A group of international scientists in China have discovered what they say is the oldest known ancestor of humanity.
The 540-million-year-old fossil is a microscopic sea animal, no larger than a millimetre in size, called a Saccorhytus. It was discovered in central China.
The team of researchers from China, the UK and Germany say the animal is part of the deuterostomes family, which are common ancestors of a broad range of species, including vertebrates, and therefore humans.
“The detail was jaw-dropping”
Degan Shu of Northwest University in Xi’An, where the fossils were discovered, said that the Saccorhytus “gives us remarkable insights into the very first stages of the evolution of a group that led to the fish, and ultimately, to us”.
The fossils are so small that Professor Simon Conway Morris of the University of Cambridge, who was also part of the team, told BBC news: “to the naked eye, the fossils… look like tiny black grains, but under the microscope the level of detail was jaw-dropping”.
Scientists have determined that the Saccorhytus was covered with flexible skin and muscles, and therefore moved by wiggling between grains of sand on the sea bed.
But the team in Xi’An noted that the most fascinating feature of this ancient creature is its mouth, which is relatively large compared to the rest of its body. It is understood that it ate by collecting food particles or even other minuscule creatures. The lack of an anus suggests the Saccorhytus excreted waste through the same orifice which it consumed food.
The group of scientists also point to structures on its body which may have allowed water to escape, and may therefore be an early iteration of gills seen on fish today.