Human jaws evolved from ancient fish

Prehistoric fish fossils found in China include bones that bear the jaw characteristics of modern vertebrates.

Ancient fish fossils with features of modern vertebrate jaws. Photo: Dinghua Yang.

Scientists published the results of a study on a prehistoric fish fossil, Qilinyu, about 30 cm long, appearing 423 million years ago, excavated in Yunnan province, China in the journal Science recently. This fish species has bones similar to the jaws of modern vertebrates, including humans, according to Reuters.

Fish appeared more than 500 million years ago, the first vertebrates in the world. However, in primitive times, they did not have jaws. Placoderms were the first vertebrates to have jaws, an important evolutionary step that helped them capture prey. They had heads and most of their bodies covered in armor, and their jaws had bony blades that acted like teeth to tear and crush prey.

Qilinyu is a placoderm but has three bony parts, including the lower jaw, upper jaw and premaxilla, a feature of modern vertebrate jaws.

"In humans, the lower jaw is made up entirely of the mandible. Most of the upper jaw is made up of the maxilla, but the incisors are remnants of the premaxilla," explains Per Ahlberg, a paleontologist at Uppsala University in Sweden.

This finding contradicts the previous view that modern jaws evolved later, appearing in the early stages of bony fish. "We now know that a genus of placoderms evolved into modern vertebrates and jaws," Ahlberg said.

According to VNE