Researchers Find Fish Fossil that Might Explain Evolution of Facial Features

Researchers have discovered a fish fossil that has facial features similar to a modern fish. The newly found fossil might be the missing link between ancient and modern fish and may show how vertebrates, including humans, evolved facial features.

The ancient fish, called Entelognathus primordialis, lived about 419 million years ago. It had a complex face made of many bony plates, just like the ones found in humans and other vertebrates. However, records show that other fish living at that time had no facial complexity.

Scientists had earlier thought that the ancestor of jawed vertebrates or gnathostomes must have looked something like a shark with a cartilaginous skull. Understanding evolution of gnathostomes and their ancestors is important. The gnathostomes split into two branches; one sprouted into cartilaginous fish (sharks and rays) and the other evolved into bony fish and eventually humans, NBC reported.

The discovery of the fish fossil challenges how researchers explained the evolution of the face. According to researchers who worked on the study, there is a strong possibility that faces of modern bony fish might have evolved from the ancestors of E. primordialis. If our facial features evolved from E. primordialis, then researchers might have to re-write the evolutionary tree of vertebrates, Nature reported.

"This is like finding the nose of a space shuttle in a hay wagon from the Middle Ages," paleontologist Xiaobo Yu of Kean University in New Jersey, one of the researchers responsible for the new find, told USA Today via e-mail.

The fish that evolved first facial features

Entelognathus primordialis lived during the end of Silurian period, right before the Devonian- also known as The Age of Fishes, The Los Angeles Times reported.

The fish isn't very pretty to look at; it has tiny eyes set in large eye-sockets. Also, the fish didn't have any teeth.  According to researchers, science is still clueless about how teeth originated.

When researchers found the fossil, they thought it belonged to placoderm- an extinct fish believed to have a heavy armor. However, closer inspection showed that the fossil wasn't of a placoderm as it had a distinctive cheek-bone, upper and lower jaw, Livescience reported. The fossil was found near Qujing, in Yunnan, southern China.

The study also shows that placoderms and bony fish were related. Until now, researchers had believed that bony fish had developed their facial features independently.

The study is published in the journal Nature.