Evolution of Ancient Fish Maps Development of Human Face

evolutionSwedish and French researchers used high energy X-rays of a skull to trace the evolution of an ancient fish. Their findings allowed them to map out the development from a single nostril animal to one that resembled the human face, with two nostrils, a larger forehead and the extended length of the face.

The fish under study is the Romundina. It is a 410-million-year-old armored fish. The fish’s skull is from arctic Canada and is part of a Paris collection from the French National History Museum.

The details of the study were published Thursday in the journal Nature. Researchers used X-ray images to trace the evolution transition from jaw-less to jawed vertebrates (animals with a backbone.)

The skull has a combination of ancient and modern characteristics, according to Vincent Dupret of Uppsala University, who was one of the leading authors on the study. They found that the skull had a short front end, resembling a jaw-less vertebrate. The 3D images they took at European Syncrotron revealed a different story however, and allowed them to map out the changes that occurred over time.

They put the fish in sequence with other fossils to create a time-line of sorts that maps out their evolution. The evolving jaw is what actually led to facial development. The early images of Romundina fish features a prominent upper lip, but it did not exactly resemble facial features as they appear in modern times.

Under the category of a placoderm, the Romundina was a small fish that only measured eight inches long and had a toothless jaw. Though the tail end featured a shark-like tail and had flexibility, the nose end was covered in armor.

A single nostril identified the fish at first. As it evolved, however, the right and left nostrils became separated by a second floor under the brain. The forehead did not grow out, but the nose protruded outward between the eyes.

Then the large lip subsided, leaving the nose of the fish as the prominent facial feature. Over time, the forehead grew out, as did the length of the entire face, completing the modern look.

Dupret compares the image of the Romundina to a mirror-image, despite it being millions of years old. He went on to compare it to watching a science fiction movie. The evolution allows people to see themselves in this unlikely ancestor.

The researchers were able to use the X-ray images of the fish’s skull to show how the development of the jaw evolved and gave the fish human-like facial features. Thanks to the technology and being able to digitally reconstruct the images, they were able to place it in an evolutionary lineup among other vertebrate.

The study’s findings are controversial because it adds yet another theory as to how people came in to being. Could human evolution have begun with an ancient fish? The researchers of this study presented how the development of the human face occurred in the Romundina fish over time. Though scientists knew a transition occurred from a jaw-less vertebrate to vertebrates with a jaw, until they studied the fossilized evidence from the skull, they did not know exactly how.

By Tracy Rose

Sources:

Washington Times
Rueters
Eureka Alert

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