Now, recently discovered baby lamprey fossils have overturned that popular evolutionary theory, which some scientists were already starting to question, reports a Canadian-led study published in the latest issue of the journal Nature.

It turns out that baby lampreys from the Paleozoic era, which had been "missing" from the fossil record until now, don't look the way scientists had previously hypothesized — raising new questions about what our ancestors were really like.
Why scientists thought our ancestors were like baby lampreys

To be sure, adult lampreys seem like an unlikely candidate for what the progenitor of vertebrates might have looked like.