Heterosteidae

Heterosteidae (also known as Heterostiidae^[1][2]) is an extinct family of moderately large to giant, flattened, benthic arthrodire placoderms with distinctive, flattened, triangular skulls that are extremely broad posteriorly, but become very narrow anteriorly.^[3]

Heterosteidae Temporal range: Devonian: Emsian to Givetian, 407.6–382.7 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Comparison of genera
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	†Placodermi
Order:	†Arthrodira
Suborder:	†Brachythoraci
Clade:	†Eubrachythoraci
Clade:	†Pachyosteomorphi
Superfamily:	†Dunkleosteoidea
Family:	†Heterosteidae Jaekel, 1903
Genera
Herasmius Heterosteus Yinostius

Heterosteidae belongs to the superfamily Dunkleosteoidea, a relative of the giant Dunkleosteus, as shown in the cladogram below:^[1]

Dunkleosteoidea	Eastmanosteus calliaspis Eastmanosteus pustulosus Kiangyousteus yohii Golshanichthys asiatica Westralichthys uwagedensis Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterostiidae Heterosteus ingens Yinosteus major

Genera

Herasmius Orvig, 1969

Heterosteus Asmuss, 1856

Yinostius J. Wang & N. Wang, 1984

References

1. 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.
2. Schultze, Hans-Peter; Cumbaa, Stephen L. (26 April 2017). "A new Early Devonian (Emsian) arthrodire from the Northwest Territories, Canada, and its significance for paleogeographic reconstruction". Canadian Journal of Earth Sciences. 54 (5): 461–476. Bibcode:2017CaJES..54..461S. doi:10.1139/cjes-2017-0013. hdl:1807/76893.
3. Denison, Robert (1978). Placodermi Volume 2 of Handbook of Paleoichthyology. Stuttgart New York: Gustav Fischer Verlag. p. 65. ISBN 978-0-89574-027-4.