The oldest animal skeleton ever found was discovered in South Australia.
The organism, called Coronacollina acula, was found by a team from the University of California. They confirmed that it is 560 million years old.
The finding provides insight into the evolution of life on the planet, why animals go extinct, and how organisms respond to environmental changes.
The discovery also can help scientists recognize life elsewhere in the universe. Coronacollina acula lived on the seafloor. It was shaped like a thimble with at least four 20 to 40-centimetre-long spikes called ’spicules’ attached. These probably held the creature up.
The researchers believe it ingested food in the same manner a sponge does, and that it was incapable of moving around. How it reproduced remains a mystery.
“Up until the Cambrian, it was understood that animals were soft bodied and had no hard parts,’ said Mary Droser, lead researcher and a professor of geology at the University of California.
“But we now have an organism with individual skeletal body parts that appears before the Cambrian. It is therefore the oldest animal with hard parts, and it has a number of them – they would have been structural supports – essentially holding it up. This is a major innovation for animals.”
Some researchers were so mesmerized by the find that they couldn’t look away. David Attenborough was in this position for over three days, before being pried away.
Coronacollina acula is seen in the fossils as a depression measuring a few millimetres to two centimetres deep. But because rocks compact over time, the organism could have been bigger – three to five centimetres tall. Notably, it is constructed in the same way that Cambrian sponges were constructed.
“It therefore provides a link between the two time intervals,’ Droser said. ‘We’re calling it the “harbinger of Cambrian constructional morphology”, which is to say it’s a precursor of organisms seen in the Cambrian. This is tremendously exciting because it is the first appearance of one of the major novelties of animal evolution.”
This is what it probably looked like alive:
According to Droser, the appearance of Coronacollina acula signals that the initiation of skeletons was not as sudden in the Cambrian as was thought, and that Ediacaran animals like it are part of the evolutionary lineage of animals as we know them.
“The fate of the earliest Ediacaran animals has been a subject of debate, with many suggesting that they all went extinct just before the Cambrian,’ she said. ‘Our discovery shows that they did not.”
Results of the study appeared online recently in Geology.