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.
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.
The Dytiscidae – based on the Greek dytikos (δυτικός), "able to dive" – are the predaceous diving beetles, a family of water beetles. They occur in virtually any freshwater habitat around the world, but a few species live among leaf litter. The adults of most are between 1 and 2.5 cm (0.4–1.0 in) long, though much variation is seen between species. The European Dytiscus latissimus and Brazilian Megadytes ducalis are the largest, reaching up to 4.5 cm (1.8 in) and 4.75 cm (1.9 in) respectively. In contrast, the smallest is likely the Australian Limbodessus atypicali of subterranean waters, which only is about 0.9 mm (0.035 in) long. Most are dark brown, blackish, or dark olive in color with golden highlights in some subfamilies. The larvae are commonly known as water tigers due to their voracious appetite. They have short, but sharp mandibles and immediately upon biting, they deliver digestive enzymes into prey to suck their liquefied remains. The family includes more than 4,000 described species in numerous genera.
Weald Clay or the Weald Clay Formation is a Lower Cretaceous sedimentary rock unit underlying areas of South East England, between the North and South Downs, in an area called the Weald Basin. It is the uppermost unit of the Wealden Group of rocks within the Weald Basin, and the upper portion of the unit is equivalent in age to the exposed portion of the Wessex Formation on the Isle of Wight. It predominantly consists of thinly bedded mudstone. The un-weathered form is blue/grey, and the yellow/orange is the weathered form, it is used in brickmaking.
Hydrophiloidea, known as water scavenger beetles, is a superfamily of beetles. Until recently it included only a single family, the Hydrophilidae, but several of the subfamilies have been removed and raised to family rank. Hydrophiliidae remains by far the largest member of the group, with nearly 3,000 described species. The other families have no more than 400 species. The Histeroidea are closely related and sometimes considered part of a sensu lato Hydrophiloidea. The majority of the clade is aquatic, which is thought to be the ancestral ecology of the group, with some lineages like Sphaeridiinae becoming secondarily terrestrial. Modern representatives of the group first appeared during the Late Jurassic.
Coptoclavidae is an extinct family of aquatic beetles in the suborder Adephaga. The Coptoclavidae lived from the Late Triassic to the Early Cretaceous. Coptoclavidae is a member of the adephagan clade Dytiscoidea, which contains other aquatic beetles. Suggested reasons for their extinction to include the rise of teleost fish, or competition with Gyrinidae and Dytiscidae, which possess defensive secretions and sucking channels in the mandibles of larvae, which coptoclavids likely lacked. It has been suggested that the genus Timarchopsis and the subfamily Timarchopsinae are only distantly related to other coptoclavids based on cladistic analysis, with Timarchopsis being more closely related to geadephagans like carabids and trachypachids instead. Another study also suggested similarly for Coptoclavisca and possibly other coptoclaviscines.
Protorabinae is an extinct subfamily of beetles in the family Carabidae. It contains 36 species in 13 genera, all extinct.
Cretodytes is an extinct genus of beetles in the family Dytiscidae, containing the following species:
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.
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.
Mesoraphidiidae is an extinct family of snakeflies in the suborder Raphidiomorpha. The family lived from the Late Jurassic through the Late Cretaceous and is known from twenty-five genera. Mesoraphidiids have been found as both compression fossils and as inclusions in amber. The family was first proposed in 1925 by the Russian paleoentomologist Andrey Vasilyevich Martynov based on Upper Jurassic fossils recovered in Kazakhstan. The family was expanded in 2002 by the synonymizing of several other proposed snakefly families. The family was divided into three subfamilies and one tribe in a 2011 paper, further clarifying the relationships of the included genera.
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.
Liadytiscinae is a subfamily of extinct predaceous diving beetles in the family Dytiscidae. There are about 5 genera and 10 described species in Liadytiscinae. All currently known members of the subfamily are known from the Early Cretaceous Jehol Biota of China.
Liadroporus is an extinct genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Liadroporus, L. elegans.
Liadytiscus is an extinct genus of predaceous diving beetles in the family Dytiscidae. There are at least three described species in Liadytiscus.
Mesoderus is an extinct genus of predaceous diving beetles in the family Dytiscidae. There are at least four described species in Mesoderus.
Liadyxianus is an extinct genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Liadyxianus, L. kirejtshuki.
Mesodytes is an extinct genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Mesodytes, M. rhantoides.
Elcanidae are an extinct family of Mesozoic and early Cenozoic orthopterans. Members of the family are distinguished by the presence of spurs on the distal part of the metatibia, unique among orthopterans, these have been suggested to have been used for controlling gliding, swimming aids, or for jumping on water. The group combines characteristics from both major groups of orthopterans, with long antennae and nymphal morphology similar to Ensifera, but with wing venation and adult morphology more similar to Caelifera. Elcanidae is part of Elcanoidea, which is thought to have diverged from living orthopterans by the beginning of the Permian, around 300 million years ago. The family also includes Permelcanidae, known from the Early-Late Permian. The relationship of Elcanoidea to Ensifera and Caelifera is currently unresolved. Elcanids are known from the Late Triassic to Paleocene of Eurasia, North and South America. Some members of the group exhibited aposematic coloration.
