between ages suggests that Cretoxyrhina may have become locally extinct in such areas over time until the genus as a whole went extinct. It has been noted that the decline of Cretoxyrhina coincides with the rise of newer predators such as Tylosaurus, suggesting that increasing pressure from competition with the mosasaur and other predators of similar trophic levels may have played a major contribution to Cretoxyrhinas decline and eventual extinction. Another possible factor was the gradual shallowing and shrinking of the Western Interior Seaway, which would have led to the disappearance of the pelagic environments preferred by the shark; this factor does not explain the decline and extinction of Cretoxyrhina elsewhere. It has been suggested that the extinction of Cretoxyrhina'' may have helped the further increase the diversity of mosasaurs. See also Prehistoric fish List of prehistoric cartilaginous fish Notes References External links Fact File from National Geographic Large Sharks in the Western Interior Sea Cretoxyrhinidae Albian genus first appearances Campanian genus extinctions Cretaceous sharks Late Cretaceous fish of Asia Cretaceous fish of Europe Late Cretaceous fish of North America Mooreville Chalk Fossil taxa described in 1843 Fossil taxa described in 1958