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Ranidae (‘true’ frogs; class Amphibia, order Anura) A diverse family of amphibians in which the skeleton is modified for jumping. The tongue always has a notched end. Males often develop vocal sacs. Dendrobates (arrow-poison frogs) of tropical S. America are notable for their extremely vivid warning colours and highly poisonous skin, which secretes batrachotoxin. Rana catesbiana (bullfrog) of N. and Central America, an essentially aquatic species that feeds on other frogs, young alligators, snakes, birds, and small mammals, has paired vocal sacs (and consequent loud voice) and the tympanic membrane is larger than the eye. R. pipiens (leopard frog or meadow frog) is greenish brown with rows of black, brown, or green spots, ringed with a lighter colour; it is common in southern Canada, the USA, and much of Central America. R. temporaria (common frog or European frog) is the most widespread European species (but it does not occur in Ireland). R. ridibunda (marsh frog or laughing frog), an essentially aquatic species, is the largest European frog (up to 17 cm long). There are about 300 species, occurring in all continents except Antarctica; Rana is the only genus with a worldwide distribution, and the only genus in N. America.