Clinically called Keurbos susanae and nicknamed ‘Sue’after its innovator’s mum, the ancient arthropod lived throughout the Ordovician duration, around 444 million years back.

“Sue is an inside-out, legless, headless marvel,”stated University of Leicester’s Professor Sarah Gabbott, author of the research study.

“Remarkably her withins are a mineralized time-capsule: muscles, sinews, tendons and even guts all protected in inconceivable information.”

“And yet her resilient carapace, legs and head are missing out on– lost to decay over 440 million years earlier.”

“We are now sure she was a primitive marine arthropod however her accurate evolutionary relationships stay frustratingly evasive.”

“Today about 85% of animals in the world are arthropods, and they consist of shrimps, lobsters, spiders, termites, millipedes and centipedes.”

“They have an outstanding fossil record extending back over 500 million years however normally their fossil remains are of their external functions, whereas ‘Sue’ is the total reverse since it is her withins that are fossilized.”

The fossilized specimen of Keurbos susanae was discovered in the Soom Shale in South Africa.

“These strata were put down on the seafloor over 440 million years earlier at a time when a destructive glaciation had actually erased about 85% of Earth’s types– among the huge 5 mass terminations,” Professor Gabbott stated.

“It appears that the marine basin in which ‘Sue’ swam was in some way secured from the worst of the freezing conditions and an interesting neighborhood of animals, consisting of ‘Sue,’ took haven there.”

“The conditions in the sediments where ‘Sue’ came to rest were hazardous in the extreme.”

“There was no oxygen however even worse than that there was fatal– and stinking– hydrogen sulfide liquified in the water.”

The scientists believe that an unusual chemical alchemy was at operate in producing the fossil and its uncommon inside-out conservation.

“But there is a disadvantage, due to the fact that the special conservation of ‘Sue’ makes it hard to compare her to other fossils of the period therefore it stays a secret how she suits the evolutionary tree of life,” Professor Gabbott kept in mind.

“The little roadside quarry, where I discovered the fossils 25 years earlier at the start of my scholastic profession, has all however vanished therefore other specimens are not likely to be discovered.”

“The fossil was exceptionally hard to analyze and I held out hope of discovering another specimen with its head or legs undamaged.”

The research study will be released in the journal Palaeontology

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Sarah Gabbott. 2025. A brand-new euarthropod from the Soom Shale (Ordovician) Konservat-Lagerstätte, South Africa, with extraordinary conservation of the connective endoskeleton and myoanatomy. Palaeontologyin press; doi: 10.1002/ spp2.70004