Scientists now have one more tool that could help them determine how marine ancestors learned to bite thanks to the discovery of fossil fish in southern China. Among the pieces discovered are oldest teeth ever recorded.
These elements constitute a fundamental part for researchers since they contain new clues about a key period of evolutionof which few specimens had been found so far.
In this Wednesday’s issue of the magazine Naturethe researchers provided details about these pieces, including evidence of species never seen before.
Fossils date back to Silurian, a very important geological period in the life of the Earth, which began 443 million years ago and ended 419 million years ago. It is at this time that scientists believe that the vertebrate ancestors – who still swam on a watery planet – they would have begun to acquire jaws and teeth.
Thanks to this, they were able to start hunting prey instead of having to stir the bottom and filter food through the mud. In turn, as explained by the paleontologist at the University of Bristol and author of one of the studies, Philip Donoghuethis brought with it other changes in the anatomy such as different kinds of fins.
Until now, not many fossil finds had been recorded that account for this change, so there were only fragments from that time such as a piece of a spine and a piece of scale, said paleontologist Matt Friedman, from the University of Michigan -who did not participate in this research-.
That is why, as the eyes of researchers around the world rest on these Chinese fossils, it is hoped that the pieces will help fill in some of those blank spaces.
paleontologist min zhu He explained that the discovery of the fossils came in 2019 when a field team returned from a daunting trip in which they had been unsuccessful and decided to explore a clump of rocks on a roadside cliff. When they split it, they found the heads of some fish that seemed to be looking at them.
Once taken to the laboratory, the researchers found a wide range of fossils that, despite being so old, were in excellent condition.
The most common species is a boomerang-shaped minnow that probably used its jaws to scoop up worms, he said. Per Erik Ahlbergof Uppsala University, author of one of the studies.
Another of the fossils corresponds to a creature similar to a shark but with bony armor on its forehead, an unusual combination. A well-preserved jawless fish offers clues about how fins evolved into arms and legs. However, although the heads of these fossils are abundant, in this case the entire body appeared.
On the other hand, the researchers found teeth, bones called tooth spirals with numerous pieces implanted in them. Are 14 million years older than others found of any other species and the oldest concrete evidence of jaws to date, Zhu said.
Australia’s Flinders University biologist Alice Clement, who was not involved in the research, said the find is “remarkable” and could completely change what is known about the period.
The wide range of fossils indicates that there were abundant toothed creatures in the waters at the time, Clement added, although the “age of the fish” corresponds to the next era of evolution.
(With information from AP)
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