Cybister

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
Dytiscidae genera
Dytiscidae