Gigantic ‘water vampire’ fossils found in northern China

But researchers working at the Yanliao Biota – a major depository of Jurassic-era fossils on the borders of modern-day Inner Mongolia, Hebei and Liaoning provinces – have now uncovered two 160 million-year-old lampreys that have helped them fill in the gaps.

Researchers from China and France analysed the fossils – the largest of which was over 60cm (24 inches) long – and found that lampreys had already become predatory by the Jurassic period, when dinosaurs roamed the Earth, and had evolved enhanced feeding structures.

The fossils indicate that they were capable of eating flesh and could grow more than 10 times longer than the earliest lampreys.

“The innovations of their feeding biology had probably underlain their evolutionary increase of the body size and the ‘modernisation’ of their life-history mode during the Jurassic period,” the team from China’s Institute of Vertebrate Paleontology and Paleoanthropology and the French National Museum of Natural History wrote in an article published in the peer-reviewed journal Nature Communications on Wednesday.

Wu added that the new fossils had allowed the researchers to recreate how the ancestors of today’s lampreys lived as well as their biological characteristics and evolution.

“The living fossils might seem to have remained unchanged in the past 360 million years, but now we know that they developed a three-staged life cycle, like a tadpole developing from an egg to a frog, as they evolved,” he said.

The team also found that the fish had evolved a complex structure of teeth to hold on to their prey and bite and were able to take in sufficient energy to embark on the three-stage cycle by the era in question.

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Modern day lampreys are sometimes seen as a threat to other fish, with previous studies finding they can kill around 40 to 60 per cent of those they attack.

But Wu said they also play an important role in the ecosystem transporting marine-derived nutrients when they migrate up rivers from the sea to spawn. He also said studying them could help medical research because they have immune system cells that are similar to the white blood cells that fight infections in humans.