''Kimbryanodus'' is a genus of extinct ptyctodontid

placoderm Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos'''Plate (animal anatomy), plate' and δέρμα 'derma'''skin') are vertebrate animals of the class (biology), class Placodermi, an extinct group of prehistoric fish known from Pal ...

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

from the

Frasnian The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

.These placoderms can be told apart from others due to the large eyes, crushing tooth plates, long bodies, reduced armor, and a superficial resemblance to

holocephalid Holocephali (Sometimes spelled Holocephala; Romanization of Greek, Greek for "complete head" in reference to the fusion of Palatoquadrate, upper jaw with the rest of the skull) is a Subclass (biology), subclass of Chondrichthyes, cartilaginous fi ...

fish. The group is so far the only Placoderms known with

sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

features. The fossils occur as small three dimensional isolated plates. Because of these new specimens the Ptyctodontid grouping got a taxonomic classification, it found that the genus ''

Rhamphodopsis ''Rhamphodopsis'' is a genus of extinct ptyctodont placoderm from the Middle Devonian Old Red Sandstone of Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third o ...

'' to be the most basal

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

. They are divided by having the more basal taxa having a median dorsal spine, a simple spinal plate, and a simple V-shaped overlap of the anterior lateral and the anterior dorsolateral plates.

References

{{Taxonbar, from =Q110205006 Ptyctodontids