Cybister
Introduction ''Cybister lateralimarginalis''Comparison of ''Cybister'' and ''Dytiscus'' larvae'''''Cybister''''' ('kybistētēr' = diver, tumbler), is a genus of beetle in family Dytiscidae. They are found in much of the world, including all continents except Antarctica. As of 2021 there are 96 species and 9 additional subspecies among four subgenera in the genus.
Description Adult ''Cybister'' have broad hind legs with unequal tarsal claws (the inner claw being smaller and sometimes absent) and a fringe on the outer margin of the tarsus. They range in length from 13 mm (''C. parvus'' from Brazil) to 43 mm (''C. bimaculatus'' from the Afrotropics). Adult males of the North American species have several ridges on the coxae of the hind legs, forming a stridulatory device.Larvae have a frontal tooth on the head and lack cerci. North American species can grow up to 80 mm long.
Ecology ''Cybister'' live in lentic (still fresh water) habitats that have vegetation.Like other diving beetles, ''Cybister'' are predatory. Larvae of ''C. japonicus'' prey on insects (mainly Odonata nymphs and the backswimmer ''Notonecta triguttata'') in their first two instars, while third-instar larvae prey on vertebrates (tadpoles and fish). Larvae of ''C. rugosus'' feed on both invertebrates and vertebrates in all instars.
Importance ''Cybister chinensis'' (sometimes misidentified as ''C. japonicus'') is used in a game in Korea. The water beetle game (''mul bang gae nori'') is played in an oval, water-filled tank with vertical flanges along its inner edge and prizes on the tank rim. The game is played by dropping a ''C. chinensis'' through a funnel into the center of the tank, after which it swims towards the edge of the tank and stops in one of the slots formed by the metal flanges. If a prize is above this slot, the player wins it.The swimming behaviour of ''C. lateralimarginalis'' has inspired (biomimetics) the design of a legged underwater robot.
List of species ===Subgenus ''Cybister'' Curtis, 1827===* ''Cybister alluaudi'' Guignot, 1936* ''Cybister bengalensis'' Aubé, 1838* ''Cybister buqueti'' Aubé, 1838* ''Cybister cardoni'' Severin, 1890* ''Cybister celebensis'' Sharp, 1882* ''Cybister cephalotes'' Sharp, 1882* ''Cybister chinensis'' Motschulsky, 1854* ''Cybister cinctus'' Sharp, 1882* ''Cybister cognatus'' Sharp, 1882* ''Cybister concessor'' Guignot, 1947* ''Cybister confusus'' Sharp, 1882* ''Cybister crassipes'' Sharp, 1882* ''Cybister crassiusculus'' Régimbart, 1895* ''Cybister dejeanii'' Aubé, 1838* ''Cybister dytiscoides'' Sharp, 1882* ''Cybister ellipticus'' LeConte, 1852* ''Cybister explanatus'' LeConte, 1852* ''Cybister extenuans'' (Walker, 1858)* ''Cybister favareli'' Guignot, 1936* ''Cybister fimbriolatus'' (Say, 1823)* ''Cybister fumatus'' Sharp, 1882* ''Cybister godeffroyi'' (Wehncke, 1876)* ''Cybister gracilis'' Sharp, 1882* ''Cybister gschwendtneri'' Guignot, 1935* ''Cybister guerini'' Aubé, 1838* ''Cybister guignoti'' Gschwendtner, 1936** ''Cybister guignoti pseudosenegalensis'' Guignot, 1936* ''Cybister hypomelas'' Régimbart, 1892* ''Cybister janczyki'' Mouchamps, 1957* ''Cybister javanus'' Aubé, 1838* ''Cybister laevis'' Falkenström, 1936* ''Cybister lateralimarginalis'' (De Geer, 1774)** ''Cybister lateralimarginalis ponticus'' Sharp, 1882** ''Cybister lateralimarginalis torquatus'' (Fischer von Waldheim, 1829)* ''Cybister lewisianus'' Sharp, 1873* ''Cybister limbatus'' (Fabricius, 