Hemipristis

Name: Hemipristis
Phonetic: He-me-priss-tiss.
Named By: Louis Agassiz.
Synonyms: Dirrhizodon,‭ ‬Heterogalaeus.
Classification: Chordata,‭ ‬Chondrichthyes,‭ ‬Elasmobranchii,‭ ‬Carcharhiniformes,‭ ‬Hemigaleidae.
Species: H. serra, H. curvatus, H. wyattdurhami, H. elongata.
Diet: Carnivore.
Size: Largest living species up to 2.4 meters long, largest H. serra specimens estimated to be about 7 meters long.
Known locations: Worldwide.
Time period: Oligocene to Miocene.
Fossil representation: Teeth.

       Hemipristis is a genus of weasel shark which includes the extinct species H.‭ ‬serra,‭ ‬H.‭ ‬curvatus and H.‭ ‬wyattdurhami,‭ ‬although the most popular species by far is H.‭ ‬serra.‭ ‬The last surviving member of the Hemipristis genus is H.‭ elongata,‭ ‬better known as the Snaggletooth shark. ‭H.‭ ‬serra seems to have been a particularly large species of Hemipristis,‭ ‬with the size of the teeth and jaw reconstructions of H.‭ ‬serra being roughly three times larger than the modern species H.‭ ‬elongata.‭ ‬Ergo,‭ ‬if the bite of a large H.‭ ‬serra was three times larger than a big H.‭ ‬elongata,‭ ‬then it is within the realms of possibility that a large H.‭ ‬serra would also be three times as long as a large H.‭ ‬elongata.‭ ‬With a large H.‭ ‬elongata measuring about two hundred and forty centimetres long,‭ ‬this would make a large H.‭ ‬serra a little over seven meters long,‭ ‬bigger than the largest recorded great white shark.‭ ‬In all seriousness though this is not that much a stretch of the imagination,‭ ‬as H.‭ ‬serra was swimming in the oceans at the same time as even bigger sharks such as C.‭ ‬angustidens,‭ ‬C.‭ ‬chubutensis,‭ ‬and of course the mighty C.‭ ‬megalodon!
       Hemipristis sharks are noted for having slim pointed teeth in their lower jaws and having broader triangular teeth in the upper jaws.‭ ‬Although this may seem curious it is actually a simple arrangement that allows the lower teeth to pierce the flesh of prey and holding it in place while the upper teeth saw through with their serrations.‭ ‬This allows Hemipristis to remove bite sized chunks from the bodies of large prey.‭ ‬The large size of H.‭ ‬serra meant that it could prey upon larger animals,‭ ‬a statement that is corroborated by the presence of Hemipristis tooth marks upon the bones of mammalian sirenians such as manatees.
       Hemipristis serra teeth are very popular collectors‭’ ‬items on the fossil market due to their colouration which makes them quite unique when compared with the teeth of other shark species.

Further reading
- Quantifying a possible Miocene Phyletic change in Hemipristis (chondrichthyes) teeth. - Palaeontologia Electronica. - Richard E. Chandler, Karen E. Chiswell, and Gary D. Faulkner - 2006.



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