The small, armored fish known as Romundina probably doesn't look like much by today's standards, but when it swam the oceans 415 million years ago, it stood out. Romundina, according to recent research, was one of the first vertebrates to evolve something like a jaw. That evolutionary feature gave way to fully jawed vertebrates, as well as the features such as nostrils — and faces — that we know today on most animals.

Fossils from Romundina were discovered several years ago in the Canadian Arctic. Researchers from Sweden's Uppsala University and other institutions have now examined those fossils, revealing that the fish possessed features halfway between the jawless creatures of its day and the fully jawed vertebrates to come. They then used 3-D imaging to recreate what Romundina's face must have looked like, which you can see in the image above. You can also see the stages of this recreation in the short video below:

The proto-jaw wasn't the only unique part of Romundina's anatomy. It also possessed a short forebrain and something like an upper lip that extended into its single nostril – again, another feature that would become critical in the faces of creatures to come. As jaws further evolved, they pushed this single nostril forward, splitting it into two and creating noses.

"The face is one of the most important and emotionally significant parts of our anatomy, so it is interesting to understand how it came into being," researcher Per Ahlberg of Uppsala University told Reuters.

Almost every vertebrate on Earth today — about 50,000 species — shares similar facial features. The only vertebrates that lack jaws today are lampreys and hagfishes.

The research on Romundina was published this week in the journal Nature.

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