Rare fossil that looked like a balloon has been discovered

Last updated at 11:57
A picture of the fossil, called 'Nidelric pugio'© Prof Derek J Siveter of Oxford University

An ancient fossil thought to be 520 million years old, could tell us more about what life was like in Earth's ancient seas.

The fossil, called Nidelric pugio was discovered in Chengjiang, in southern China and is around 9 cm long.

The researchers who found it say that when it was alive, it would have looked like a balloon covered in an outer skeleton made up of spines.

This is the only fossil of this animal, making it incredibly rare.

To enjoy the CBBC Newsround website at its best you will need to have JavaScript turned on.
Dr Sarah Gabbott, from the University of Leicester, tells us more about the discovery

The fossil looks a bit like a squashed bird's nest because during fossilisation the skeleton was squashed by lots of layers of rock.

The research into the fossil was led by an expert at Yunnan University in China, with help from palaeontologists at the Universities of Oxford and Leicester in the UK.

Their report was published in the journal Scientific Reports.