Researchers have discovered the earliest known ancestor of humans – along with a vast range of other species.
They say that fossilised traces of the microscopic 540-million-year-old creature are exquisitely well preserved. The sea animal is the earliest known step on the evolutionary path that led to fish and – eventually – to humans.
Saccorhytus was about a millimetre in size, and is thought to have lived between grains of sand on the sea bed.
Its most striking feature is its large mouth, relative to the rest of its body.
According to the scientists, Saccorhytus is the most primitive example of a category of animals called “deuterostomes” which are common ancestors of a broad range of species, including vertebrates (backboned animals).
Scientists say that as an early deuterostome this samll fossils may represent the primitive beginnings of a very diverse range of species, including ourselves. All deuterostomes had a common ancestor, and that is what we are looking at here.
Saccorhytus now gives us remarkable insights into the very first stages of the evolution of a group that led to the fish, and ultimately, to us.
Until now, the deuterostome groups discovered were from between 510 to 520 million years ago. These had already begun to diversify into not just the vertebrates, the group to which we and our ancestors belong and animals such as starfish and sea urchins.
Because they looked so different from one another, it was difficult for the scientists to determine what an earlier, common ancestor might have looked like.
Details of the discovery appeared in Nature journal.