Paleontologists are marveling over the unique fossil of a marine species that predated the dinosaurs.
The fossil, dated to about 444 million years ago, contained a new species of arthropod that fossilized inside-out, according to a paper published in the journal Palaeontology.
The discovery was described by researchers as a “legless, headless wonder,” according to a statement from the University of Leicester.
The “exceptionally preserved” euarthropod was found with its muscles, sinews, tendons and guts all preserved in “unimaginable detail,” said Sarah Gabbott, a professor at the University of Leicester’s school of geology and lead author of the paper.
“Remarkably her insides are a mineralised time-capsule,” Gabbott said, adding that the specimen’s head and legs were lost to decay over hundreds of millions of years.
The new species was dubbed “Keurbos susanae” or “Sue” — after the mother of the woman who discovered it. Researchers are certain it is a primitive marine arthropod, but the precise evolutionary relationships remain “frustratingly elusive,” Gabbott said.
The fossil was located on Soom Shale, a band of silts and clays about 250 miles north of Cape Town, South Africa. At the time the strata was laid down, a “devastating” glaciation had wiped out about 85% of Earth’s species — one of the “big five” mass extinctions in Earth’s history, the researchers said.
But the marine basin where Sue was found was somehow protected from the worst of the freezing conditions and provided shelter for a community of “fascinating” species, according to the paper.
The downside to Sue’s unique fossilization is it makes it hard to compare the specimen with other fossils of similar species of the time.
“So it remains a mystery how she fits into the evolutionary tree of life,” according to the researchers.