Paleontologists in China have unearthed the 160-million-year-old fossilized remains of two new lamprey species. Their discovery—published Tuesday in the journal Nature Communications—helps fill a gap in the fossil record and offers insights into how these eerie, predatory creatures evolved.
Lampreys are jawless fish that look similar to eels. They go through an unusual life cycle that involves three distinct stages and a metamorphosis, like how a caterpillar transforms into a butterfly. Many species, grouped together as parasitic lampreys, have perfected a sinister feeding strategy: Using their disc-shaped mouths and sharp teeth, they latch onto prey and suck out its blood.
But based on the look of the fossilized teeth and mouths, scientists think these newfound prehistoric lampreys weren’t simply sucking blood—rather, they were gouging out flesh from their prey “like living ice cream scoops,” as Riley Black writes for National Geographic. One of the fossils still had bone fragments in its stomach, meaning its bite was powerful enough to chomp through its prey’s skeleton.
“Living lampreys are always hailed as ‘water vampires,’ but their ancestor might be a flesh eater, their teeth tell,” says study co-author Feixiang Wu, a paleontologist at the Chinese Academy of Sciences, to Popular Science’s Laura Baisas.
Researchers discovered the pair of new species in a fossil bed in North China. The bigger of the two measures about 23 inches long, making it the largest fossilized lamprey ever discovered. Paleontologists named it Yanliaomyzon occisor, with “occisor” meaning “killer” in Latin. They termed the smaller species, which measures roughly 11 inches long, Yanliaomyzon ingensdentes, a name derived from the Latin words for “large teeth.”
The well-preserved fossils were in such good shape that paleontologists could make out the creatures’ biting structures and oral discs.
“There have been no other lamprey fossils from the dinosaur age that preserve their terrorizing oral apparatus quite so clearly,” says Tetsuto Miyashita, a paleobiologist at the Canadian Museum of Nature who was not involved in the new research, to Nature News’ Xiaoying You.
For example, the oldest fossilized lamprey remains date to around 360 million years ago, during the Paleozoic. They reveal that early lampreys were much smaller—around an inch or so long—with weakly developed feeding structures that indicate they did not suck blood or eat flesh. These early lampreys also didn’t go through metamorphosis. Modern lampreys, by contrast, are large, have complex teeth and experience all three life stages.
But since very few lamprey fossils exist, paleontologists don’t know much about how the creatures evolved between those two periods. The new fossils help add to that murky picture and suggest that, by the Jurassic period, lampreys had already evolved their predatory feeding structures and larger body size. Paleontologists don’t know for sure, but they suspect lampreys had also evolved their three-phase life cycle by this point, too.
The recently unearthed fossils also indicate today’s lampreys may have originated in the Southern Hemisphere during the Late Cretaceous period, which spanned 100.5 million to 66 million years ago.