Cretodus
| Cretodus Temporal range:
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|---|---|
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| Cretodus crassidens tooth from the Atco Formation of Texas | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Subdivision: | Selachimorpha |
| Order: | Lamniformes |
| Family: | †Pseudoscapanorhynchidae |
| Genus: | †Cretodus Sokolov, 1965 |
| Type species | |
| †Oxyrhina crassidens Dixon, 1850
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| Other species | |
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Cretodus is an extinct genus of mackerel sharks belonging to the proposed family Pseudoscapanorhynchidae.[1] It lived during the Late Cretaceous, approximately 100 to 89 million years ago.[2] The genus is best known from formations formed in the Western Interior Seaway, but is also known from the late Cretaceous of Europe, Africa, and possibly Asia. It is mainly known from isolated teeth and vertebral centra, though a few associated dentitions and spines have been found.[1] A virtually complete skeleton of the species C. crassidens was described in 2022, revealing it could reach large sizes.[3]
Species
Shimada & Everhart (2019) attributed the following species to the genus, asserting they were chronospecies belonging to three grades of crown broadness.[1]
- Cretodus longiplicatus
- Cretodus semiplicatus
- Cretodus gigantea
- Cretodus houghtonorum
- Cretodus crassidens
Description
Paleobiology
Until 2022, Cretodus was mainly known from isolated teeth. The discovery of a virtually complete skeleton suggests the genus possessed a body similar in shape and form to the modern tiger shark. Armed with a wide and laterally expanded head that was equipped with powerful jaws, Cretodus would have also possessed a stout body, and in at least in C. crassidens, it was capable of reaching a length of 9–11 m (30–36 ft), a size attained by later sharks of the Cenozoic, such as members of the genus Otodus. Its body shape suggests a moderate swimming speed and that it would likely have ambushed prey using short bursts of energy. Examination suggests that the lifespan of this shark could be a maximum of 64 years. The individual known from a complete skeleton was estimated to be roughly 23 years of age at the time of its death.[3]
Paleoecology
Cretodus was a predator that fed on large prey, and is suggested to have specialized in feeding on protostegid turtles, based on stomach contents found within the complete specimen. The distribution of fossils in C. crassidens suggests a largely cosmopolitan distribution and a preference for offshore areas in contrast with other species in the genus, which preferred habitats in shallower water.[3]
References
- ^ a b c Shimada, Kenshu; Everhart, Michael J. (2019-07-04). "A new large Late Cretaceous lamniform shark from North America, with comments on the taxonomy, paleoecology, and evolution of the genus Cretodus". Journal of Vertebrate Paleontology. 39 (4): e1673399. doi:10.1080/02724634.2019.1673399. ISSN 0272-4634. S2CID 209439997.
- ^ "ELASMO.COM Fossil Genera: Cretodus". www.elasmo.com. Retrieved 2020-08-13.
- ^ a b c Amalfitano, Jacopo; Dalla Vecchia, Fabio Marco; Carnevale, Giorgio; Fornaciari, Eliana; Roghi, Guido; Giusberti, Luca (2022-05-10). "Morphology and paleobiology of the Late Cretaceous large-sized shark Cretodus crassidens (Dixon,1850) (Neoselachii; Lamniformes)" (PDF). Journal of Paleontology: 1–23. doi:10.1017/jpa.2022.23. ISSN 0022-3360.