Revision of the Mesozoic freshwater fish clade Archaeomaenidae

Abstract

Archaeomaenidae is a clade of Mesozoic freshwater fishes that includes the Australian species Archaeomaene tenuis, Madariscus robustus and Wadeichthys oxyops, the Antarctic Oreochima ellioti, the Chinese Zaxilepis qinglongensis, and the Mongolian Gurvanichthys mongoliensis. A comprehensive redescription of the genus Archaeomaene demonstrates that Madariscus robustus is a junior synonym of Archaeomaene tenuis, and thus constitutes an ontogenetic body-size series. A detailed revision of W. oxyops and O. ellioti also confirms their phylogenetic placements within Archaeomaenidae. Furthermore, the incompletely documented taxa Z. qinglongensis and G. mongoliensis are recognized as archaeomaenids. Archaeomaenidae therefore comprises a geographically widely distributed radiation of stem teleosts or teleosteomorphs that is closely related to the archetypal Eurasian clade Pholidophoridae.