Article · Wikipedia archive · Last revised Jul 14, 2026

Hadrosteus

Hadrosteus is an extinct monospecific genus of large arthrodire placoderm from the Late Frasnian Kellwasserkalk facies of Bad Wildungen, Germany. It had large, double-pronged inferognathals, 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.

Last revised
Jul 14, 2026
Read time
≈ 1 min
Length
264 w
Citations
4
Source
Hadrosteus
Temporal range: Late Devonian: Frasnian,
Artist's reconstruction
Scientific classification Edit this classification
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

References

References

  1. 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.