Watsonosteus is an extinct genus of coccosteid arthrodire placoderm from the Late Givetian stage of the Middle Devonian period. Fossils are found in the Orkney Islands, Scotland. It was a small placoderm with a total body length of 57 cm (22 in),[1] with the largest individuals reaching lengths of 1 m (39 in).[2] It is one of the few arthrodires for which complete body fossils are known.
| Watsonosteus Temporal range: Middle Devonian: Late Givetian,
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| Watsonosteus fossil specimen | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | †Placodermi |
| Order: | †Arthrodira |
| Suborder: | †Brachythoraci |
| Family: | †Coccosteidae |
| Genus: | †Watsonosteus Miles & Westoll, 1963 |
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Phylogeny edit
Watsonosteus is a member of the family Coccosteidae, which belongs to the clade Coccosteomorphi, one of the two major clades within Eubrachythoraci. The cladogram below shows the phylogeny of Watsonosteus:[3]
References edit
- ^ Engelman, Russell K. (2023). "A Devonian Fish Tale: A New Method of Body Length Estimation Suggests Much Smaller Sizes for Dunkleosteus terrelli (Placodermi: Arthrodira)". Diversity. 15 (3). 318. doi:10.3390/d15030318.
- ^ Newman, Michael J.; Blaauwen, Jan; Burrow, Carole; Jones, Roger (January 2021). "Earliest vertebrate embryos in the fossil record (Middle Devonian, Givetian)". Palaeontology. 64 (1): 21–30. Bibcode:2021Palgy..64...21N. doi:10.1111/pala.12511. S2CID 225001446.
- ^ 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.