Reproduction in Middle Triassic actinopterygians; complex fin structures and evidence of viviparity in fossil fishes

Abstract

New well-preserved specimens of Peltopleurus lissocephalus Brough, 1939, a small actinopterygian fish of the Alpine Middle Triassic, are described. Some of them show a highly modified anal fin, with a brush-shaped holdfast device and a gonopodium-like structure, possibly used during mating behaviour. Additional examples of modified anal fins are reported for the genera Cephaloxenus and Habroichthys. Evidence for viviparity within the genus Saurichthys, found at the same localities, is discussed and compared with earlier reports of the phenomenon. A comparison is made of the different reproductive strategies used in some Middle Triassic actinopterygian fishes.