New fossils of trilobites — arthropods that lived in the sea around 500 million years ago — discovered by researchers in Morocco are the best preserved fossils of the class ever recorded.
The fossils were found in the High Atlas, in the Moroccan mountain ranges, and the discovery is being called by scientists “Pompeii of the trilobites“. The animals were fossilized under the ash of a prehistoric volcano in the region, remaining extraordinarily well preserved, in a similar way to the victims of Mount Vesuvius, which hit the Italian city of Pompeii in the 1st century.
Trilobites lived during the Cambrian period, between 500 and 400 million years ago, in shallow seas that covered much of the megacontinent Pangea. They resembled cockroaches, covered with a chitin exoskeleton, and the largest could reach 70 or 80 centimeters in length.
A research was published in the journal Science on Thursday (27). The team was led by Abderrazak El Albani, a geologist at the University of Poitiers and originally from Morocco.
“As a scientist who has worked with fossils of different ages and locations, discovering fossils in such a remarkable state of preservation in a volcanic environment was a deeply stimulating experience for me,” said Abderrazak. “I believe that pyroclastic deposits [locais devastados por erupções vulcânicas] should become new targets of study, given their exceptional potential to capture and preserve biological remains, including delicate soft tissues.”
“These findings are expected to lead to significant discoveries about the evolution of life on our planet Earth,” added the geologist.
Amazingly well-preserved fossils
As they have a hard, calcified exoskeleton, trilobite fossils are often found in good condition, making this one of the extinct marine animals best studied by scientists — more than 20,000 species of trilobites have already been recorded by paleontologists.
However, understanding of the animals has been limited by the paucity of preservation of their soft tissues in fossils.
“I’ve been studying trilobites for almost 40 years, but I’ve never felt like I was looking at live animals as much as I do with these [fósseis]. I had already seen the anatomy of trilobite soft tissues, but the 3D preservation of these is truly astonishing,” said Greg Edgecombe, a paleontologist at the Natural History Museum who was also part of the study.
“An unexpected result of our work is discovering that volcanic ash in shallow marine environments can be a goldmine for exceptional fossil preservation,” Edgecombe added.
Because the trilobites found in Morocco were encased in hot ash from the volcano in seawater, their bodies fossilized very quickly as the ash turned to rock, preserving details that are often lost in fossils (as with the inhabitants of Morocco). Pompeii after the eruption of Vesuvius).
New discoveries
Using CT scans and virtual X-ray modeling, researchers have already made some new discoveries about trilobites from these fossils.
They found appendages at the edge of the trilobites’ mouths with curved, spoon-shaped bases that were so small they were not detected in less perfectly preserved fossils.
Scientists previously thought trilobites had three pairs of head appendages behind their long antennae, but both Moroccan species in this study showed there were four pairs.
Additionally, a fleshy lobe covering the mouth, like a lip, was first documented in trilobites.
“The results revealed in exquisite detail a cluster of pairs of specialized legs around the mouth, giving us a clearer picture of how trilobites fed. The head and body appendages were found to have a battery of dense inward-facing spines, like those of today’s horseshoe crabs,” explained co-author Harry Berks from the University of Bristol.
565-million-year-old fossils reveal secrets of evolution on Earth
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