Flesh-Eating Lamprey Species Discovered in Fossil Record

The Yanliao Biota, located in North China, is home to a plethora of well-preserved fossils believed to be 160-million-years-old. Among these fossils, paleontologists recently discovered two fascinatingly large species of ancient lamprey. Rather than being characterised by fur and feathers like dinosaurs, pterosaurs and early mammals, these lampreys were carnivorous creatures that attacked and bore holes into their nearby victims.

In contrast to modern parasitic lampreys with funnel-shaped mouths for flesh or blood consumption, the newly found species -- as per their teeth and feeding apparatuses -- were carnivorous rather than hematophagous, as outlined in a report published on October 31 in Nature Communications.

According to Feixang Wu, a paleontologist from the Chinese Academy of Sciences in Beijing, and his colleagues, these fossils represent the oldest lamprey specimens that definitively demonstrate a preference in feeding mode. The fossilized tooth arrangements of both these ancient species are strikingly similar to a present-day Southern Hemisphere species of lamprey, famous for its flesh-eating tendencies.

The larger of the two species – the Yanliaomyzon occisor, which translates to "killer" in Latin – was approximately the size of a small dog, measuring 64 centimeters in length. By contrast, Y. ingensdentes, the name of its smaller counterpart meaning "large teeth" in Latin, was less sizeable. In comparison, the length of a modern adult lamprey ranges from about 15 to 120 centimeters.

Bearing in mind that lampreys -- a lineage of jawless vertebrates -- have existed for roughly 360 million years and that they infrequently fossilize well, there is no surprise that there are substantial gaps in their evolutionary record, raising questions about their ecology and their feeding styles' evolution.

The earliest lampreys did not exhibit the same characteristics as their successors. They were diminutive, measuring only a few centimeters in length, and lacked similar powerful teeth. In addition, their life cycle differed from modern lampreys' as they lacked a life cycle consisting of a filter-feeding larval stage, a juvenile parasitic stage, and an adult spawning stage.

What these newfound fossils suggest is that by the Jurassic Period, lampreys had morphed into formidable predators, characterized by greater body sizes and complex feeding structures.

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