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 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.
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.
Cretodytes is an extinct genus of beetles in the family Dytiscidae, containing the following species:
Palaeodytes is an extinct genus of beetles in the family Dytiscidae, containing the following species:
Agabinae is a subfamily of predaceous diving beetles in the family Dytiscidae. There are about 11 genera and more than 460 described species in Agabinae.
Colymbetinae is a subfamily of predaceous diving beetles in the family Dytiscidae. There are about 11 genera and at least 130 described species in Colymbetinae.
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 is as a subfamily of Dytiscidae.
Matinae is a subfamily of predaceous diving beetles in the family Dytiscidae. There are at least 3 genera and about 10 described species in Matinae.
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.
Hydrodytinae is a subfamily of predaceous diving beetles in the family Dytiscidae. There are at least two genera and four described species in Hydrodytinae.
Amurodytes is a genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Amurodytes, A. belovi, found in the Palearctic.
Spanglerodessus is a genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Spanglerodessus, S. shorti. They are found in the Neotropics.
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.
