The cranial endocast of the Upper Devonian dipnoan Chirodipterus australis

Abstract

One of the first endocasts of a dipnoan (lungfish) to be realised was that of the Upper Devonian taxon Chirodipterus australis. This early interpretation was based on observations of the shape of the cranial cavity alone and was not based on a natural cast or 'steinkern' nor from serial sectioning. The validity of this reconstruction is therefore Middle Devonian dipnoan taxa. Notably, the sJall utricular recess is unexpected for a taxon of this age, whereas the ventral expansion of the telencephalon is Jore typical of Jore derived taxa.The presence of such 'priJitive' characters in C. australis supports its relatively basal position as deJonstrated in the Jost recent phylogenies of Devonian Dipnoi.