New Information on Culmacanthus (Acanthodii: Diplacanthiformes) from the ?Early–Middle Devonian of Southeastern Australia

Abstract

A new articulated acanthodian from the Devonian Bunga Beds on the south coast of New South Wales is assigned to Culmacanthus sp., and reveals that this diplacanthiform has smooth dental plates on the occlusal surfaces of the lower jaws. Within the Acanthodii, this type of element was first identified in “Gladiobranchus” probaton from the earliest Devonian MOTH locality, Northwest Territories, Canada, and has now also been identified in “Euthacanthus” curtus (Lochkovian, Lower Old Red Sandstone, Scotland) and Diplacanthus spp. (Givetian, Scotland and Frasnian, Canada). The dental plates in Culmacanthus have the same morphology as those of “Gladiobranchus” probaton and “Euthacanthus” curtus. Reexamination of type specimens of Culmacanthus shows that its pectoral fin spines do not have long insertions, and the purported lack of prepectoral, admedian and prepelvic fin spines could be due to loss of the elements before burial rather than morphological absence.