An almost complete but predominantly disarticulated ptyctodont fish, Kimbryanodus williamburyensis n. gen., n.sp. from the Late Devonian Gneudna Formation, is described. The fossils occur as three-dimensionally preserved isolated plates, and this has allowed the reconstruction of the fish. A taxonomic revision of the ptyctodonts was undertaken based on recently described Australian taxa and new reconstructions of Australian, American and European specimens. The phylogenetic analysis supports a threefold division of the ptyctodonts, with Rhamphodopsis being the most basal taxon and the other ptyctodonts divided into those possessing a median dorsal spine, spinal plate and simple V-shaped overlap of the anterior lateral and anterior dorsolateral plates and those taxa which do not.