''Taemasosteus'' is an extinct genus of

arthrodire Arthrodira (Greek for "jointed neck") is an Order (biology), order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetratin ...

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 ...

. Its fossils have been found in

Emsian The Emsian is one of three faunal stages in the Early Devonian Epoch. It lasted from 410.62 ±1.95 million years ago to 393.47 ±0.99 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It is named after ...

aged Ageing (or aging in American English) is the process of becoming older until death. The term refers mainly to humans, many other animals, and fungi; whereas for example, bacteria, perennial plants and some simple animals are potentially biologi ...

marine strata in

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

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 ...

. It contains two species, ''T. novaustrocambricus'', and ''T. maclartiensis''. The genus (and a monotypic family, "Taemasosteidae") was originally erected on the basis of "an imperfect" paranuchal, though, more specimens were found, eventually leading "Taemasosteidae" to be subsumed into Buchanosteidae. Even so, the reconstructed anatomy leads some researchers to conclude that ''Taemasosteus'' is close to the ancestry of

Homostiidae Homostiidae (alternatively spelled Homosteidae) is a family (biology), family of flattened arthrodire placoderms from the Early Devonian, Early to Middle Devonian. Fossils appear in various strata in Europe, Russia, Morocco, Australia, Canada and ...

. These researchers place ''Taemasosteus'' as the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

of Homostiidae (or a select group of the better known homostiid genera) within the

taxon 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 ...

Migmatocephala Migmatocephala is a clade of placoderm fish within the suborder Brachythoraci. Migmatocephala includes the homostiids Taemasosteus?, '' Tityosteus'', ''Antineosteus'', '' Atlantidosteus'', and '' Homosteus''. Phylogeny The cladogram A ...

References

Buchanosteidae Placoderms of Australia Arthrodire genera {{Placoderm-stub