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.
Thermonectus is a genus of beetle in family Dytiscidae. This genus is native to the New World, and mainly from warm temperate to tropical in distribution, but one species, T. basillaris occurs as far north as southern Ontario, Canada. They inhabit a wide range of freshwater habitats with static water and are often common. They are generally about 0.8–1.5 cm (0.3–0.6 in) long and a few species from desert pools in North America have a distinct yellow-spotted pattern on a black background.
Coptotomus is a genus of predaceous diving beetles in the family Dytiscidae, the only genus of the subfamily Coptotominae. There are about six described species in Coptotomus, found in North America and the Neotropics.
Copelatus chevrolati is a species of diving beetle. It is part of the genus Copelatus in the subfamily Copelatinae of the family Dytiscidae. It was described by Aubé in 1838. There are two described subspecies: C. c. chevrolati and C. c. renovatus.
Copelatus glyphicus is a species of diving beetle. It is part of the genus Copelatus in the subfamily Copelatinae of the family Dytiscidae. It was described by Say in 1823.
Thermonectus nigrofasciatus is a species of diving beetle native to the eastern United States. T. nigrofasciatus is distinguished by its black, postmedian transverse blotch on its elytra, hence "nigrofasciatus."
Thermonectus sibleyi is a species of diving beetle native to western Mexico and southern Arizona, United States. T. sibleyi reaches a total length of 11.4 to 13.8 millimetres and has an overall light, speckled color pattern.
Hydroporini is a tribe of predaceous diving beetles in the family Dytiscidae. There are at least 730 described species in Hydroporini.
Hydroporinae is a subfamily of predaceous diving beetles in the family Dytiscidae. There are at least 2,200 described species in Hydroporinae.
Dytiscinae is a subfamily of predaceous diving beetles in the family Dytiscidae. There are at least 20 genera and 380 described species in Dytiscinae.
Cybistrinae is a subfamily of predaceous diving beetles in the family Dytiscidae. There are about 7 genera and more than 140 described species in Cybistrinae.
Hydrodytinae is a subfamily of predaceous diving beetles in the family Dytiscidae. There are at least two genera and four described species in Hydrodytinae.
Liadytiscinae is a subfamily of extinct predaceous diving beetles in the family Dytiscidae. There are about 5 genera and 10 described species in Liadytiscinae.
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.
Brancuporus is a genus of predaceous diving beetles in the family Dytiscidae. There are at least two described species in Brancuporus. They are found in Australasia.
Ereboporus is a genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Ereboporus, E. naturaconservatus, found in North America.
Etruscodytes is a genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Etruscodytes, E. nethuns, found in the Palearctic.
Fontidessus is a genus of predaceous diving beetles in the family Dytiscidae. There are about seven described species in Fontidessus. They are found in the Neotropics.
Neobidessodes is a genus of predaceous diving beetles in the family Dytiscidae. There are about 10 described species in Neobidessodes. They are found in Australasia. The genus was first described in 2009, and the type species is N. denticulatus.
Psychopomporus is a genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Psychopomporus, P. felipi, found in North America.
