Chinese fish fossils help researchers understand human evolution

According to a series of investigations published in Nature on September 28, 2022, scientists in southern China have uncovered fossil fish dating back more than 400 million years. This graphic, provided by Heming Zhang, portrays Xiushanosteus mirabilis. Photographed by Heming Zhang and released by the Associated Press.

Scientists say that new information provided by 440 million-year-old fish fossils discovered in China is "filling some of the crucial gaps" in understanding how humans evolved from fish.

In 2019, researchers unearthed two fossil fish beds in Guizhou, in southern China, and Chongqing, in the southwest.

The fossils "assist to trace many human body structures back to ancient fishes, some 440 million years ago, and fill some crucial gaps in the evolution of 'from fish to human,'" according to experts from the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology (IVPP).

Fish fossils dating back more than 400 million years have been discovered in southern China, as depicted in this picture by Heming Zhang and published in a series of articles in Nature on September 28, 2022. Photos by Heming Zhang for the Associated Press.

As they put it, their findings "give further solid proof to the evolutionary path," and four publications detailing their research were published in Nature on Wednesday.

Acanthodians, a type of fish found in the Chongqing fossil deposit, are thought to be the origin of all animals with jaws and a backbone, including humans.

In 2013, researchers claimed to have discovered a fish fossil in China that dated back 419 million years, casting doubt on the hypothesis that modern animals with bony skeletons (osteichthyans) originated from shark-like creatures with a cartilage frame.

The scientists concluded that the newly discovered organism, Fanjingshania, lived roughly 15 million years before this ancient fish fossil.

"This is the oldest jawed fish with known anatomy," said Zhu Min, the study's principal researcher.

According to the authors, "the new data allowed us to... acquire much-needed information regarding the evolutionary pathways leading to the origin of crucial vertebrate adaptations like jaws, sensory systems, and paired appendages (limbs)."

Fish fossils dating back more than 400 million years have been discovered in southern China, as seen in this picture by Heming Zhang for the September 2022 issue of Nature. (H. Zhang via AP)

The statement added that the Chongqing fossils are the only ones in the world that date back about 440 million years and "preserves whole, head-to-tail jawed fishes," providing an extremely rare glimpse into a period considered the "birth of fishes."

"It's truly an extraordinary, game-changing combination of fossil findings," said John Long, the former president of the Society of Vertebrate Paleontology and a professor at Australia's Flinders University.

It completely rewrites the textbook on the origins of jawed animals.