The rich story of how jawed vertebrates spread to all corners of the globe has long been missing the first few pages—until now
—tiny semicircular arcs of pointy teeth, barely a few millimeters across.
But until these new discoveries, complete skeletons of the earliest jawed vertebrates hadn’t been found in rocks more than 425 million years old. In recent years, paleontologists have found scales and other bits that suggest the presence of jawed fish during the Silurian period, which lasted from 443.8 million to 419.2 million years ago. But without complete skeletons to refer to, researchers could infer little about these early jawed vertebrates’ lives and anatomies.
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