“Inside-Out” Fossil preserves internal organs for 440 million years

Sue is a wonder from inside out, without legs and without head.

Sorry for any people called Sue. The ‘Sue’ is the fossil of a creature that lived 440 million years ago.

Fossil’s discovery is announced in a new article published in the magazine Paleontology that identifies it as belonging to a new species, Keurbos Susanae. The organism is named after the mother of the discoverer, Sue.

It comes from the end of a period in the history of the Earth called Ordovician that lasted 485 to 444 million years (mya).

Ordovico is the second period of the Paleozoic era. The Paleozoic, which means “ancient life”, began with the appearance of various vegetables and animal life during the 541 mybric explosion.

At the end of the Ordovico, a devastating glaciation event had erased two thirds of a lifetime on earth. This was the first of the 5 mass extinctions of the 5 greats.

After the Ordovico arrived, the Silurian period (444–419 mya).

Silurian land was an oceanic world. The sea levels were much higher than today and the weather had stabilized their erratic past. Almost all his life on the planet was still under the surface in the old seas.

The corals were common and the fish were widespread. The greatest of these Silurian fish, Megamastax AmblyodusIt grew only 1m. The first vascular plants in Silurian were the first complex organisms to start making the transition to life on earth.

The arthropods were also common in the Ordovico and Siluriano. Arthropods have segmented bodies that are covered by a hard exoskeleton. About 85% of modern animal species are arthropods, including spiders, insects, crabs and millpiés.

A reason why paleontologists know so much about the ancient arthropods is because their exoskeleton or shell, fossilizes more easily than the soft body parts of other animals.

Sue broke the rules.

“Surprisingly, its interior is a mineralized time capsule: muscles, tendons, tendons and even guts preserved with unimaginable details,” says the main author Sarah Gabbott of the University of Leicester of the United Kingdom and daughter of Sue. “And yet, its shell, legs and coatsels are missing, losing the decomposition of more than 440 million years ago.”

The unique preservation of usually makes it difficult to compare K. Susanae To other examples of ancient arthropods, which makes the place of the creature in the tree of life a mystery.

“Now we are sure that she was a primitive marine arthropod, but her precise evolutionary relationships are still frustratingly elusive,” adds Gabbott.

The fossil was found in the shale of SOOM about 400 km north of Cape Town in South Africa. This late ordovic marine fund must have been protected from the worst freezing conditions that caused mass extinction.

K. Susanae It was among a community of strange animals that took refuge there. These included other arthropods such as maritime and trilobites scorpions, as well as cephalopods related to modern squid.

Gabbott found K. SusanaeS fossil along with other specimens about 25 years ago. The quarry on the road where they were unearthed has almost disappeared, which makes the future unlikely. Gabbott had hoped to find a specimen with legs to determine K. SusanaeThe evolutionary lineage.

“This has been an ultramarathon of a research effort,” says Gabbott. “In large part, because this fossil is so beautifully preserved, there is so much anatomy there that you need to interpret.

“Cap on a layer of exquisite details and complexity. I always expected to find new specimens, but it seems that after 25 years of search, this fossil is irritatingly rare, so I can no longer endure.

“I tell my mother jokingly that I called the Sue Fossil after her because she is a well preserved specimen,” says Gabbott. “But, really, I called her because my mother always said that I should follow a career that makes me happy, whatever it is. For me, that is to dig rocks, find fossils and then try to discover how they lived, what they tell us about ancient life and evolution on earth.”