Researchers found two lampreys that lived about 160 million years ago in Jurassic seas in northern China. “Well-preserved remains” show that these jawless fish had already reached a large size at that time and had adapted to predatory behavior.

Although lampreys have existed for at least 360 million years, they have left little trace in the fossil record: Their cartilaginous skeletons and keratinized teeth are poorly preserved. Previously, paleontologists had discovered only seven fossil lamprey species, five of which lived during the Paleozoic period, 550-250 million years ago.

Researchers examining the fossil remains of two fish found in China found that the teeth of Jurassic lampreys were radically different from those of their Paleozoic ancestors. Earlier lampreys had very small and simple teeth and survived by scraping organisms from the hard surface of the bodies of other aquatic animals.

But by the Jurassic period, at least some lampreys had become predators, devouring the flesh of their prey. They had a powerful bite mechanism and were larger than their ancient relatives; The size of a find from the Jurassic period is approximately 60 cm; this is almost 6 times the size of Paleozoic jawless fish. This shift probably led to the emergence of thin-layer mining.

Scientists believe that a change in diet and metamorphosis may be related. The larval diet of algae prevents lampreys from growing too large or fast, and the first animals may not survive without food during regeneration. But as soon as adult lampreys adapted to eating meat, they were able to produce strong offspring that could survive the barren period of metamorphosis.

Modern lampreys are one of two extant lineages of a once diverse group of jawless fish. These fish have an unusual life cycle in which they begin as blind, toothless larvae that feed on microscopic algae and detritus. As they grow, they develop into an adult form with a suction cup-like mouth with ring-shaped sharp teeth. Some modern species of stonefish are sometimes called “vampire fish” because they suck the blood of their prey. Source