Strange ancient animal fossil is the oldest on record, scientists say

A mysterious jellyfish-like ribbed creature is now among the earliest known animals to live on Earth, scientists say.

The Dickinsonia, an animal with an oval body that could grow to more than 4 feet in length, lived 558 million years ago, according to research published Friday in the journal Science. The now-extinct animal probably lived in warm shallow seas possibly alongside other squishy Ediacaran critters, National Geographic reports. 

For more than 75 years, scientists have been fighting over what a Dickinsonia really was, said Australian National University associate professor Jochen Brocks, who was involved in the research. Was it an amoeba or an animal? Evolution gone wrong? Or maybe a plant?

Scientists from Australia, Russia and Germany examined fat molecules in an ancient fossil to come to a remarkable conclusion. 

"The fossil fat now confirms Dickinsonia as the oldest known animal fossil, solving a decades-old mystery that has been the Holy Grail of palaeontology," Brocks said in a statement.

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While the Dickinsonia is now considered among the oldest known animals on Earth, there are other creatures scientists have pegged as older – such as the mollusk-like Kimberella and worm-looking Helminthoidichnites. 

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