520-Million-Year-Old Larva Fossil Reveals Well-Preserved Brain

Imagine examining a 520-million-year-old larva with its brain, internal organs, soft tissues, and nervous system still intact. This remarkable discovery was made by scientists from Britain’s Natural History Museum, who uncovered an exceptionally well-preserved fossil in China.

This ancient larva lived during the Cambrian period, a time known for a rapid diversification of life on Earth. Fossils from this era are crucial for understanding the evolution of life on our planet.

The larva belongs to the species Youti Yuanshi, a prehistoric arthropod with modern relatives that include insects, centipedes, and crabs. Youti is believed to have inhabited the ocean floor during the Cambrian period.

The fossil, found in China’s Yu’anshan Formation, measures just four millimeters long, smaller than a grain of rice. Detailed internal structures were revealed through X-ray computed tomography.

According to the Natural History Museum, the larva had tiny legs, a highly developed head, a complex brain, and a digestive tract. Emma Long, co-lead author of the study published in Nature journal, highlighted that the larva’s organ systems are preserved in 3D, offering a remarkable comparison to the carbonaceous compression fossils found in Canada’s Burgess Shale.

“Youti provides a framework for interpreting these flattened fossils, enabling us to better understand the complex organ systems of these early animals,” Long said.