Biology:Hadrosteus

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Hadrosteus
Temporal range: Late Devonian: Frasnian, 382.7–372.2 Ma
Artist's reconstruction
Scientific classification e
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