444-Million-Year-Old Exceptionally Rare Fossil Find Stuns Professor: 'Inside-Out, Legless, Headless Wonder'

Fossil discoveries have long provided crucial details regarding Earth’s prehistoric past, facilitating glimpses into species that loitered the planet millions of years ago. Most fossils capture the solid remains of external features—shells, bones, and exoskeletons—providing paleontologists a chance to revamp ancient life forms. However, now and then, a fossil emerges that defies all the rules and understandings of experts, challenging the way scientists understand preservation and evolution, stated BBC.

In a stunning revelation, Professor Sarah Gabbott from the University of Leicester has spilled the details of an exceptionally rare fossil she has been studying for 25 years. Dating back 444 million years to the Late Ordovician period, this fossil is not just any common fossil seen before—it is an "inside-out, legless, headless wonder." Gabbott noted, "Sue is an inside-out, legless, headless wonder…Remarkably her insides are a mineralised time-capsule: muscles, sinews, tendons and even guts all preserved in unimaginable detail…And yet her durable carapace, legs and head are missing – lost to decay over 440 million years ago…We are now sure she was a primitive marine arthropod but her precise evolutionary relationships remain frustratingly elusive," stated BBC.

Intriguingly, the fossil has been rebranded as a new species of marine arthropod named Keurbos susanae. This has left experts too stunned to speak. Gabbott noted, "This has been an ultramarathon of a research effort. In a large part because this fossil is just so beautifully preserved, there's so much anatomy there that needs interpreting. Layer upon layer of exquisite detail and complexity. I'd always hoped to find new specimens, but it seems after 25 years of searching, this fossil is vanishingly rare – so I can hang on no longer…Recently, my mum said to me, 'Sarah if you are going to name this fossil after me, you'd better get on and do it before I am in the ground and fossilized myself.'" As time passed, a search for additional specimens was next to impossible, making this a true gem of a find. The fossil’s internal anatomy—muscles, tendons, sinews, and even gut structures—has been mineralized in an awestruck manner, according to Live Science.

The fossil’s stunning preservation is attributed to the highly unusual conditions in which it was buried. Sue was found in all its glory in fine-grained silt and clay on an ancient seafloor in an oxygen-poor environment saturated with hydrogen sulfide. In a statement, Gabboott noted, "We are now sure she was a primitive marine arthropod, but her precise evolutionary relationships remain frustratingly elusive," stated Live Science

The discovery holds prominence beyond its bizarre preservation. Sue’s time overlaps with the Late Ordovician mass extinction, a deadly event that wiped out approximately 85% of marine species. Gabbott noted, "I tell my mum in jest that I named the fossil Sue after her because she is a well-preserved specimen. But, in truth, I named her Sue because my mum always said I should follow a career that makes me happy – whatever that may be. For me, that is digging rocks, finding fossils and then trying to figure out how they lived and what they tell us about ancient life and evolution on Earth," stated BBC.