Gyrosteus

Gyrosteus is an extinct genus of very large ray-finned fish belonging to the family Chondrosteidae.[3] It comprises the type species, Gyrosteus mirabilis, which lived during the early Toarcian (Late Early Jurassic) in what is now northern Europe. A possible second species, "Gyrosteus" subdeltoideus, is known from otoliths.

Gyrosteus
Temporal range: Lower Toarcian Possible Bathonian record
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Acipenseriformes
Family: †Chondrosteidae
Genus: †Gyrosteus
Agassiz, 1843
Type species
†Gyrosteus mirabilis
[1] Agassiz 1844
Species
  • †"Gyrosteus" subdeltoideus[2]

Fossil remains of G. mirabilis have been recovered from the Whitby Mudstone Formation, United Kingdom, and from Ahrensburg erratics assemblage in Schleswig-Holstein, northern Germany.[4] It was mentioned but not formally described in subsequent publications and was left as a nomen nudum for more than 25 years.[5] Then in 1889 it was featured and formally described by Arthur Smith Woodward.[6] Gyrosteus was thought to be exclusive of the “British faunal province” and separated from the “Germanic faunal province” until the discovery of a hyomandibula in the baltic realm, mostly populated by Germanic fauna, which possibly implicates that Baltic region represented an interdigitating zone between both regions.[4]

The members of the genus Gyrosteus were massive fishes, with a maximum calculated standard length of 6 metres (20 ft) to 7 metres (23 ft), and with a reported hyomandibula reaching 50 centimetres (20 in).[7]

References
  1. Agassiz L. 1834. Recherches sur les Poissons Fossiles: Tome I. Neuchatel: Imprimerie de Petitpierre. 188
  2. Stinton, F.C.; Torrens, H.S. (1968). "Fish otoliths from the Bathonian of southern England. Palaeontology". 11 (2): 246–258. Retrieved 21 November 2021.
  3. Bemis, William E.; Findeis, Eric K.; Grande, Lance (1997). "An overview of Acipenseriformes". Environmental Biology of Fishes. 48 (1–4): 25–71. doi:10.1023/A:1007370213924. S2CID 24961905.
  4. Hornung, J. J.; Sachs, S. (2020). "First record of Gyrosteus mirabilis (Actinopterygii, Chondrosteidae) from the Toarcian (Lower Jurassic) of the Baltic region". PeerJ. 1 (1): 1–10. Retrieved 16 July 2021.
  5. Egerton, P. G.; Cole, E. W. W. (1837). "A Systematic and Stratigraphical Catalogue of the Fossil Fish in the Cabinets of Lord Cole and Sir Philip Grey Egerton: Together with an Alphabetical and Stratigraphical Catalogue of the Same Species, with References to Their Published Figures and Descriptions". Richard and John e. Taylor. 1 (1): 45–89.
  6. Woodward, A. S. (1889). "On the paleontology of sturgeons". Proceedings of the Geologists' Association. 11 (1): 24–32. doi:10.1016/S0016-7878(89)80044-6.
  7. Woodward, A.S. (1890). "The fossil sturgeon of the Whitby Lias". Naturalist. 15 (177): 101–107.
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