when did the great white shark first appear
Great white shark The earliest known fossils of the great white shark are about 16 million years old, during the mid-Miocene epoch.[1] However, the phylogeny of the great white is still in dispute. The original hypothesis for the great white's origins is that it shares a common ancestor with a prehistoric shark, such as the C. megalodon. C. megalodon had teeth that were superficially not too dissimilar with those of great white sharks, but its teeth were far larger. Although cartilaginous skeletons do not fossilize, C. megalodon is estimated to have been considerably larger than the great white shark, estimated at up to 17 m (56 ft) and 59,413 kg (130,983 lb).[21] Similarities among the physical remains and the extreme size of both the great white and C. megalodon led many scientists to believe these sharks were closely related, and the name Carcharodon megalodon was applied to the latter. However, a new hypothesis proposes that the C. megalodon and the great white are distant relatives (albeit sharing the family Lamnidae). The great white is also more closely related to an ancient mako shark, Isurus hastalis, than to the C. megalodon, a theory that seems to be supported with the discovery of a complete set of jaws with 222 teeth and 45 vertebrae of the extinct transitional species Carcharodon hubbelli in 1988 and published on 14 November 2012.[22] In addition, the new hypothesis assigns C. megalodon to the genus Carcharocles, which also comprises the other megatoothed sharks; Otodus obliquus is the ancient representative of the extinct Carcharocles lineage.[23]
Greenland shark The Greenland shark (Somniosus microcephalus), also known as the gurry shark or grey shark, or by the Kalaallisut name eqalussuaq, is a large shark of the family Somniosidae ("sleeper sharks"), closely related to the Pacific and southern sleeper sharks.[2] The distribution of this species is mostly restricted to the waters of the North Atlantic Ocean and Arctic Ocean.