A new study has found that humans have a prehistoric fish to thank for the enamel on their teeth, as the protective tissue was first formed on the scales of the long dead Psarolepis Romeri and Andreolepis Hedei.
• The benefits of enamel and the species know to sport the protective tissue.
• Details on the link between enamel and ancient fish.
A team of researchers came to this conclusion after looking at the fossils of several extinct species of fish, as well as at the DNA of several modern day animals.
Enamel is believed to be the hardest tissue found in the human body. It’s made almost entirely out of minerals such as calcium and phosphorus. It serves as a protective force for our teeth when we chew food, and prevents us from feeling pain when consuming something that’s either really cold, or really hot.
But human beings aren’t the only species to enjoy the benefits of enamel. The issue has been found a wide range of animals – from four-limbed mammals, to birds, to reptiles, to amphibians. And now the scientific community is adding lobe-finned fish to the list.
This is a remarkable finding and an invaluable source of information for researchers as some of this ancient lobe-finned fish evolved to walk on land and live outside their original aquatic environment. But the evolution did not occur without major transformations.
It turns out that certain species of prehistoric fish had enamel-like tissue covering their entire bodies, on the exterior, almost acting like an amour. But some of them also had the protective tissue on some parts of their teeth. The research team informs that the genes responsible for making all of these protective tissues are pretty much the same.
Once the field experts noticed this, they compared the outer skeletons and teeth of several groups of fish, and discovered that the enamel first formed on the scales of fish with skeletons made of bone – Psarolepis Romeri.
The species intrigued the researchers it’s one of the oldest known species to sport enamel. The Psarolepis Romeri used to live in present day China, about 420 million to 445 million years ago.
But despite the fact that the species is the first to enjoy the benefits of enamel, it did not have any protective tissue on its teeth. This assessment caused the field experts to take a closer look at another species of prehistoric fish that lived around the same time that the Psarolepis Romeri did – Andreolepis Hedei.
Andreolepis Hedei have also caused many debates in the scientific community due to the presence of the exact same characteristics – enamel can be found on their scales, but not on their teeth.
Some researchers are now saying that the dead Psarolepis Romeri and Andreolepis Hedei may be the same species.
But either way, the study authors say that “enamel originated on the scales, before colonizing the dermal bones and finally the teeth”.
The findings were published earlier this week, on Wednesday (September 23, 2015), in the journal Nature.
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