Microsteus

Microsteus is an extinct genus of small selenosteid arthrodire placoderms known from the Upper Frasnian Kellwasserkalk facies of Late Devonian Germany.^[1]: 96

Microsteus Temporal range: Late Frasnian[1]
Reconstruction of M. dubius
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	†Placodermi
Order:	†Arthrodira
Suborder:	†Brachythoraci
Family:	†Selenosteidae
Genus:	†Microsteus
Type species
Microsteus dubius Gross 1932
Species
Microsteus dubius Gross 1932 Microsteus angusticeps (Stensiö 1963) Microsteus gracilis (Stensiö 1963)
Synonyms
Parawalterosteus angusticeps Stensiö 1963 Parawalterosteus gracilis Stensiö 1963

There are three species, M. dubius (the type species), M. angusticeps, and M. gracilis. M. angusticeps differs from the type species in having a head with an angular profile, and M. gracilis differs from the other two species by being somewhat narrower in cross-section. Denison (1978) suggests that M. angusticeps and M. gracilis do not have enough differences from M. dubius to merit separate species status, but other authors, such as Rücklin 2011, treat the three as separate species.^[2]

M. angusticeps and M. gracilis originally composed the genus Parawalterosteus. However, Denison (1978) points out that the two species are not distinct from Microsteus, and synonymized Parawalterosteus with the former genus.