Two collections of fish fossils found in China, dating back to around 439 to 436 million years, help researchers make major breakthroughs in studying how humans evolved from fish.

The studies led by Zhu Min, an academician at the Chinese Academy of Sciences (CAS), were published in four papers in the top journal Nature on Wednesday.

One of the fish fossils found and studied by Zhu Min's team. /CMG

The well-preserved fish fossils, dating back to the early Silurian Period, were discovered in southwest China's Chongqing Municipality and Guizhou Province respectively by Zhu's team at the Institute of Vertebrate Paleontology and Paleoanthropology under the CAS over the past decade.

The fossils include five new species of ancient fish, and among them are the oldest-known jawed vertebrates with teeth, which is significant, according to the researchers.

Screenshot of one of the four papers from the website of Nature.

"Without jaws, life would be unimaginable … The origin of jaws may be the most important and profound evolutionary event in the evolution history of vertebrates," the CAS explained in an article published on its WeChat account.

According to Zhu, human body structures, such as eyes, nose, mouth and jaw, can be traced back to fish.

"The new data allowed us to ... gain much needed information about the evolutionary steps leading to the origin of important vertebrate adaptations such as jaws, sensory systems, and paired appendages (limbs)," he said.

The 3D restoration image of the five species of early fish found in the fossils in China. /ScienceApe

From fish to humans

The jawed vertebrates, also known as gnathostomes, are thought to have originated around 450 million years ago, as their emergence and rise is believed to mark a key innovation "from fish to humans."

Many vital organs and body structures of humans could date back to the early evolutionary history of jawed vertebrates, which make up more than 99.8 percent of modern vertebrates including humans.

Previously, the earliest articulated jawed fish fossils identified were only from around 425 million years ago, making it hard to reconstruct the early evolutionary history of jawed vertebrates from around 450 million years ago.

The research team led by Zhu adopted new technologies and methodologies, including high-precision CT scans and big data analysis, presenting to the world for the first time the oldest teeth, head and body from any jawed vertebrate which used to be completely unknown. Such findings are helpful to fill some of the key gaps on how humans evolved from fish. (CGTN)