A new rhizodontiform fish from the Early Carboniferous of Victoria, Australia, with remarks on the phylogenetic position of the group

Abstract

ABSTRACT Barameda decipiens, gen. nov. (Woodward, 1906) is described from the Early Carboniferous Mansfield Group, Victoria, Australia. It differs from other rhizodontiforms (Strepsodus, Rhizodus, Screbinodus, Sauripterus) by the shape of the skull roofing bones, course of the supratemporal sensory line, vertebral structure, and pectoral fin skeleton. The skull roof of Barameda, gen. nov., differs from that of Osteolepiformes in having a larger extratemporal bone that contacts the intertemporal, by the overlap areas on the intertemporal, and in having fewer snout bones. The cheek has a very large postorbital bone, and the lacrimai is narrow. There are two external nostrils, which are situated close together and differ in their position in the only other rhizodontiform for which they are known, suggesting that the group was not choanate. Rhizodontiforms are a monophyletic group characterized by specializations of the pectoral girdle and fin. They may be placed in Schultze's (1987) scheme of osteichthyan in...