A slow and modest shark that swam in shallow waters 165 million years ago was the ancestor of iconic creatures such as great white sharks and the megalodon.
The flat-bellied ancestor is finally connected to his famous descendants by a unique tooth structure that is only shared by these mackerel sharks.
Unlike other sharks, these teeth, the inside of which – beneath the surface of the enamel – is made entirely of a bone-like dentin that is normally found only in the roots of teeth.
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A slow and modest shark that swam in shallow waters 165 million years ago was the ancestor of iconic creatures such as great white sharks, depicted and megalodon
WHAT IS DIFFERENT ABOUT MACKEREL SHARK TEETH?
For most sharks, the crown of the tooth consists mainly of compact orthodentine.
This is the same material found in human teeth.
The roots of shark teeth are usually made from a more spongy, bone-like material called osteodentine.
In some sharks, osteodentine can also occur in the crown of the teeth.
However, mackerel shark teeth have no orthodentine and have replaced it all with osteodentine.
This structure is unique for these sharks – including large whites, mako sharks and the extinct reemoth megalodon – and their ancestors.
Paleontologist Patrick Jambura from the University of Vienna and his colleagues used high-resolution scans to examine the teeth composition of both large white and other related species known as mackerel sharks.
These animals – including the fastest swimming mako shark and the extinct megalodon, one of the largest predators ever to have lived – have unusually structured teeth, researchers found.
Just like humans, sharks have teeth consisting of two types of material, with a hard outer surface of hypermineralized tissue – we have enamel, sharks have enameloid – and a core of bone tissue, called dental bone, which itself comes in two forms.
Of these, human teeth contain only the compact orthodentine, which in sharks is limited to the crown of the tooth, above the gums.
In contrast, osteodentine is spongy in appearance, similar to the inside of bone.
In sharks, osteodentine usually appears in the roots of the teeth, with each of the teeth attached to the jaw, although in some cases osteodentine is also known in the crown.
In the mackerel sharks, however, the researchers found that osteodentine had spread from the root of each tooth in the crown and had completely replaced all orthodentine – a highly peculiar configuration.
& # 39; Orthodentine is known for almost all vertebrate animals – from fish to mammals, including all modern sharks, except the mackerel sharks & # 39 ;, said Mr. Jambura.
Paleontologist Patrick Jambura from the University of Vienna and his colleagues used high-resolution scanning technology to investigate the teeth composition of both large white and other related species known as mackerel sharks
These animals – including the fastest swimming Mako shark; the extinct Megalodon, one of the greatest predators ever to have lived; and the crocodile shark, whose jaw is depicted – has unusually structured teeth, researchers found
In addition to members of the mackerel sharks, researchers also examined the teeth of a small fossil shark known as Palaeocarcharias stromeri, which was known to live 165 million years ago, during the middle of the Jurassic period.
Palaeocarcharias has long been a mystery to paleontologists.
Although the shape of his body resembles that of the modern carpet shark – so named after the ornate patterns that are often found on their backs – he had teeth that look like teeth and are much more like those of mackerel sharks, such as large white or megalodon .
Nevertheless, Palaeocarcharias seems to have little in common with current mackerel sharks, a three-meter long and slow shark that would have lived near the seabed and probably hunted small fish in shallow waters.
In addition to mackerel sharks, researchers also examined the teeth of a small fossil shark known as Palaeocarcharias stromeri, pictured, which was known to live 165 million years ago, during the middle of the Jura period.
However, when Mr. Jambura and his colleagues analyzed the fossil teeth of the shark, they discovered that the tooth structure dominated by osteodentine occurs only in mackerel sharks.
This shared tooth structure strongly suggests that the relatively modest Jurassic-age animal gave rise to the most iconic sharks such as the terrifying big white or the extinct giant that was megalodon.
& # 39; The discovery of this unique tooth structure in the fossae shark Palaeocarcharias strongly indicates that we have found the oldest known ancestor of the great white shark & # 39 ;, said Mr. Jambura.
& # 39; Even this charismatic basking shark started with a little bit. & # 39;
The full findings of the study were published in the journal Scientific reports.
WHAT IS THE MEGALODON?
The megalodon, which means big tooth, lived between 15.9 and 2.6 million years ago.
C. megalodon is considered to be one of the largest and most powerful predators in the history of vertebrates and fossil remains suggesting that it has grown to 18 meters in length.
It seems that the monster looked like a more stocky version of today's much-feared great white shark and weighed up to 100 tons.
Megalodon is known for petrified vertebrae and teeth, which are triangular and have a diagonal length of 20 cm.
Famous fossil hunter Vito & # 39; Megalodon & # 39; Bertucci took almost 20 years to reconstruct the largest collector of a megalodon – the largest ever assembled – measuring 11 ft wide and almost 9 m high.
The colossal mouth of the Megalodon is said to have produced a force of only 10.8 to 18.2 tons.
The old shark has been described as a super predator, because it can swim at high speeds and kill a wide range of prey such as sea turtles and whales, fast in its strong jaws.
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