Protosqualus
| Protosqualus Temporal range: Cretaceous, | |
|---|---|
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| Drawing of a Protosqualus argentinensis tooth | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Division: | Selachii |
| Order: | Squaliformes |
| Family: | Squalidae |
| Genus: | †Protosqualus Cappetta, 1977 |
| Type species | |
| †Protosqualus sigei Cappetta, 1977 | |
| Other species | |
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Protosqualus ("primitive Squalus") is an extinct genus of dogfish shark known from fossils found in Cretaceous rocks in Europe, Asia, Antarctica, Australia, and South America. The type species is Protosqualus sigei, which was found around an Albian-aged deposit in France. There are six species, which can be differentiated by distinct features in their teeth. Some species, such as P. barringtonensis, exhibit high levels of heterodonty. The oldest specimens are from the Speeton Clay Formation. Protosqualus teeth are quite common in the Grey Chalk deposit of England. The genus went extinct at the end of the Cretaceous during the Cretaceous–Paleogene extinction event, with the last species in the genus being Protosqualus argentinensis from southern Argentina as well as possibly being from earlier deposits in India.