Diplognathus

Extinct genus of fishes

Diplognathus Temporal range: Late Famennian

Reconstructed as hadrosteids
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Placodermi
Order:	Arthrodira
Suborder:	Brachythoraci
Infraorder:	Coccosteina
Superfamily:	Dinichthyloidea
Family:	?Hadrosteidae
Genus:	Diplognathus Newberry, 1878
Type species
Diplognathus mirabilis Newberry, 1878
Species
D. mirabilis Newberry, 1878 D. larfargei Carr, 2005

Diplognathus is a genus of arthrodire placoderm from the Late Famennian Cleveland Shale of Late Devonian Ohio, known only from incomplete fragments of jaws and skulls.^[1] What fragments are known suggest that the living animals were large-eyed piscivores with weak, but widely gaping jaws. D. mirabilis is thought to be fairly large, with infragnathals up to 45 centimeters in length. The second species, D. larfargei, was much smaller, with inferognathals averaging about 4 centimeters in length.^[2]

In 1967, Obruchev placed this genus within Hadrosteidae, on the basis of how the two genera have similar denticle ("teeth") patterns of the inferognathals, though Denison (1978) contested this placement, preferring to leave the taxon as Arthrodira incertae sedis.

References

^ Denison, Robert (1978). Placodermi Volume 2 of Handbook of Paleoichthyology. Stuttgart New York: Gustav Fischer Verlag. p. 105. ISBN 978-0-89574-027-4.
^ CARR, ROBERT K.; GARY L. JACKSON (2005). "Diplognathus lafargei sp. nov . From the Antrim Shale (Upper Devonian) of the Michigan Basin, Michigan, U.S.A." (PDF). Revista Brasileira de Paleontologia. 8 (2): 019–116 (113). doi:10.4072/rbp.2005.2.03.

"Placodermi"

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata

Gnathostomata

see Gnathostomata
Placodermi	see below↓

Placodermi

Acanthothoraci *

Hagiangella
Palaeacanthaspidae*	Arabosteus Dobrowlania Kimaspis Kolymaspis Kosoraspis Palaeacanthaspis Radotina Romundina Sudaspis Tlamaspis
Weejasperaspididae	Murrindalaspis Weejasperaspis

Petalichthyida

Diandongpetalichthys Neopetalichthys
Quasipetalichthyidae	Eurycaraspis Pauropetalichthys Quasipetalichthys
Macropetalichthyidae	Ellopetalichthys Epipetalichthys Lunaspis Macropetalichthys Notopetalichthys Shearsbyaspis Tongdzuylepis Wijdeaspis