Ancient balloon-shaped animal fossil unveils new information on Earth’s ancient seas

‘Nidelric pugio’ named in honour of University of Leicester scientist who passed away earlier this year.

Nidelric pugio fossil dates back half a billion years and teaches us about the diversity of life in Earth’s ancient seas. In life the animal was a ‘balloon’ shape, covered in spines but the squashed fossil resembles a bird’s nest. The fossil has been named in honour of Professor Richard Aldridge from the University of Leicester.

This rare 520 million year old fossil has been discovered in China by an international research team.

The research team behind the discovery 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.

The fossil, from Chengjiang in southern China, is of a probably ‘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.


Funded by the National Science Foundation in China and the Royal Society in the UK, the research team named the species Nidelric pugio as a way to honour the late Professor Richard Aldridge, and internationally renowned palaeontologist and keen ornithologist formerly from the University of Leicester’s Department of Geology and a scientist who was a world leader in Chengjiang fossil research.

The name of the fossil has derived from the Latin Nidus, meaning ‘bird’s nest’ or ‘fancied resemblance to’ and alderic, derived from the Old English personal name ‘Aedelic’ – ‘adel’ meaning ‘nobel’ and ‘ric’ meaning ‘a ruler’ – which is a source for the name Aldridge.

Dr. Tom Harvey from the University of Leicester, a co-author of the paper, said: “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.

“We are glad the fossil can honour the name of Professor Richard Aldridge, who was a leader in this field and whose research was vital in better understanding the rich tapestry of fossils found at Chengjiang.”

In southern China, rocks 520 million years old in Chengjiang County, Yunna Province generate a diverse array of fossils preserved with traces of their soft anatomy, including their legs, eyes, guts and even brains.

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

There are also several enigmatic fossils that don’t appear to fit with anything living today, and amongst these are the chancelloriids.

The fossils enable an unprecedented view of life in Earth’s ancient seas.

Tom Hearing, a PhD student from the Department of Geology who is working on the skeletons of Cambrian fossils, added: “We usually only get the broken-up remains of ancient animal skeletons. With this specimen we can see how all the different parts of the skeleton stuck together. It tells us much about how early animals functioned, how they might have interacted with other animals, and how they might have protected themselves from predators.”

Contributing Source: University of Leicester

Header Image Source: Prof Derek J Siveter of Oxford University


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