Prehistoric rat-like mammal fossil is earliest showing fur, skin and organs
The 125m-year-old remains of Spinolestes xenarthrosus were so well preserved as to leave soft tissue parts intact Photograph: Georg Oleschinski A small rat-like mammal that lived and died in a swamp 125m years ago was so well preserved by the fossilisation process that its fur, skin and organs are still visible today. The remains, unearthed in a quarry near Cuenca in central Spain, are more than 60m years older than other fossils that record the soft tissues of prehistoric mammals. The animal’s ear lobe, lung and liver are all fossilised, along with its furry pelt and tiny hedgehog-like spines on its lower back that likely protected it from predators.
Researchers even found evidence of a fungal skin infection in the remains. Named Spinolestes xenarthrosus , the insect-eating furball was discovered in 2011 when fossil hunters at the Autonomous University of Madrid, were prising apart thin leaves of fine limestone sediment in the Las Hoyas Quarry. “The preservation of its soft parts is stunning,” Thomas Martin, a professor of paleontology at the University of Bonn who studied the fossil told the Guardian. “The hairs have the same structure and diversity as those seen on modern mammals.”
Small, stiff spines on the animal’s lower back are thought to have offered some protection from predators such as pelecanimimus , a many-toothed, metre-long ostrich-like creature that lived alongside Spinolestes . The back spines may have come off easily, filling predators’ mouths with hard, rigid spikes. These defences were bolstered by tiny scales on the animal’s lower back, much like primitive versions of armadillos’ plates. Artist’s impression of Spinolestes in the Cretaceous-period Las Hoyas wetland. Photograph: Oscar Sanisidro Martin believes the creature was so well preserved because bacterial films grew over the animal within hours of its death. These biofilms can form a protective […]