Bizarre ‘nude’ creature fossil discovery poses so many questions

20 Jun 2018

An ammonite fossil unrelated to this recent find. Image: Jiri Vaclavek/Shutterstock

Palaeontologists have unearthed the fossilised remains of a truly bizarre creature from 500m years ago that doesn’t fit into our existing tree of life.

There have been some truly strange discoveries made about our ancient world that look as if they originated on an alien planet, but a new discovery of a bizarre fossil really has palaeontologists scratching their head as to what it is.

In a paper published to Proceedings of the Royal Society B, a team of researchers from the University of Leicester, the University of Oxford and Yunnan University in China revealed the fossilised remains of a large-bodied ‘nude’ sea creature that existed 500m years ago.

The species, dubbed Allonnia nuda, was discovered in the Yunnan province and belongs to a mysterious group of animals known as the chancelloriids, currently outside of the established tree of life drawn up by evolutionary biologists.

Its size, for one thing, has puzzled scientists. At up to 50cm or even more, its body only contained a few very tiny spines and represents a lineage of tube-shaped animals that arose during the Cambrian evolutionary explosion, but went extinct shortly afterwards.

Marine fossil sample

The new species of fossil chancelloriid, an enigmatic animal from the Cambrian Period with a tube-like body, ‘minotaur-horn’ spines and doughnut-shaped scars. Image: Derek Siveter/Tom Harvey/Peiyun Cong

Mystery not entirely solved

Additionally, its unusual ‘naked’ appearance suggests that further specimens may be ‘hiding in plain sight’ in fossil collections, and shows that this group was more diverse than previously thought.

The researchers now believe the discovery of this species could hold clues about the pattern of body growth in the creature, showing clear links between it and modern sponges. The comparison has drawn criticism in some scientific circles, though, with some describing the similarities as merely superficial.

While the creature’s mysteriousness remains, the discovery highlights the central role of sponge-like fossils in the debate over the earliest animal evolution.

“Fossil chancelloriids were first described around 100 years ago, but have resisted attempts to place them in the tree of life,” Dr Tom Harvey of the research team explained.

“We argue that their pattern of body growth supports a link to sponges, reinvigorating an old hypothesis. We’re not suggesting that it’s ‘case closed’ for chancelloriids, but we hope our results will inspire new research into the nature of the earliest animals.”

Colm Gorey was a senior journalist with Silicon Republic