Discovery of new fossil from half billion years ago sheds light on life on Earth

Scientists from the universities of Leicester and Cambridge have discovered a new species of fossil that will shed light on early animal ecosystems.

Dr Tom Harvey from our Department of Geology together with Professor Nicholas Butterfield, University of Cambridge, discovered the new species while conducting a survey of microfossils in mudstones from western Canada.

To their surprise, the samples yielded miniscule loriciferans: a type of animal so small it has been considered “unfossilizable”.

Fossil loriciferan

Moreover, the fossils date to the late Cambrian Period, meaning they lived around half a billion years ago. This suggests that soon after the origin of animals, some groups were adopting specialized “meiobenthic” lifestyles, living among grains of sediment on the seabed. 

Dr Harvey said: “I discovered the fossil loriciferans by accident while surveying other types of microfossil: this required many hours working at the microscope. I kept finding mysterious fragments which looked like the back ends of loriciferans, but I told myself it was impossible.

“Finally, however, I found an exceptionally well-preserved specimen with a fossilized head still in place, proving its identity as a loriciferan. Then began the delicate task of cleaning the fossil and securing it on a microscope slide.

“As well as being very small, loriciferans lack hard parts (they have no shell), so no-one expected them ever to be found as fossils – but here they are! The fossils represent a new genus and species, which we name Eolorica deadwoodensis, loosely meaning the “ancient corset-animal from rocks of the Deadwood Formation.”

“It’s remarkable that so early in their evolution, animals were already exploiting such specialized meiobenthic ecologies: shrinking their bodies down to the size of single-celled organisms, and living among grains of sediment on the seabed.”