Xenacanthus | |
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Skeletal reconstruction of Xenacanthus decheni | |
Life restoration of Xenacanthus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Chondrichthyes |
Subclass: | Elasmobranchii |
Order: | †Xenacanthida |
Family: | †Xenacanthidae |
Genus: | †Xenacanthus Beyrich, 1848 |
Type species | |
Xenacanthus decheni | |
Species | |
See text | |
Synonyms | |
Pleuracanthus Agassiz 1837 |
Xenacanthus (from Ancient Greek ξένος, xénos, 'foreign, alien' + ἄκανθος, akanthos, 'spine') is a genus of prehistoric xenacanths. Fossils of various species have been found worldwide.
Xenacanthus had a number of features that distinguished it from modern sharks. This freshwater fish was usually about one meter (3.3 feet) in length,[1] and never longer than 2 m (6.6 ft).[2] The dorsal fin was ribbonlike and ran the entire length of the back and round the tail, where it joined with the anal fin. This arrangement resembles that of modern conger eels, and Xenacanthus probably swam in a similar manner. A distinctive spine projected from the back of the head and gave the genus its name. The spike has even been speculated to have been venomous, perhaps in a similar manner to a sting ray. The teeth had an unusual "V" shape, and it probably fed on small crustaceans and heavily scaled palaeoniscid fishes.[3]
As with many xencanths, Xenacanthus is mainly known because of fossilised teeth and spines.
Fossils are known from the Carboniferous-Permian of North America, Europe, and South America. Triassic species have been moved into the separate genus Mooreodontus.[4][5][6]