Gorgonichthys is extinct monospecific genus of large arthrodire placoderm. Fossils are found in the Upper Famennian Cleveland Shales of Late Devonian in Ohio. The type species is Gorgonichthys clarki. Description Gorgonichthys had sharp, pointed edges on the dental plates of the upper and lower jaws. With a headshield length of up to , it is estimated to have been comparable to the size of Dunkleosteus. Phylogeny Gorgonichthys is a member of the clade Aspinothoracidi, which belongs to the clade Pachyosteomorphi, one of the two major clades within Eubrachythoraci. It is closely related to the family Selenosteidae, and could possibly be included in that family. The cladogram below shows the phylogeny of Gorgonichthys: According to a 2022 Jobbins et al. study, Gorgonichthys was found to be more related to Heintzichthys than Gymnotrachelus, potentially making Gorgonichthys a member of Selenosteidae. References Arthrodires Arthrodire genera Placoderms of North America Paleontology in Ohio Famennian life Famennian genus first appearances Famennian genus extinctions