Moroccan researcher Abderrazak El Albani led a group of researchers in discovering a prehistoric “Pompeii,” with examples of the most pristine trilobite fossils ever found, shaking up previous scientific understanding, Science Daily reported on Thursday.
The 515-million-year-old fossils were discovered in Morocco’s High Atlas mountains and are known as “Pompeii” trilobites due to their extraordinary preservation in volcanic ash.
The Moroccan geologist based at the University of Poitiers, France, conducted the study on the Cambrian trilobites with a team that included Dr. Greg Edgecombe, a paleontologist at the American Natural History Museum.
Prof. El Albani, the lead author, said, “As a scientist who has worked on fossils of all ages and places, discovering fossils in such a fantastic level of preservation inside a volcanic context was a truly gratifying experience for me.”
He added, “I think pyroclastic deposits should become new targets for study, given their exceptional potential for trapping and preserving biological remains, including delicate soft tissues.”
Dr. Edgecombe likewise remarked, “I’ve been researching trilobites for about 40 years, and I’ve never felt like I was looking at live animals as much as I did with these. I’ve seen a lot of soft anatomy in trilobites, but the 3D preservation here is simply remarkable.”
Trilobites are among the most well-studied fossil marine organisms because of their strong, calcified exoskeleton, which is frequently well-preserved. Paleontologists have described more than 20,000 species during the last two centuries.
However, the lack of soft tissue preservation has hampered the complete scientific study of this incredibly varied group up until now. Because the Moroccan trilobites were imprisoned in hot ash in seawater, their corpses fossilized swiftly as the ash converted into rock, suffering a fate comparable to the residents of Pompeii following the eruption of Mount Vesuvius.
The ash molds maintained every part of their bodies, including their legs and the hair-like coverings that ran along their appendages. The trilobites’ digestive tract was also preserved after being filled with ash. Even little “lamp shells” connected to the trilobites’ exoskeleton retained the same fleshy stalks as they did in life.
Using CT scanning and computer modeling of virtual X-ray slices, the researchers determined that appendages located near their mouth opening had bent spoon-like bottoms, but they were so minuscule that they had previously gone unnoticed in less thoroughly preserved fossils.
Previously, scientists thought that trilobites had three pairs of head appendages behind their long antennae, but this study found that both Moroccan species had four pairs.
A fleshy lobe surrounding the mouth, known as a labrum, was discovered for the first time in trilobites.
Co-author Harry Berks of the University of Bristol commented, “The results revealed in exquisite detail a clustering of specialized leg pairs around the mouth, giving us a clearer picture of how trilobites fed.”
The head and body appendages were also discovered to feature an inward-facing battery of thick spines, similar to those observed in modern horseshoe crabs.