At a Glance
- Scientists discovered a 444-million-year-old fossil named Keurbos susanae in South Africa, uniquely preserved with internal anatomy like muscles and gut, offering rare insights beyond typical fossilized exteriors.
- Professor Sarah Gabbott led the study, describing the fossil as an “inside-out, legless, headless wonder” due to its remarkable preservation of soft tissues while outer features like head and limbs decayed.
- The fossil dates to a period just after a major mass extinction and was preserved in a toxic, oxygen-deprived marine environment that helped maintain delicate internal structures over millions of years.
- Keurbos susanae is hard to classify within known evolutionary lineages due to its unusual fossilization, which complicates comparisons with other ancient arthropods from the same time.
- Researchers believe this fossil could provide key insights into early arthropod evolution, and ongoing studies may reveal more about ancient life and survival after Earth’s mass extinction events.
A new fossil discovery has offered scientists a remarkable look into ancient life from 444 million years ago. Named Keurbos susanae, this species of ancient arthropod was found preserved in the Soom Shale in South Africa, a site known for its excellent preservation of ancient creatures. This fossil is unique because it shows the internal anatomy of the creature, such as muscles, tendons, and even its gut, in extraordinary detail, unlike most fossils that only preserve the external features of organisms.
The fossil was uncovered by Professor Sarah Gabbott from the University of Leicester after 25 years of research. Gabbott, who led the study published in Palaeontology, described the fossil as “an inside-out, legless, headless wonder.” This is because, unlike typical fossils, which often preserve only hard outer shells, K. susanae’s internal features were mineralized and preserved in the sediment over millions of years. However, the creature’s head and legs have decayed, leaving only the body’s internal structures intact.
The fossil comes from just after one of Earth’s major mass extinctions when much of the planet’s life was wiped out. The marine environment where the fossilized creature lived was toxic, with no oxygen and harmful hydrogen sulfide in the water. This unusual combination of conditions may have helped preserve the creature’s soft tissues, providing a rare snapshot of life during a challenging time in Earth’s history.
Despite the fossil’s incredible preservation, fitting K. susanae into the evolutionary tree is difficult. The unusual preservation of its internal features makes it challenging to compare with other fossils from the same era. Still, scientists are hopeful that further studies of the fossil, along with similar future discoveries, will shed more light on the evolution of early arthropods and other ancient creatures.
References
- University of Leicester. (2025, March 27). ‘Inside out’ fossil reveals a new species with a perfectly preserved interior. Phys.Org; University of Leicester. https://phys.org/news/2025-03-fossil-reveals-species-interior.html
- Gabbott, S. E., Edgecombe, G. D., Theron, J. N., & Aldridge, R. J. (2025). A new euarthropod from the Soom Shale (Ordovician) Konservat‐Lagerstätte, South Africa, with exceptional preservation of the connective endoskeleton and myoanatomy. Papers in Palaeontology, 11(2), e70004. https://doi.org/10.1002/spp2.70004
