TAC at the front of a lane, showing the hard and teeth -like denticles (the orange) on your skin
The teeth are good for chewing and biting, but they are also sensitive – and this may have been precisely their original function, 460 years ago, in the skin of old fish.
A study this Wednesday in Nature revealed that the teeth evolved from fish skin.
According to the new analysis of animal fossils, the teeth evolved initially as sensory organs and not to chew.
These first, teeth -like structures seem to have been sensitive nodules (from which teeth sensitivity) capable of detecting changes in surrounding water.
“The discovery supports a longtime idea that the teeth evolved first from the mouth,” said the corresponding author of the study, Kids Haridyfrom the University of Chicago (USA), quoted by.
Although there are already some evidence that supported this idea, there was still a fundamental obvious in the air: What is it for all these teeth abroad?
One possibility was that they serve as defensive armor, but the new study theorizes that there is more than that.
“Teeth” have been around 460 million years ago
The researchers re -examined fossils that claimed to be the oldest examples of fish teeth.
Began by focusing on fragmentary fossils of called animals Anatolepisdating from the last part of the Cambrian period (between 539 million and 487 million years ago) and the beginning of the ordovic period (between 487 million and 443 million years ago).
These animals had a hard exoskeleton, dotted with tubules, which had been interpreted as being Dentin tubules – One of the hard tissues that constitute the teeth.
As New Scientist explains, in human teeth, dentin is the yellow layer under the hard and hard enamel. Performs many important functions, including Pressure, temperature and pain detection.
This led to the idea that Tubules are precursors of teeth so -called odontodes and that the Anatolepis It is a primitive fish. However, the new study theorizes that, after all, Anatolepis It is an arthropodnot a fish.
There are doubts. But the main conclusion of this new study is that both invertebrates and Anatolepis and primitive vertebrates as Eriptychius will have independently developed, hard and sensory nodules on the skin.
“These two very different animals needed to feel their way through the mud of the old seas,” details this point in common, which can explain the Common but independent evolution.
In line, the team found that these “teeth” in the skin of some modern fish still have nerves – which suggests that the sensory function remains present.
