Beijing, Dec 10 (IANS): An international team has discovered a rare 520 million years old animal fossil in China that provides an unprecedented view of life in the earth's ancient seas.

Shaped like a "squashed bird's nest", the fossil classified as "Nidelric pugio" was found at Chengjiang in southern China.

It is probably a "chancelloriid" - a group of bizarre, balloon-shaped animals with an outer skeleton of defensive spines.

The animal was flattened during the fossilisation process so that it looks like a squashed bird's nest.

"There is only one fossil of this enigmatic animal after 30 years of collecting by our Chinese colleagues at Chengjiang. It is exceptionally rare but it shows us just how strange and varied the shapes of early animals could be," said study co-author Tom Harvey from University of Leicester.

The team has named the species "Nidelric pugio" to honour the late professor Richard Aldridge, an internationally-renowned apaleontologist and ornithologist from University of Leicester.

The name of the fossil is derived from Latin word Nidus which means "bird's nest" and adelric, derived from the Old English personal name "Aedelic" - "adel" means "noble" and "ric" is "a ruler" - which also means Aldridge in English.

In southern China, ancient rocks in Chengjiang county, Yunnan province yield a diverse array of fossils preserved with traces of their soft anatomy, including their legs, eyes, guts and even brains.

Amongst the fossils are many animals which can be related to modern forms, including distant relatives of arthropods such as crabs and lobsters and a wide variety of worms.

The research team was led by professor Xianguang Hou from the Yunnan Key Laboratory for Palaeobiology at Yunnan University in China with collaboration from the Universities of Leicester and Oxford.