''Enseosteus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of small selenosteid

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 ...

placoderms known from the Upper

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 th ...

Kellwasserkalk facies of Late

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

and

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...

. ''Enseosteus'' is very similar to the other Kellwasserkalk selenosteids, though, the type species, ''E. jaekelli'', has a bulbous, knob-shaped rostrum. Denison (1978) synonymizes the genera ''Ottonosteus'' (''O. jaekeli'' = ''E. hermanni'') and ''

Walterosteus ''Walterosteus'' is an extinct genus of small selenosteid arthrodire placoderms known from the Upper Frasnian Kellwasserkalk facies of Late Devonian Germany and Morocco. ''Walterosteus'' is very similar to the other Kellwasserkalk selenosteids ...

'' with ''Enseosteus'', claiming that the two genera are too similar to ''Enseosteus'' to merit separate genus status. Rücklin (2011) agrees with Denison's synonymizing of ''Ottonosteus'', but rejects Denison's synonymization of ''Walterosteus'', claiming how ''Walterosteus'' has a contact between the rostral plate and the pineal plate, which ''Enseosteus'' does not.

References

Selenosteidae Placoderms of Europe Placoderms of Africa {{Placoderm-stub