The Cupedidae are a small family of beetles, notable for the square pattern of "windows" on their elytra, which give the family their common name of reticulated beetles.
The whirligig beetles are water beetles, comprising the family Gyrinidae that usually swim on the surface of the water if undisturbed, though they swim underwater when threatened. They get their common name from their habit of swimming rapidly in circles when alarmed, and are also notable for their divided eyes which are believed to enable them to see both above and below water. The family includes some 700 extant species worldwide, in 15 genera, plus a few fossil species. Most species are very similar in general appearance, though they vary in size from perhaps 3 mm to 18 mm in length. They tend to be flattened and rounded in cross section, in plain view as seen from above, and in longitudinal section. In fact their shape is a good first approximation to an ellipsoid, with legs and other appendages fitting closely into a streamlined surface. Whirligig beetles belong to the beetle suborder Adephaga, which also includes ground beetles and diving beetles.
Eucinetidae is a family of beetles, notable for their large coxal plates that cover much of the first ventrite of the abdomen, sometimes called plate-thigh beetles. The family is small for beetles, with about 50 species in 11 genera, but are found worldwide.
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.
Byrrhoidea is a superfamily of beetles belonging to Elateriformia that includes several families which are either aquatic or associated with a semi-aquatic habitat. Other than the superfamily Hydrophiloidea, most of the remaining Polyphagan beetles which are aquatic are in this superfamily.
The Cerophytidae are a family of beetles belonging to Elateroidea. Larvae are associated with rotting wood, on which they are presumed to feed. The family contains over 20 species in five genera, primarily distributed in the New World, but also in Eurasia and Africa. 17 fossil species in 7 genera are known extending to the Early Jurassic. Like some other elateroids, the adults are capable of clicking.
The family Oedemeridae is a cosmopolitan group of beetles commonly known as false blister beetles, though some recent authors have coined the name pollen-feeding beetles. There are some 100 genera and 1,500 species in the family, mostly associated with rotting wood as larvae, though adults are quite common on flowers. The family was erected by Pierre André Latreille in 1810.
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.
Boganiidae is a family of beetles, in the superfamily Cucujoidea. Members of the family are found in southern Africa, Australia and New Caledonia. Adults and larvae are pollenivorous, feeding on the pollen of cycads and flowering plants of the families Myrtaceae, Meliaceae, Cunoniaceae and Elaeocarpaceae. Metacucujus and Paracucujus act as pollinators for cycads Encephalartos and Macrozamia respectively. This association with cycads goes back to at least the Mid-Cretaceous, with an extinct form being found with preserved cycad pollen in 99 million year old Burmese amber.
Sphindidae is a family of beetles, in the suborder Polyphaga. They are called slime mold beetles due to their exclusive feeding on slime molds during adult and larval stages, other aspects of their life history are obscure. Palaeontological discoveries since 2015 have added to the geologic history of Sphindidae, including the discovery of Libanopsis, placed in the extinct subfamily Libanopsinae.
Helotidae is a family of beetles, in the suborder Polyphaga. The family includes about five extant genera, Helota MacLeay, Neohelota Ohta, Afrohelotina Kirejtshuk, Metahelotella Kirejtshuk, and Strophohelota Kirejtshuk. Helotidae are found mainly in the Old World tropics and are absent from Australia and Madagascar. The antennae are clubbed on the final three segments and is retractable within grooves under the head. The wings have reduced venation with just 4 anal veins. Helotids are known to be associated with sap, fruit and flowers, and the larvae of some species are known to bore into wood in order to pupate.
The Brachypsectridae are a family of beetles commonly known as the Texas beetles. There are only two extant genera, Brachypsectra and Asiopsectra. Brachypsectra has a cosmopolitan distribution, mostly in arid regions, while Asiopsectra is found in Central Asia and the Middle East.
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.
Monotomidae is a family of beetles in the superfamily Cucujoidea. The family is found worldwide, with approximately 240 species in 33 genera. The ecological habits of the family are diverse, with different members of the group being found under tree bark, in decaying vegetation, on flowers and in ant nests. Their ecology is obscure, while at least some species are mycophagous, feeding on the fruiting bodies of ascomycete fungi, Rhyzophagus are predators on bark beetles and possibly Phoridae larvae, with the larvae of some species also being mycophagous.
Eucnemidae, or false click beetles, are a family of elateroid beetles including about 1700 species distributed worldwide.
Chelonariidae or turtle beetles is a family of beetles in the superfamily Byrrhoidea. It was described by Blanchard in 1845. There are 3 genera with around 300 described species. Little is known of their ecology, though it seems they are associated with the roots of orchids and the nests of ants and termites. Their exoskeletons are heavily sclerotised and their limbs can be effectively retracted into their bodies due to the presence of socket-like cavities. Adult specimens have seed-shaped bodies that are typically colored brown or black with lighter patches.
Elmidae, commonly known as riffle beetles, is a family of beetles in the superfamily Byrrhoidea described by John Curtis in 1830. Both adults and larvae are usually aquatic, living under rocks in fast-flowing shallow areas of streams, such as riffles, feeding on algae and biofilms. There are more than 150 genera and 1,500 described species in Elmidae. The oldest record of the group is Cretohypsilara from the Cenomanian aged Burmese amber.
Clambidae is a family of beetles. They are known commonly as the minute beetles or the fringe-winged beetles. They are found worldwide on every continent except Antarctica.
Dascillidae is a family of beetles within the clade Elateriformia. There are about 100 extant species in 11 genera, which are found worldwide. Dascillidae together with Rhipiceridae form the super family Dascilloidea.
Artematopodidae is a family of soft-bodied plant beetles in the superfamily Elateroidea. They are mostly found in understory forest foliage. The life history of the group is obscure, larvae of the genera Eurypogon and Macropogon likely feed on moss, while the larvae of Artematopus have been fed insect remains. The oldest fossils of the family date to the Middle Jurassic.
