Cretoxyrhina

Cretoxyrhina mantelli was a large shark that lived about 100 to 82 million years ago, during the mid-Cretaceous period. It is commonly known as the Ginsu Shark.

Identification and preserved specimens
This shark was first identified by a famous Swiss Naturalist, Louis Agassiz in 1843, as Cretoxyhrina mantelli. However, the most complete specimen of this shark was discovered in 1890, by the fossil hunter Charles H. Sternberg, who published his findings in 1907. The specimen comprised a nearly complete associated vertebral column and over 250 associated teeth. This kind of exceptional preservation of fossil sharks is rare because a shark's skeleton is made of cartilage, which is not prone to fossilization. Charles dubbed the specimen Oxyrhina mantelli. This specimen represented a 20-foot-long (6.1 m) shark. It was excavated from Hackberry creek, Gove county, Kansas.[1]

In later years, several other specimens have also been found. One such specimen was discovered in 1891 by George Sternberg, and was stored in a Munich museum. This specimen was also reported to be 20 feet long, but was destroyed during a bombing raid on Munich in World War II.

Common name
Cretoxyhrina mantelli had no common name in the early literature and over 30 synonyms were assigned to it.[1] Since it fed by slicing its victims into bite-size pieces, paleontologists K. Shimada and M. J. Everhart gave it the name Ginsu Shark.[2] The word Ginsu refers to slicing and dicing.

Physical anatomy
The Ginsu shark is among the most well understood fossil sharks to date. Several preserved specimens have revealed a great deal of insight about the physical features and lifestyle of this ancient predatory shark.

Dentition
The fossil teeth of C. mantelli are up to 6 cm long,[3] curved, and smooth-edged, with a thick enamel coating.

The Ginsu shark had 34 teeth in its upper jaw and 36 teeth in lower jaw, in each row.[1]

The Ginsu Shark is believed to be a relative of the Great White Shark. Known specimens of the Ginsu Shark are about the same size as the largest recorded Great Whites Sharks.

Range
This shark lived in Cenomanian–Campanian seas worldwide, including in the Western Interior Seaway of North America.