1775)* ''Cybister loxidiscus'' Wilke, 1920* ''Cybister natalensis'' (Wehncke, 1876)* ''Cybister nebulosus'' Gschwendtner, 1931* ''Cybister occidentalis'' Aubé, 1838* ''Cybister pectoralis'' Sharp, 1882* ''Cybister pederzanii'' Rocchi, 1979* ''Cybister reichei'' Aubé, 1838* ''Cybister rugosus'' (W.S.Macleay, 1825)* ''Cybister rugulosus'' (Redtenbacher, 1844)* ''Cybister schoutedeni'' Gschwendtner, 1932* ''Cybister semiaciculatus'' Schaufuss, 1887* ''Cybister senegalensis'' Aubé, 1838* ''Cybister straeleni'' Guignot, 1952* ''Cybister tibialis'' Sharp, 1882* ''Cybister tripunctatus'' (Olivier, 1795)** ''Cybister tripunctatus africanus'' Laporte, 1835** ''Cybister tripunctatus lateralis'' (Fabricius, 1798)** ''Cybister tripunctatus temnenkii'' Aubé, 1838* ''Cybister ventralis'' Sharp, 1882* ''Cybister weckwerthi'' Hendrich, 1997* ''Cybister wittmeri'' Brancucci, 1979* ''Cybister yulensis'' Guignot, 1956===Subgenus ''Megadytoides'' Brinck, 1945===* ''Cybister marginicollis'' Boheman, 1848===Subgenus ''Melanectes'' Brinck, 1945===* ''Cybister alemon'' Guignot, 1948* ''Cybister aterrimus'' Régimbart, 1899* ''Cybister basilewskyi'' Guignot, 1950* ''Cybister bellicosus'' Guignot, 1947* ''Cybister bimaculatus'' Aubé, 1838* ''Cybister blotei'' Guignot, 1936* ''Cybister brevis'' Aubé, 1838* ''Cybister burgeoni'' Guignot, 1947* ''Cybister convexus'' Sharp, 1882* ''Cybister dehaanii'' Aubé, 1838* ''Cybister desjardinsii'' Aubé, 1838* ''Cybister dissentiens'' Mouchamps, 1957* ''Cybister distinctus'' Régimbart, 1878* ''Cybister ertli'' Zimmermann, 1917* ''Cybister feraudi'' Guignot, 1934* ''Cybister griphodes'' Guignot, 1942* ''Cybister immarginatus'' Fabricius, 1798) * ''Cybister insignis'' Sharp, 1882** ''Cybister insignis caprai'' Guignot, 1949** ''Cybister insignis purpureovirgatus'' Guignot, 1946* ''Cybister irritans'' (Dohrn, 1875)* ''Cybister longulus'' Gschwendtner, 1932* ''Cybister lynceus'' J.Balfour-Browne, 1950* ''Cybister mesomelas'' Guignot, 1942* ''Cybister mocquerysi'' Régimbart, 1895* ''Cybister modestus'' Sharp, 1882* ''Cybister nigrescens'' Gschwendtner, 1933* ''Cybister nigripes'' Wehncke, 1876* ''Cybister operosus'' Sharp, 1882* ''Cybister owas'' Laporte, 1835* ''Cybister papuanus'' Guignot, 1956* ''Cybister pinguis'' Régimbart, 1895* ''Cybister posticus'' Aubé, 1838* ''Cybister procax'' Guignot, 1947**''Cybister procax vicinatus'' Mouchamps, 1957* ''Cybister prolixus'' Sharp, 1882* ''Cybister semirugosus'' Harold, 1878* ''Cybister siamensis'' Sharp, 1882* ''Cybister smaragdinus'' Régimbart, 1895* ''Cybister sugillatus'' Erichson, 1834* ''Cybister sumatrensis'' Régimbart, 1883* ''Cybister thermolytes'' Guignot, 1947* ''Cybister vicinus'' Zimmermann, 1917* ''Cybister vulneratus'' Klug, 1834* ''Cybister zimmermanni'' Mouchamps, 1957===Subgenus ''Neocybister'' K.B. Miller, Bergsten & Whiting, 2007===* ''Cybister festae'' Griffini, 1895* ''Cybister puncticollis'' (Brullé, 1837)===Subgenus unknown===* ''Cybister parvus'' Trémouilles, 1984===Fossil species===These seven extinct species are known only from fossils:* †''Cybister agassizi'' Heer, 1862* †''Cybister atavus'' Heer, 1862* †''Cybister fractus'' Riha, 1974* †''Cybister imperfectus'' Riha, 1974* †''Cybister mancus'' Riha, 1974* †''Cybister nicoleti'' Heer, 1862* †''Cybister rotundatus'' Riha, 1974
References
External links * ''Cybister'' on Fauna Europaea* ''Cybister'' on BugGuide.Net*  Synopsis of the described coleoptera of the world**