Scales of 450-Million-Year-Old Shark Found in Colorado

A shark without jaws? Scientists say they have found the oldest known trace of a shark--scales from an ancestor so early that it may not have evolved true jaws yet. The finding would set another record if the ancestor actually did have jaws. In that case, the shark scales would also be the oldest known trace of a jawed fish.

Researchers found the scales in a sandstone formation about 30 miles southwest of Colorado Springs. The scales are 450 million years old, about 25 million years older than the previous record for shark remains, they said.

The scales are hollow, teardrop shapes that are found in clusters of up to 10, said researcher Ivan Sansom. Each scale is no more than 0.04 of an inch long, he said.

The scales have internal canals that are characteristic of sharks, Sansom said. Scientists use those canals, rather than fearsome-looking jaws, to classify fish as sharks, he said.

“There’s a reasonably strong possibility they didn’t have jaws” 450 million years ago, said Sansom, a researcher at the University of Birmingham in England.

The findings were reported in the Feb. 15 issue of the journal Nature.