Researchers are studying one of the best-preserved trilobite fossils ever discovered, which are about 500 million years old.
The well-preserved and three-dimensional fossils recovered from the High Atlas of Morocco are being referred to as ‘Pompeii’ trilobites by researchers due to their exceptional quality.
The fossilization process involving volcanic ash in shallow marine settings has led to 3D preservation, according to the researchers.
The fossilization process
According to researchers, trilobites are some of the best-studied fossil marine animals due to their hard, calcified exoskeleton often being well-preserved.
To date, paleontologists have described over 20,000 species in the past two centuries.
However, a comprehensive scientific understanding of the diverse trilobite group has been hindered by the relative rarity of soft tissue preservation. But the most recent discovery has put an end to this long-standing search.
According to the research paper, the Moroccan trilobites were encased in hot ash within seawater, leading to rapid fossilization of their bodies as the ash transformed into rock.
“The ash molds preserved each segment of their bodies, their legs and even the hair-like structures that ran along the appendages. The trilobites’ digestive tract was also preserved after it filled with ash. Even small ‘lamp shells’ attached to the trilobites’ exoskeleton remained attached by fleshy stalks as they were in life,” the paper says.
This fate, similar to that of the inhabitants of Pompeii following the eruption of Mount Vesuvius, led to the name ‘Pompeii’ trilobites.
Dr Greg Edgecombe, a paleontologist at the Natural History Museum, said, “I’ve been studying trilobites for nearly 40 years, but I never felt like I was looking at live animals as much as I have with these ones.”
“I’ve seen a lot of soft anatomy of trilobites, but it’s the 3D preservation here that is truly astounding.”
Findings from the ‘Pompeii’ trilobite fossils
Using CT scanning and computer modeling of virtual X-ray slices, the researchers discovered that appendages found at the edge of the mouth had curved spoon-like bases but were so small that they had gone undetected in less perfectly preserved fossils.
In fact, it had previously been thought that trilobites had three pairs of head appendages behind their long antennae, but both Moroccan species in this study showed that there were four pairs.
A fleshy lobe covering the mouth, called a labrum, was documented for the first time in trilobite, all thanks to the Moroccan samples.
Lead author, Professor Abderrazak El Albani, said, “I think pyroclastic deposits should become new targets for study, given their exceptional potential for trapping and preserving biological remains, including delicate soft tissues.”
“These findings are anticipated to lead to significant discoveries about the evolution of life on our planet Earth.”
Co-author Harry Berks, from the University of Bristol, said that the results revealed a clustering of specialized leg pairs around the mouth, “giving us a clearer picture of how trilobites fed.”
“The head and body appendages were found to have an inward-facing battery of dense spines, like those of today’s horseshoe crabs,” Berks added.
The paper was originally published in the journal Science.
