Biology:Hadrosteus

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Hadrosteus
Temporal range: Late Devonian: Frasnian, 382.7–372.2 Ma
Hadrosteus rapax.jpg
Artist's reconstruction
Scientific classification e
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Placodermi
Order: Arthrodira
Suborder: Brachythoraci
Clade: Eubrachythoraci
Clade: Pachyosteomorphi
Clade: Aspinothoracidi
Genus: Hadrosteus
Gross, 1932
Species
  • Hadrosteus rapax Gross, 1932 (type)

Hadrosteus is an extinct monospecific genus of large arthrodire placoderm from the Late Frasnian (Late Devonian) Kellwasserkalk facies of Bad Wildungen, Germany .[1] It had large, double-pronged inferognathals (lower jawbones), and serrated edges along its mandible, strongly suggesting that it was a fish-eating predator. The head had a triangular snout, and the trunkshield was short, but high, with a median dorsal plate that was broader than wide. The average skull length is about 16 centimeters.[1]

Etymology

The type species Hadrosteus rapax means "Rapacious Strong-Bone".[1]

Phylogeny

Hadrosteus 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 Hadrosteus:[2]

Eubrachythoraci 

Coccosteomorphi

 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

References

  1. 1.0 1.1 1.2 Denison, Robert (1978). Placodermi Volume 2 of Handbook of Paleoichthyology'. Stuttgart New York: Gustav Fischer Verlag. pp. 89–90. ISBN 978-0-89574-027-4. 
  2. Zhu, You-An; Zhu, Min; Wang, Jun-Qing (1 April 2016). "Redescription of Yinostius major (Arthrodira: Heterostiidae) from the Lower Devonian of China, and the interrelationships of Brachythoraci". Zoological Journal of the Linnean Society 176 (4): 806–834. doi:10.1111/zoj.12356. ISSN 0024-4082. 

Wikidata ☰ Q5638086 entry