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Fossil genus of fishes From Wikipedia, the free encyclopedia
Sphenodus is an extinct genus of shark. It is placed as a member of the extinct family Orthacodontidae, which is either considered to be a member of the extinct order Synechodontiformes,[1] or the modern shark order Hexanchiformes.[2] 29 species have been described,[3] though some of these are likely synonyms, which span from the Early Jurassic (Sinemurian) to Paleocene (Danian).[2] Most species are only known from isolated teeth,[2] though the species Sphenodus macer and Sphenodus nitidus from the Late Jurassic of Germany are known from skeletons. These suggest that it was relatively large, with a body length of 2–3 metres (6.6–9.8 ft), with a fusiform body with a single dorsal fin placed posteriorly without a fin spine.[1] The teeth of Sphenodus consist of a single long, narrow central cusp, with much smaller lateral cusplets.[2] Species of Sphenodus are thought to have been actively swimming predators.[1]
Sphenodus Temporal range: | |
---|---|
Skeleton of Sphenodus nitidus (SMNS 96844-7) from the Late Jurassic of Germany | |
Tooth of Sphenodus nitidus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Chondrichthyes |
Subclass: | Elasmobranchii |
Family: | †Orthacodontidae |
Genus: | †Sphenodus Agassiz, 1843 |
Type species | |
Lamna (Sphenodus) longidens Agassiz, 1843 |
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