Cardabiodon

Cardabiodon (; meaning 'Cardabia tooth') is an extinct genus of large mackerel shark that lived about 95 to 91 million years ago (Ma) during the Cenomanian to Turonian of the Late Cretaceous. It is a member of the Cardabiodontidae, a family unique among mackerel sharks due to differing dental structures, and contains the two species C. ricki and C. venator. Cardabiodon fossils have been found in Australia, North America, England, and Kazakhstan. It was likely an antitropical shark that inhabited temperate neritic and offshore oceans between 40° and 60° paleolatitude, similar to the modern porbeagle shark.

One of the largest sharks of its time, Cardabiodon has been estimated to measure up to 5.5 metres (18 ft) in length. It may have been an apex predator in its ecosystem and likely used its large, robust teeth and fast swimming capabilities to prey on a variety of marine animals including plesiosaurs, ichthyosaurs, and other large fish. Cardabiodon also had a very heavy and stocky body. Scientists have been partially successful in calculating the life history of the shark. At birth, Cardabiodon individuals measured between 41–76 centimetres (16–30 in) in length and reached sexual maturity at around five to seven years of age, but no conclusive estimates on the maximum lifespan of Cardabiodon have been made.

Discovery and naming

Cardabiodon was described from an associated fossil discovered in the Southern Carnarvon Basin of the Gearle Siltstone which is located within Cardabia, a cattle station in Western Australia, by paleontologist Mikael Siverson, who published his findings in 1999.