Strongylosteus

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Strongylosteus
Temporal range: Early Toarcian 184–181  Ma
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Strongylosteus hindenburgi 1.jpg
Strongylosteus hindenburgi fossil, Staatliches Museum für Naturkunde Stuttgart
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Chondrosteiformes
Family: Chondrosteidae
Genus: Strongylosteus
Jaekel, 1929
Species:
S. hindenburgi
Binomial name
Strongylosteus hindenburgi
(Pompeckj, 1914)
Synonyms
  • Chondrosteus hindenburgi Pompeckj, 1914

Strongylosteus is an extinct genus of prehistoric ray-finned fish that lived during the early Toarcian age of the Early Jurassic epoch. [1] [2] Its type species is Strongylosteus hindenburgi (monotypy). It is related to modern sturgeon and paddlefish (Acipenseroidei). [2]

Contents

Discovery

Strongylosteus hindenburgi skull close-up Strongylosteus hindenburgi skull.JPG
Strongylosteus hindenburgi skull close-up

Strongylosteus hindenburgi is known from the Toarcian Posidonienschiefer Formation in southwestern Germany, specifically around Holzmaden and Dotternhausen. Initially identified by Pompeckj in 1914 as " Chondrosteus hindenburgi", hovewer the name was never formally published. Hauff (1921) mentioned it as a nomen nudum , and Hennig (1925) provided the first formal description, retaining the name but describing it in detail alongside additional specimens. [2] Jaekel (1929) later reassigned it to the new genus Strongylosteus, correcting its taxonomic position. [3]

Since the 1925 description, over a dozen specimens, including isolated bones and partial skeletons, have been noted in various museum collections, though many remain undescribed or misidentified. This include a juvenile specimen under one meter long, present in the Urwelt Museum Hauff, awaiting formal study that may reveal ontogenic shifts. [4]

Synonym with other Genera

Life restoration Strongylosteus hindenburgiDB223.jpg
Life restoration

Strongylosteus has been suggested as a junior synonym of Chondrosteus , although there haven't been any new revisions about the status of the genus. [5] There have also been suggestions of synonymy between Strongylosteus hindenburgi and Gyrosteus mirabilis, mainly due to incomplete descriptions and preservation issues. [5] However, a 2025 analysis of a new skull roof from the Toarcian Whitby Mudstone corroborated Strongylosteus as a distinct genus based on skull roof differences, such as the number of rostral bones, the presence of a medial parietal, and variations in bone proportions and ornamentation patterns. The morphological distinctions are consistent across specimens, ruling out ontogenetic or intraspecific variation. Authors also pointed out that a modern redescription and phylogenetic analysis of both Strongylosteus and Gyrosteus is still necessary to clarify their evolutionary relationships within Chondrosteidae. [4]

Strongylosteus was a large member of the family Chondrosteidae and the largest non-reptilian marine vertebrate in the Posidonia Shale, with the largest articulated specimen (SMNS 7790) measuring 3.2 m in total length. [4]

See also

References

  1. 1 2 Sepkoski, Jack (2002). "A compendium of fossil marine animal genera". Bulletins of American Paleontology. 364: 560. Retrieved 2009-02-27.
  2. 1 2 3 Hennig, E. (1925). Chondrosteus Hindenburgi Pomp.---Ein «Stör» des württembergischen Ölschiefers (Lias\epsilon). Palaeontographica (1846-1933), 115–134.
  3. Jacket, O.; Jacket, O. (1929-01-01). "Die Morphogenie der altesten Wirbeltiere". Monographien zur Geologie und Palaeontologie Berlin. 3: 198.
  4. 1 2 3 Cooper, Samuel L. A.; Jacobs, Megan; Ferrari, Lucrezia; Martill, David M. (2025-01-09). "Skull roof anatomy of the Early Jurassic (Toarcian) acipenseriform †Gyrosteus mirabilis Woodward ex Agassiz, from Yorkshire, England, elucidates diversity of †Chondrosteidae" . Proceedings of the Geologists' Association. doi:10.1016/j.pgeola.2024.12.004. ISSN   0016-7878.
  5. 1 2 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.