beetles in the family Cupedidae, containing two species endemic to New Caledonia and one described from northern Queensland in Australia. The Australian species, Ascioplaga scalena, was originally described as a species of Adinolepis, and was transferred to Ascioplaga in 2009.
Priacma is a genus of beetles in the family Cupedidae. It contains a single extant species, Priacma serrata native to western North America and one fossil species, P. megapuncta from the Cenomanian aged Burmese amber. Species previously assigned to the genus from the Yixian Formation of China have been subsequently placed in the separate genus Apriacma.
Rhipsideigma is a genus of beetles in the family Cupedidae. It contains five species, four of which are endemic to Madagascar, the other being endemic to the northern coast of Tanzania. They vary in length from 13 mm to 20 mm, and are up to 6 mm wide.
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.
Aspidytidae is a family of aquatic beetles of the suborder Adephaga, described in 2002 from specimens in South Africa and China. There are only two known species in the family and these were originally described in the genus Aspidytes, but later the new genus Sinaspidytes was erected for the species found in China. The family can also be referred to by its trivial name cliff water beetles.
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.
Coleopsis archaica is an extinct species of stem-group beetle. It is the only member of the genus Coleopsis and family Coleopsidae. It is known from a single specimen from the Early Permian (Asselian) of western Germany, estimated to be about 297 million years old. It is currently the oldest known beetle.
