3D reconstruction of one of the trilobite fossils
Arnaud Mazurié/University of Poitiers
A fossil site in Morocco has been dubbed the “Pompeii of trilobites” because it contains exquisitely detailed fossils of creatures preserved after an ash flow from a volcanic eruption some 509 million years ago.
“My jaw fell on the desk,” he said. John Patterson From the University of New England in Armidale, Australia. “I have never seen the level of detail preserved in these fossil trilobites. They are without a doubt the best preserved trilobites ever discovered.”
Trilobites are marine arthropods that existed from about 520 million years ago to about 252 million years ago. We know of more than 22,000 species and countless fossils have been discovered, but these are usually just hard exoskeletons. The soft parts of these creatures are only rarely found, and are always flattened and damaged.
But the moment Patterson saw scans and images of a trilobite fossil collected southwest of Marrakech, Morocco in 2022, he knew it was something special.
“In one of the most complete specimens, every appendage, down to the hairs on the walking leg, is preserved in 3D,” he says.
This fossil shows the digestive tract (blue), hypostome (green), labrum (red), and selected appendages.
Arnaud Mazurier/University of Poitiers
So far, Paterson and his colleagues have collected four specimens, each just over a centimeter long, representing two species from the Tatelt Formation in Morocco. Two of the four trilobite specimens belong to the genus. ProtolenusHowever, researchers are not sure whether it belongs to a new species. Other specimens Gigotella Mauretanica.
Pompeii is prized by archaeologists because the ash from Mount Vesuvius quickly descended on the Roman city, preserving its structures and inhabitants. As the ash cooled and formed into rock, each body disintegrated, leaving behind a hole that represents a perfect mold. The same thing happened to trilobites, Patterson says.
The team was able to scan the mold with a micro-CT scanner to create a complete 3D image of the creature. “With this specimen, you can look at it from any angle you want,” Paterson says.
The scans allowed the team to resolve important details that had long been debated, such as the trilobite’s anatomy. One individual had a digestive tract that was clearly preserved, filled with volcanic material, suggesting it had ingested ash when it died.
Another insight was how the creatures used their legs. “There are very nasty-looking spines on the inside of the leg,” says Patterson. “These would have acted like crushing tools for whatever their prey was. This means that they chewed their food with their legs and pushed the food up from their legs to their mouths.”
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