Extinct approximately 2.6 million years ago the Megalodon shark was the largest and most dangerous predatory shark that ever existed on Earth. Today the largest predatory shark is the white shark, she’s a man-eater. On account of its more than 400 attacks per person, a quarter of which have been fatal. In a recent study, researchers found that the two most dangerous predator of the deep sea actually came from a small, flat sharks living on the seabed about 165 million years ago.
Ancient ancestor of great white shark
Megalodon and great white (along with some other sharks) are members of the porbeagle, also known as lunoobraznye. One of the features that distinguishes these sharks from others is their teeth.
Shark teeth consist of a hard mineralized enamel shell surrounding a core of dentin. Dentin, in turn, usually consists of two types of tissue: orthodontia, which is limited to the crown of the tooth, and more tastevinage of osteodentin which is at the root and sometimes the crown of the tooth. When osteodentin optionally present in the crown, it serves to support orthodontia.
In the new study computed tomography of the teeth of the porbeagle showed that in her case, osteodentin spreads from root to crown, completely replacing orthodentic, thereby remaining the only type destinului tissue in the tooth.
After examining the fossils of extinct sharks, the scientists found that the only other shark, which was discovered the same teeth was known as Palaeocarcharias stromeri.
The skeleton of the fossil shark Palaeocarcharias stromeri
This shark was the size of not more than a meter in length, and were engaged in hunting for small fish, mostly in shallow water, 165 million years ago. She had a flat body resembling the body of modern carpet sharks. And even if it had nothing to do with mackerel sharks, it is, however, now considered to be their distant ancestor.
“The presence of teeth orthodontia is characteristic of almost all vertebrates – from fish to mammals, including all types of modern sharks, except for herring,” says study author Patrick Jambura from the University of Vienna. “The presence of this unique fabric in the teeth of fossil sharks Palaeocarcharias is a serious proof that we have discovered the oldest ancestor of the modern white shark.”
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