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 2024 there are 98 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 up 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 poblanus Arce-Pérez, Novelo-Gutiérrez, & Fery, 2021 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 danxiaensis Jiang, Zhao, Mai, Jia & Hendrich, 2023 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