Some 160 million years ago, no fish belly was safe from the scourge of blood-sucking vampire fish. Two freakishly large fossil lamprey species have been discovered in China that help explain how these peculiar sea beasts became some of the prime parasitic predators of the Jurrasic oceans.
Lampreys are primitive fish with an eel-like appearance that uses its sucker mouth to latch onto other fish, hence the nickname “vampire fish.” Most species have a complex lifecycle consisting of several stages. They start as blind filter-feeding larvae, often living in the silty beds of freshwater river margins. Eventually, they metamorphose into adult lampreys that bore into the flesh of other fish to suck their blood, acting as a parasite.
There are around 40 species of lampreys living today and they’ve been around for a hell of a long time. The fossil record links them back to an ancient jawless fish ancestor that lived around 450 million years ago, meaning they’ve been on Earth longer than trees.
An illustration of the Jurassic lamprey.
Image Credit: Heming Zhang
However, as only a few lamprey fossils have been discovered, many aspects of their evolutionary history are unclear, such as when they evolved their complex teeth. The two newly described specimens could help to fill in the gaps of knowledge.
Their fossilized remains were discovered in an area known as the Yanliao Biota, an assembly of fossils preserved in northeastern China dating from the Middle to Late Jurassic (174 to 145 million years ago). These particular specimens were found at a layer that suggests they were alive 160 million years ago.
The two new species are unusually large. Yanliaomyzon occisor, measures just over 60 centimeters (23 inches), while the other is slightly smaller and has been named Yanliaomyzon ingensdentes. The researchers noted the new species are around 10 times the length of the earliest known lampreys.
These Jurassic lampreys have the most powerful ‘biting structures’ among known fossil lampreys.
Image credit: Heming Zhang
The fossils feature beautifully preserved oral disks that represent the mouth. Crucially, the shape of these disks provides evidence that the lampreys had already evolved feeding structures that were perfect for chomping, indicating they were predatory by the Jurassic period.
The findings also imply modern lampreys originated in the Southern Hemisphere of the Late Cretaceous, as opposed to the Northern Hemisphere, because the fossils closely resemble the Southern Hemisphere’s pouched lamprey, which foreshadows the flesh-eating habit of modern lampreys.
“Together, fossil lampreys herein suggest that its group is not as conservative as previously thought, and the innovations of their feeding biology had probably underlain their evolutionary increase of the body size and the ‘modernization’ of their life-history mode during the Jurassic period,” the study authors write.
The study is published in Nature Communications.
Dr. Thomas Hughes is a UK-based scientist and science communicator who makes complex topics accessible to readers. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
