The first tooth are organs of the skin of the ancient fish

Teeth first improved as sensory organs, not for chewing, according to a new animal analysis Fossils. The first like tooth-like structures seem to be sensitive nodules of the skin of the first fish to find changes in the surrounding water.

Search supports a long-term idea that teeth first progress outside the mouth, saying Parents of children on University of Chicago.

While there are some evidence that it is back to it, there is an obvious question. “What is good to have all these outdoor teeth?” Haridy says. One possibility is that they serve as a defense armor, but the Heary thinks there is more. “It’s great to hide yourself with tough things, but what if tough things can help you understand your environment?”

True teeth see only backboned vertebrates, such as fish and mammals. Some invertebrates have structures such as teeth, but bottom tissues are perfectly different. It means teeth come from evolution of first vertebrates: fish.

Haridy and his team re-examined fossils claimed to be the oldest examples of fish teeth, using a synchrotron to scan it before ever.

It focuses primarily with fragmented fossils of animals called AnatolepisWhich date is from the late part of the Cambrian period, which runs from 539 million to 487 million years ago, which runs from 487 million to 443 million years ago. These animals have a hard exoskeleton, combined with tubules.

These dentine tubules are translated, one of the hard tissues that make up teeth. In human teeth, Dentine is the yellow layer under the hard white enamel and it makes many tasks, including sensing pressure, temperature and pain.

It is agreeable to tubules who are teeth in the tubes called odontalogs and that Anatolepis an early fish.

That’s not what he found Haridy and his team. “We see that the internal anatomy (in tubules) never look like a vertebrate,” he said. After examining structures from a variety of animals, they know tubules are the most similar to parts called sensilla found by the exproseons of insects and spiders. It’s like pegs or small hairs and found different events. “It can be all from the taste of vibrating the changes in air currents,” as Haridy.

This means Anatolepis An arthropod, not a fish, and its tubules are not the direct teeth.

“Dentine is likely to be an innovation, however the sensory capabilities in a hardened exterior face are in the first invertebrates,” as Gareth Fraser on University of Florida In Gainesville, not included in the study.

with Anatolepis from the picture, the team says, the oldest known teeth are the Epettychiusto know only from the ordovician period. It has real dentine – to odtantodes in their skin.

Haridy says invertebrates like Anatolepis and early vertebrates such as Epettychius independently improved difficult, sensory nodule in their skin. “These two different animals need to feel their way through the muck in the ancient seas,” he said. In accordance with this, the team knows that the odontanes of some modern fish have nerves – suggests a function of sensory.

Once some fish turn into active predators, they need a way to keep their victim, so hard odtantodes make their way to the mouth, where they can get to bite.

“On the basis of available data, teeth-like structures are likely to lead the skin of early vertebrates, before the oral invasion of these structures that have become teeth,” Fraser said.