Over a year ago, the prehistoric remains of several ‘sea monsters’ were unearthed in Northern China, a discovery that has sparked a wave of excitement and underscored the profound significance of paleontology in the archaeological world.

In 2023, paleontologists working at a site in Yanliao Biota, northern China, stumbled across several new lamprey fossils, which they named Yanliaomyzon occisor.

Lampreys are thought to have emerged in the ocean around 360 million years ago. Modern descendants of the species can reach up to a meter in length.

One of the fossilized lamprey unearthed in China measured an impressive 64 centimeters, marking a significant increase in size.

The jawless eel-like fish, sometimes called “water vampires” for their habit of attaching to prey and sucking their blood through toothed funnel-like mouths, provides scientists with a clearer view of a creature’s evolution.

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—are filling in the gaps with an ancient fossil.

A team of researchers studied the fossils under the guidance of Feixiang Wu of the Chinese Academy of Sciences.

Wu, along with his colleagues, including Chi Zhang of the Chinese Academy of Sciences and Philippe Janvier of the National Museum of Natural History in France, meticulously studied fossils, which allowed them to gain insight into the examples.

Lampreys, alongside hagfish, are two species that comprise the living jawless vertebrate groups.

According to the researchers, the study of Lampreys is pivotal in understanding the evolution of vertebrates.

Despite the recent discovery, the evolution of Lampreys is still somewhat mysterious, as few fossils have been found worldwide.

By the Jurassic era, lampreys had evolved into aggressive predators with much larger bodies than their Paleozoic relatives. The researchers note these fish had the strongest “biting structures” of any lamprey species.

Researchers observed skeletal remnants within the lamprey’s digestive tract during the study, including skulls, jawbones, and teeth.

The team from China’s Institute of Vertebrate and Paleontology and Paleoanthropology and the French National Museum of Natural History detailed their findings in an article published in the peer-reviewed journal Nature Communications.

The Great Dying is a period in Earth’s history when something unknown wiped out most life on the planet. Most researchers look to fossils of animals that date back to the era to find patterns, hoping to piece together the greatest natural tragedy on this Earth.

“The lamprey is a terrific animal,” lead author Wu Feixiang, a paleontologist and professor at the institute, said.

The earliest of the animals that coexisted with the larger fish were covered in thick body armor that the tiny lampreys wouldn’t be able to penetrate with their teeth.

From the observations made during this study, the researchers were able to discern a drastic change in feeding structures and habits throughout the long evolution of the lampreys. They even theorized an alternative origin for the fish species.

Wu added that the fossils have allowed the team to recreate how ancestors of today’s lampreys lived, 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.

It also seems that lampreys kept their vicious behavior throughout time, giving these fish the ability to dominate their prey that share the water with them.

Lampreys play an important role in their ecosystem. They drive marine-derived nutrients when they migrate up rivers from the sea to lay their offspring.

“There have been no other lamprey fossils from the dinosaur age that preserve their terrorizing oral apparatus quite so clearly,” says Canadian Museum of Nature paleontologist Tetsuto Miyashita, who was not involved in the new study.

There are not many known prehistoric lampreys that provide as much detail and information as the ones discovered in Liaoning Province. “The lamprey fossil record is very sparse and poor,” Miyashita says