Delphinosaurus

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Delphinosaurus
Temporal range: Early-Late Cretaceous, 103–98  Ma
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Delphinosaurus

Eichwald, 1853
Binomial name
Delphinosaurus kiprijanoffi
Eichwald, 1853

Delphinosaurus is a dubious genus of ophthalmosaurid ichthyosaur from Albian-Cenomanian deposits in the Kursk region of European Russia.

Contents

Merriam (1905) erected Delphinosaurus for the Late Triassic ichthyosaur Shastasaurus perrini from California, but because Delphinosaurus was already in use, the replacement name Californosaurus was erected. [1]

Classification

Eichwald (1853) erected Delphinosaurus for eight mandible fragments, twelve teeth, one rib, two centra, one humerus and one epipodial from the iron-rich sands of the Kursk area dating to the Albian–Cenomanian boundary. He classified the remains as those of amphibians, because of the presence of dolphin and reptile features, suggesting an intermediate form in between these groups, hence the name. [2] Later, however, he recognized Delphinosaurus as being an ichthyosaur in an 1865 monograph. [3]

In the supplementary material for their paper explaining the extinction of ichthyosaurs, Fischer et al. (2016) treated Delphinosaurus as a dubious genus of ophthalmosaurid, raising the possibility that the hypodigm for D. kiprijanoffi is composite due to some teeth resembling Sisteronia , and the humerus being morphologically distinct from Sisteronia. [4]

See also

Related Research Articles

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Ophthalmosaurus is an ichthyosaur of the Jurassic period. Possible remains from the Cretaceous, around 145 million years ago, are also known. It was a relatively medium-sized ichthyosaur, measuring 4 m (13 ft) long and weighing 930–950 kg (2,050–2,090 lb). Named for its extremely large eyes, it had a jaw containing many small but robust teeth. Major fossil finds of this genus have been recorded in Europe with a second species possibly being found in North America.

Platypterygius is a historically paraphyletic genus of platypterygiine ichthyosaur from the Cretaceous period. It was historically used as a wastebasket taxon, and most species within Platypterygius likely are undiagnostic at the genus or species level, or represent distinct genera, even being argued as invalid. While fossils referred to Platypterygius have been found throughout different continents, the holotype specimen was found in Germany.

<i>Aegirosaurus</i> Extinct genus of reptiles

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<span class="mw-page-title-main">Ophthalmosauridae</span> Extinct family of reptiles

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<i>Maiaspondylus</i> Extinct genus of reptiles

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<i>Arthropterygius</i> Extinct genus of reptiles

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<i>Athabascasaurus</i> Extinct genus of reptiles

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<i>Acamptonectes</i> Extinct genus of ophthalmosaurid ichthyosaur known from England and Germany

Acamptonectes is a genus of ophthalmosaurid ichthyosaurs, a type of dolphin-like marine reptiles, that lived during the Early Cretaceous around 130 million years ago. The first specimen, a partial adult skeleton, was discovered in Speeton, England, in 1958, but was not formally described until 2012 by Valentin Fischer and colleagues. They also recognised a partial subadult skeleton belonging to the genus from Cremlingen, Germany, and specimens from other localities in England. The genus contains the single species Acamptonectes densus; the generic name means "rigid swimmer" and the specific name means "compact" or "tightly packed".

<span class="mw-page-title-main">Platypterygiinae</span> Extinct subfamily of reptiles

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<span class="mw-page-title-main">Ophthalmosaurinae</span> Extinct subfamily of reptiles

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<i>Sisteronia</i> Extinct genus of reptiles

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<i>Pervushovisaurus</i> Extinct genus of reptiles

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<span class="mw-page-title-main">Timeline of ichthyosaur research</span>

This timeline of ichthyosaur research is a chronological listing of events in the history of paleontology focused on the ichthyosauromorphs, a group of secondarily aquatic marine reptiles whose later members superficially resembled dolphins, sharks, or swordfish. Scientists have documented ichthyosaur fossils at least as far back as the late 17th century. At that time, a scholar named Edward Lhwyd published a book on British fossils that misattributed some ichthyosaur vertebrae to actual fishes; their true nature was not recognized until the 19th century. In 1811, a boy named Joseph Anning discovered the first ichthyosaur fossils that would come to be scientifically recognized as such. His sister Mary would later find the rest of its skeleton and would go on to become a respected fossil collector and paleontologist in her own right.

<i>Keilhauia</i> Extinct genus of reptiles

Keilhauia is a genus of ophthalmosaurid ichthyosaur, a type of dolphin-like, large-eyed marine reptile, from the Early Cretaceous shallow marine Slottsmøya Member of the Agardhfjellet Formation in Svalbard, Norway. The genus contains a single species, K. nui, known from a single specimen discovered in 2010 and described by Delsett et al. in 2017. In life, Keilhauia probably measured approximately 4 metres (13 ft) in length; it can be distinguished by other ophthalmosaurids by the wide top end of its ilium and the relatively short ischiopubis compared to the femur. Although it was placed in a basal position within the Ophthalmosauridae by phylogenetic analysis, this placement is probably incorrect.

References

  1. Hilton, R. P., (2003), Dinosaurs and other Mesozoic reptiles of California: University of California Press, 318pp.
  2. Eichwald, K. E. (1853). Einige paläontologische Bemerkungen über den Eisensand von Kursk. Bull. la Société Impériale des Nat. Moscou 2, 209–231.
  3. Eichwald, K. E. (1865). Lethaea Rossica ou Paléontologie de la Russie. Second Volume. Période Moyenne.).
  4. Fischer, V.; Bardet, N.; Benson, R.; Arkhangelsky, M.S.; Friedman, M. (2016). "Extinction of fish-shaped marine reptiles associated with reduced evolutionary rates and global environmental volatility". Nature Communications. 7: 10825. doi:10.1038/ncomms10825. PMC   4786747 . PMID   26953824.