Your teeth may be hurting because of fish armour that is 500 million years old.

Anyone who has had a cramp in a tooth knows how sensitive our teeth are. This pain is actually useful - it helps you recognize pressure, temperature and other sensations when chewing. However, this sensitivity did not begin in our mouths.

The inner layer of the teeth is known as dentin and turns out to have been developed for a completely different purpose, to help old fish capture the surrounding world.

Teeth began as armor. Her research examined fossils from around 65 million years ago during the Ordovician era. At the time, this tissue was not used to chew. Instead, it helped us to recognize the movement and change of water, the main survival skills in predator-filled environments.

Researchers confirmed that early vertebrate fish with external armor had conferring structures. These were sensory tools, not teeth. They helped fish react to their surroundings, as well as the ways modern animals use skin and antennae.

First Vertebrates

Several fossil teeth from 85 and 50 million years before were also examined. These were considered the earliest examples of vertebrates. However, when scientists compared them to invertebrate shells and armor, such as crabs and shrimp, they saw impressive similarities. It appears that both invertebrates and vertebrates have developed their sensory armor independently.

"If there is such an early animal that swims with armor, it has to feel the world. This is a rather intense, predatory environment, and you will be able to grasp the characteristics of the water around her."

"So, here we see that invertebrates with horseshoe-shaped crab-like armor must also feel the world. In search of the first vertebrate, Yala Khalidi, a postdoctoral researcher at the University of Chicago, began this project in the hopes of finding the oldest known vertebrates.

She asked museums around the country to scan the features of vertebrates, seeking fossils from the age of cameras. The feature she was looking for was the dentin of a small armor known as the Odonto Death.

Many of the rehearsals were small enough to sit on top of a toothpick. To study them in detail, she took her to the Argonne National Laboratory. So the team scanned fossils with high-performance synchrotrons with progressive photon sources all night.

Segmented Confocal Scans Show a segmented confocal scan (green) of tooth-like structures made with aspiration Cowaus Wells fishing, showing a nerve (green) that allows for the transmission of sensory information from the teeth to the nervous system.

"It was a particle accelerator night. It was fun," Haridy said. The fossil called Anatolepis was promising. The scan showed fallopian tubes under his armor, filled with dentin-like material.

At first glance, it looked like a vertebrate. If this had been confirmed, this would have driven the earliest vertebrate records for millions of years. "We celebrated each other high. "Oh, what a god, I've done it at last," said Haridi. It would have been the first tooth-like structure of the Cambrian vertebrate fabric. So we were pretty excited when we saw the dangerous signs of what looked like dentin. "

Anatrepis was a vertebrate who grew up in his aquarium, with the help of sharks and skates, in the incredible structures that grew in his aquarium, Haydy, a barnacle, according to all old and modern animals. It was probably an arthropod.

CT Scanning on the front of the skate shows a stiff, tooth-like dentition on the skin. This indicates that 'teeth' can also be sensory, even if they are not in the mouth. Therefore, these fish have sensitive armor. These arthropods have sensitive armor,” Khalidi inspired.

"This explains the confusion with these early Cambrian animals. People thought this was the earliest vertebrate, but they were an arthropod. This time, we confirmed that a vertebrate called Ellipticius has dentin in a similar structure, and that there is also a confirmed sensory armor in actual vertebrates.

The Origins of Armor, Defense, and Dentals

This study also offers a new perspective on how teeth developed from a type of defensive armor used by the first vertebrates. Today, hair, ice skating, and catfish have a tooth-like skin structure called teeth. When Khalidy examined the catfish, she discovered that these dentists were connected to her nerves like real teeth.

"We believe that these large, armored fish, which had very similar structures, at least very morphologically, have, but in older and modern arthropods, they have soft tissues and help them feel the environment, so they look the same in older and modern arthropods," she said. There are two main theories regarding the origin of teeth. Some say their teeth developed in their mouths and later appeared in their body armor.

Another suggests that they began as external sensory structures and later adapted to teeth. This study supports the second idea. Although they were unable to find early vertebrates, researchers found something important. "For some of these fossils, which are said to be early vertebrates, we showed that they weren't. But that was a bit of a mistake," Shubin said. "We didn't find the earliest, but in a way it cooled a little."