''Hemipristis serra'' is an extinct species of

weasel shark The weasel sharks are a family, the Hemigaleidae, of ground sharks found from the eastern Atlantic Ocean to the continental Indo-Pacific. They are found in shallow coastal waters to a depth of . Most species are small, reaching no more than ...

which existed during the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

epoch. It was described by

Louis Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he rec ...

in 1843. While today's snaggletooth shark is not very large or dangerous, ''Hemipristis serra'', which lived in the Atlantic Ocean during the Oligocene and Miocene, was considerably larger than its modern-day relative and had much larger teeth. Its total length is estimated to be . Marks made by the teeth of ''H. serra'' are often found on the bones of the manatee '' Metaxytherium'' leading some scientists to hypothesize that ''H. serra'' specialized in preying on these sirenians. In the Gatun Formation of Panama, ''H. serra'' was contemporary with pups of the large lamniform shark '' Otodus megalodon'', and both it and the great hammerhead are theorized to have preyed on the pups of this larger shark due to their presence within the formation. The unusual teeth of ''Hemipristis serra'' are highly prized by collectors because they are often found in sediments in Southern Florida that yield extremely colorful fossil shark teeth. Their outstandingly large serrations make it a favorite and unique collectible fossil. Little else is known about the general appearance of ''H. serra'', as there are no known fossils preserving its cartilaginous skeleton at present.

References

Hemipristis Miocene sharks Miocene fish of North America Fossil taxa described in 1843 {{Shark-stub