Fish With First Face Found: Jaw-Dropping Fish Fossil Suggests Skeleton Evolved Face First

A newly discovered fish fossil may have the first face.

The ancient, newly-discovered fish may be the earliest-known creature with a recognizable face.

The fish lived 419 million years ago in the Late Silurian seas of China.

The finding links two groups of fishes thought to be unrelated, and challenges notions of how faces evolved in vertebrates.

The fish, entelognathus primordialis (meaning "primordial complete jaw"), is the oldest known animal to have face-forming jaw and cheek bones similar to those of today's bony fishes and most terrestrial animals, including human beings.

"Entelognathus had a rather unprepossessing face," co-author Per Erik Ahlberg of Uppsala University said. "The mouth was wide, the forehead low and flat, and the small, close-set and almost immobile eyes pointed forwards like a pair of car headlights."

Almost all vertebrates with belong to a group known as gnathostomes, or jawed vertebrates. At some point, the gnathostomes branched into cartilaginous fish (like sharks and rays) and bony fish and four-limbed animals (including humans and many other mammals).

Scientists have long thought that the common ancestor of gnathostomes was more similar to cartilaginous fish. They thought it "would have looked something like a shark, devoid of armor and with a largely cartilaginous skull," according to study leader Min Zhu.

However, on investigating a Entelognathus fossil found in a seabed in China, they found that the fish had a jaw-but no teeth. The fish also had tiny eyes set inside large "bony goggles", a heavily armored head, and a scaly tail.

All known bony fishes had teeth...but this one simply didn't. The fossil adds to the mystery of how teeth originated, Young said.

At first, Entelognathusappears  looks like a normal placoderm, an extinct type of heavily armored fish that, until now, invariably had simple jaws and cheeks.

"But the original fossil of Entelognathus proved to be something far more bizarre and significant," Zhu said.

However, upon looking closer, researchers realized that the fish had a  much more complex arrangement of smaller bones: a mandible on its lower jaw, a premaxilla and maxilla on its upper jaw, and even cheekbones. These types of bones are more complex-and are characteristic of bony fish and land animals, including humans. This means that this weird-looking fish is the most most ancient animal with what humans would recognize as a face, Live Science reports.

"This is certainly an amazing discovery, both because of its age [Silurian] and the morphology of the lower jaw," Gavin Young, a zoologist at Australian National University in Canberra, said