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Complete fossil from an enormous shark that lived alongside the dinosaur disclose crucial information about this enigmatic predator — including it being an ancient relative of thegreat whitened shark .
The shark , from the genusPtychodus , were first discovered in the mid - eighteenth C . Descriptions of this genus were largely found on their teeth — which could be nearly 22 column inch ( 55 centimeters)longand 18 inches ( 45 cm ) wide , and were adapted for crush shell — discover in numerous marine deposits see to theCretaceous period(145 million to 66 million years ago ) .
The “exceptionally preserved” fossil unearthed in a limestone quarry in northeastern Mexico.
Without the ability to examine a fully intact specimen , researchers had hotly debated what the shark ’s soundbox physique might look like — until now .
" The discovery of complete Ptychodus specimen is really exciting because it solves one of the most striking enigmas in vertebrate paleontology , " lead authorRomain Vullo , a researcher at Géosciences Rennes , told Live Science in an email .
In a study release Wednesday ( April 24 ) in the journalProceedings of the Royal Society B : Biological Sciences , researchers have described concluded fossils of the shark find in limestone quarry in Nuevo León , northeastern Mexico . Its schema was still fully preserved , and its physical structure shape suggests it hunted sea turtles — which could explicate its extinction around 76 million years ago as it was competing with other animals that deplete the same fair game .
The “exceptionally preserved” fossil unearthed in a limestone quarry in northeastern Mexico.
The specimens " show an exquisite preservation , " because they were deposited in a quiet expanse with no scavenger , Vullo said . " The carcasses of animals were speedily eat up in a cushy lime mud before being alone disjoint . "
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psychoanalysis of the fossils reveals this big predator belonged to the mackerel shark group ( Lamniformes ) , which includes great albumen ( Carcharodon genus Odontaspis ) , mako , and salmon shark . It grew to around 33 groundwork ( 10 meters ) long and is known for its massive , grinding tooth , which are unlike those we see in sharks today .
The enigmatic sharks are believed to have eaten large ammonites and sea turtles.
It was widely believed thatPtychodusfed on invertebrates from the ocean floor — the ancient relatives of clams and mussels . But the new fossils dispute that , revealing that this ancient shark had a streamlined body shape , indicating it was a fast - swimming oceanic piranha . " The new divulge dodo from Mexico indicate thatPtychoduslooked like the living porbeagle shark , " Vullo said , but with " unique grinding dentition . "
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This new information has lead the researchers to believe it raven on with child ammonites — a type of crustacean with a gruelling shell — and sea turtles .
" Ptychodusoccupied a exceptional ecological niche in Late Cretaceous seas , " Vullo sound out , because it was the only pelagic shark that was adapted to eating heavily - shell prey such as turtles . This may excuse why it died out around 10 million years before the defunctness event that ended the Cretaceous period . " Toward the end of the Cretaceous , these turgid sharks were likely in direct competition with some maritime reptiles ( mosasaurs ) targeting the same prey , " he said .
