Stenosteus

Stenosteus is an extinct monospecific genus of medium-sized selenosteid arthrodire placoderms of the Late Devonian period known from the Upper Famennian Cleveland Shale of Ohio. Estimated skull lengths range from 6 to 9 centimeters^[1] Most fossils of Stenosteus have been scraps of armor and portions of tooth-plates suggestive of Selenosteus. In 1996, enough material of a new species, S. angustopectus, was recovered to allow a reconstruction of armor that resembles that of Selenosteus.^[2]

Stenosteus Temporal range: Late Devonian: Famennian, 371.1–359.3 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Stenosteus angustopectus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	†Placodermi
Order:	†Arthrodira
Suborder:	†Brachythoraci
Family:	†Selenosteidae
Genus:	†Stenosteus Dean, 1901
Type species
Stenosteus glaber Dean, 1901
Species
S. glaber Dean, 1901 S. pertenius Branson, 1911 S. angustopectus Carr, 1996

Phylogeny

Stenosteus is a member of the family Selenosteidae 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 Stenosteus:^[3]

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. Denison, Robert (1978). Handbook of Paleoichthyology, Volume 2, Placodermi. New York: Gustav Fischer Verlage. p. 98. ISBN 9780895740274.
2. Carr, Robert (February 1996). "Stenosteus augustopectus sp. nov. from the Cleveland Shale (Famennian) of Northern Ohio with a Review of Selenosteid (Placodermi) Systematics". Kirtlandia. 49: 9–43.
3. 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.