Dinichthys (from Greek:δεινός deinós, 'terrible' and Greek:ἰχθύς ichthys 'fish') is an extinct monospecific genus of large marine arthrodire placoderm from the Late Devonian (Famennian stage) measuring around 3 metres (9.8ft) long. Fossils were recovered from the Ohio Shale Formation along the Olentangy River in Delaware County, Ohio.

Classification History

Life restoration

Dinichthys was originally described in 1868 by John Newberry on the basis of an incomplete skull roof and mandibles (holotype AMNH 81). Subsequently, many unrelated large arthrodires were originally classified together within this genus, including species now assigned to Dunkleosteus, Eastmanosteus, and Titanichthys. Notably, the type species of Dunkleosteus was originally described as Dinichthys terrelli by Newberry in 1873, and was later separated into Dunkleosteus by Jean-Pierre Lehman in 1956. Dunkleosteus was still thought to be closely related to Dinichthys, and they were grouped together in the family Dinichthyidae. However, in the 2010 Carr & Hlavin phylogenetic study, Dunkleosteus and Dinichthys were found to belong to two separate clades. Carr & Hlavin resurrected the family Dunkleosteidae and placed Dunkleosteus, Eastmanosteus, and a few other genera from Dinichthyidae within it. Dinichthyidae, in turn, is left a monospecific family and dismissed as a family grouping, and the genus Dinichthys is now considered a monotypic genus, containing only the type species, D. herzeri.

Phylogeny

Dinichthys is a member of the clade Aspinothoracidi, which belongs to the clade Pachyosteomorphi, one of the two major clades within Eubrachythoraci. The cladogram below shows the phylogeny of Dinichthys:

EubrachythoraciCoccosteomorphi Pachyosteomorphi Rhachiosteus pterygiatus Dunkleosteoidea Eastmanosteus calliaspis Eastmanosteus pustulosus Kiangyousteus yohii Golshanichthys asiatica Westralichthys uwagedensis Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major Aspinothoracidi Tapinosteus heintzi Bullerichthys fascidens Kendrickichthys cavernosus Bruntonichthys multidens Dinichthys herzeri Hadrosteus rapax Gorgonichthys clarki Selenosteidae Heintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus
Coccosteomorphi
PachyosteomorphiRhachiosteus pterygiatus Dunkleosteoidea Eastmanosteus calliaspis Eastmanosteus pustulosus Kiangyousteus yohii Golshanichthys asiatica Westralichthys uwagedensis Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major Aspinothoracidi Tapinosteus heintzi Bullerichthys fascidens Kendrickichthys cavernosus Bruntonichthys multidens Dinichthys herzeri Hadrosteus rapax Gorgonichthys clarki Selenosteidae Heintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus
Rhachiosteus pterygiatus
Dunkleosteoidea Eastmanosteus calliaspis Eastmanosteus pustulosus Kiangyousteus yohii Golshanichthys asiatica Westralichthys uwagedensis Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major Aspinothoracidi Tapinosteus heintzi Bullerichthys fascidens Kendrickichthys cavernosus Bruntonichthys multidens Dinichthys herzeri Hadrosteus rapax Gorgonichthys clarki Selenosteidae Heintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus
DunkleosteoideaEastmanosteus calliaspis Eastmanosteus pustulosus Kiangyousteus yohii Golshanichthys asiatica Westralichthys uwagedensis Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major
Eastmanosteus calliaspis
Eastmanosteus pustulosus Kiangyousteus yohii Golshanichthys asiatica Westralichthys uwagedensis Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major
Eastmanosteus pustulosus Kiangyousteus yohii
Eastmanosteus pustulosus
Kiangyousteus yohii
Golshanichthys asiatica Westralichthys uwagedensis Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major
Golshanichthys asiatica
Westralichthys uwagedensis Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major
Westralichthys uwagedensis
Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major
Dunkleosteus raveri Dunkleosteus terrelli
Dunkleosteus raveri
Dunkleosteus terrelli
Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major
Dunkleosteus amblyodoratus
HeterostiidaeHeterosteus ingens Yinosteus major
Heterosteus ingens
Yinosteus major
AspinothoracidiTapinosteus heintzi Bullerichthys fascidens Kendrickichthys cavernosus Bruntonichthys multidens Dinichthys herzeri Hadrosteus rapax Gorgonichthys clarki Selenosteidae Heintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus
Tapinosteus heintzi
Bullerichthys fascidens Kendrickichthys cavernosus Bruntonichthys multidens Dinichthys herzeri Hadrosteus rapax Gorgonichthys clarki Selenosteidae Heintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus
Bullerichthys fascidens Kendrickichthys cavernosus Bruntonichthys multidens
Bullerichthys fascidens
Kendrickichthys cavernosus Bruntonichthys multidens
Kendrickichthys cavernosus
Bruntonichthys multidens
Dinichthys herzeri Hadrosteus rapax Gorgonichthys clarki Selenosteidae Heintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus
Dinichthys herzeri
Hadrosteus rapax Gorgonichthys clarki Selenosteidae Heintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus
Hadrosteus rapax
Gorgonichthys clarki Selenosteidae Heintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus
Gorgonichthys clarki
SelenosteidaeHeintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus
Heintzichthys gouldii
Pachyosteus bulla
Gymnotrachelus hydei
Stenosteus angustopectus
Brachyosteus dietrichi
Melanosteus occitanus Rhinosteus parvulus
Melanosteus occitanus
Rhinosteus parvulus