Photo: Miguel Riopa/AFP (Getty Images) Derpy from the side and hellish from below, the lamprey is the bane of the Great Lakes fisheries industry. A jawless, bloodsucking fish, the lamprey is often considered an ancestral early vertebrate for its rudimentary morphology and its larval life stage. Now, a team of researchers has authored a new study about fossilized lamprey larvae from the Devonian Period that they say shows lamprey evolution occurred differently than previously thought. This would mean we’d need to change our vertebrate origin story. Advertisement The researchers’ paper was published on Wednesday in the journal Nature. Their argument hinges on the lamprey life cycle. Modern lamprey larvae, called ammocoetes, are blind filter-feeders, which later transform into their noodly, predatory adult selves. Biologists and paleontologists alike have seen that ammocoete larval stage as a relic of early vertebrate evolution, and a sign that lamprey could be relied on as a living fossil that helps explain where all backboned animals came from. But the recent team describe baby lamprey fossils that are not ammocoetes—these fossils look just like smaller versions of adult lampreys—suggest that that larval stage was a later evolutionary adaptation, one unique to lampreys.