The tiger shark is a person of the major predatory sharks acknowledged currently. This shark is a cosmopolitan species transpiring in all oceans around the globe. It is characterised by a striped pattern on its again, which is nicely marked in juveniles but usually fades in older people.
The fossil record of fashionable sharks reaches back again to the Permian, about 295 million a long time in the past. Finish fossil shark skeletons are pretty scarce — the skeleton, which consists practically fully of cartilage, is only preserved under pretty unique situations all through the fossilization processes. Due to the lifelong continuous tooth alternative, most extinct sharks are hence only identified by their nicely-mineralized enamel, which, nevertheless, can deliver deep insights into their evolutionary background.
The teeth of the modern-day tiger shark are one of a kind: they have a broad, double-serrated reducing edge which even permits them to slice as a result of sea turtle shells with ease. Tiger shark tooth are identified in the fossil file because about 56 million yrs. Dependent on these fossil teeth, about 22 extinct tiger shark species have been explained.
An intercontinental staff of scientists led by Julia Türtscher from the University of Vienna has now examined the fossil record of the tiger shark and its extinct family members. With the enable of geometric morphometrics, the experts had been able to show that only 5 of the 22 acknowledged fossil tiger sharks actually depict legitimate species. Nonetheless, tiger sharks have been additional assorted in the earlier and only a solitary species survived until today.
Another intriguing detail in the tiger shark fossil report emerged through this examine. Up to now, it was assumed that the fashionable tiger shark originated ca. 5.3 million a long time in the past. The staff, however, was able to determine quite a few 13.8 million year previous fossil tooth as belonging to this shark demonstrating that it originated substantially earlier than formerly assumed.
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