Lamprey Larva Fossils Shed Light on Human Biology

In the spirit of Oct. 15, National Fossil Day, a new study has come out describing the earliest-known lamprey larva fossils, recently discovered in Inner Mongolia. While few people take the time to explore the ancient origins of these eel-like creatures, their evolutionary saga in fact helps shed light on humans' biological roots.

These lamprey larvae data back to the Lower Cretaceous period - at least 125 million years ago - and are the first fossils found that display stages of pre-metamorphosis and metamorphosis. The evolutionary history of these bloodsuckers, in turn, helps scientists better understand how humans came to be what they are today.

According to Desui Miao of the University of Kansas (KU), a study co-author, some features of the human body come from jawless fish, such as the lamprey.

"For example, a jawless fish such as a lamprey has seven pairs of gill arches, and the anterior pair of these gill arches evolved into our upper and lower jaws," he said in a statement. "Our middle ear bones? They come from the same pair of gill arches."

Lamprey, a typically parasitic organism, doesn't just shed light on human biology, but on the development of all animals with a backbone. This makes them extremely fascinating to scientists who wish to learn more about their three-phased life cycle. But lampreys are small and soft, thus seldom fossilized. Fortunately for the researchers, during the lush Lower Cretaceous era, freshwater lakes covered Inner Mongolia, creating for beautifully preserved lamprey fossils.

"This type of rock preserves very fine details of fossils," Miao added. "The same rock preserved evidence of dinosaur feathers from this era."

According to the KU researcher and colleagues, today's lamprey don't look much different from those living some 125 million years ago or more.

"The developmental stage is almost identical to today's lamprey. Before this, we didn't know how long lampreys have developed via metamorphosis. Now, we know it goes back 125 million years at least," Miao said.

Fossils can tell scientists a lot about ancient organisms and how they relate to those alive today. They also provide clues to past climates, and how animals, plants, and ecosystems responded to changes, according to the National Park Service, which could prove beneficial considering the world is the middle of climate change.

"When conditions change outside of their comfort zone, animals or plants must migrate to more favorable conditions, adapt to the changes, or they will not survive," the website wrote. "Fossils record these responses. They also provide clues for changes happening now and in the near future."

So fossils, like the lamprey fossils found, are windows not just into the past but into the future as well.

The new findings were published in the journal Proceedings of the National Academy of Sciences.