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.
Phycosecidae is a family of beetles in the superfamily Cleroidea., containing the single genus Phycosecis found in Australia, New Caledonia, New Zealand and Vanuatu. The beetles are small, about 1.5–3.5 mm in length. They live in sandy coastal areas, and are saprophagous, feeding on faeces, carrion, and dead arthropods during the daytime.
Gonipterus is a genus of weevils in the family Curculionidae. There are approximately 20 described species in the genus, most of which are native to Australia. They are all plant feeders and many are specific to a single host species. Gonipterus platensis, Gonipterus pulverulentus, and an undescribed species infest a number of species of Eucalyptus and have spread to other parts of the world where these trees have been planted.
Hoperius is a genus of predaceous diving beetles in the family Dytiscidae. This genus has a single species, Hoperius planatus. It is found in the United States east of the Rocky Mountains.
Sandracottus is a genus of beetles in the family Dytiscidae. These aquatic beetles are found in ponds and slow streams from South Asia east to southern Japan, and south to Australia. They are generally about 1–1.5 cm (0.4–0.6 in) long and often have distinctive markings.
Austrodytes is a genus of beetles in the family Dytiscidae found only in northern Australia. It was first described in 1978 by Chris Watts. The genus contains these two species:
Gibbidessus chipi is a species of beetle in the family Dytiscidae, the only species in the genus Gibbidessus.
Limbodessus is a genus of beetles in the family Dytiscidae, first described by Félix Guignot in 1939. It contains the following species:
Exocelina subjecta is a species of diving beetle in the genus Exocelina of the subfamily Copelatinae in the family Dytiscidae, described by David Sharp in 1882.
Copelatus nigropennis 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 Zimmermann in 1927.
Copelatus portior 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 Félix Guignot in 1956.
Copelatini is a tribe of diving beetles in the family Dytiscidae. It is the sole tribe in the subfamily Copelatinae. The largest genus within the tribe is Copelatus, which has about 470 described species found worldwide, but most diverse in tropical South America, Africa and South-East Asia.
Cybistrini is a tribe of predaceous diving beetles in the family Dytiscidae. There are 12 genera and 130 described extant species in Cybistrini. The same set is also called Cybistrinae by authors viewing it as a subfamily of Dytiscidae.
Byrrhus geminatus is a species of pill beetle in the family Byrrhidae. It is found in North America.
Hydrovatus lyratus, is a species of predaceous diving beetle widespread in South Asia, South East Asia and Australian region.
Antiporus willyamsi is a predaceous diving beetle in the family Antiporus, first described in 1997 by Chris H.S. Watts.
Antiporus hollingsworthi is a species of water beetle in the Scirtidae family, first described in 1997 by Chris Watts.
Barretthydrus geminatus is a species of diving beetle in the family, Dytiscidae, first described in 1927 by Arthur Mills Lea.
Barretthydrus tibialis is a species of freshwater diving beetle in the family, Dytiscidae, first described in 1927 by Arthur Mills Lea.
Barretthydrus stepheni is a species of freshwater diving beetle in the family, Dytiscidae, first described in 1978 by Chris H.S.Watts. The species has been found in New South Wales.
