Trilobites dating back 508 million years have been found preserved in volcanic material, revealing never-before-seen detail in 3D. Their fossilization was so rapid that tiny shells were preserved in place, and soft tissue including mouthparts and internal organs can still be seen.
The trilobites were buried in volcanic flow, the hot, dense material that erupts from volcanoes and sometimes reaches speeds of up to 200 meters (656 feet) per second. Normally, it incinerates any life in its path, but this can change in a marine environment.
“The sea surface onto which the ash flowed would have been deadly hot, and would have burned animals at shallow depths,” says the study co-author. Dr. Greg Edgecombe “The ash must have mixed with seawater as it picked up and carried the trilobites that lived on the sea floor. This mixing through the seawater column must have cooled the ash sufficiently,” the archaeologist at London’s Natural History Museum told IFLScience.
The ancient wonders, collected in the High Atlas of Morocco, were given the name “Pompeii” trilobites due to their remarkable preservation in ash. They’re incredibly old, but they’re not the oldest trilobites ever found.
At about 508 million years old, they are younger than the oldest trilobites, which date back to about 521 million years ago. There are also older burrow-shaped trace fossils, called Rusophycus, which are believed to be the work of trilobites and are over 528 million years old.
However, whip snappers are still remarkable for the degree of preservation they exhibit.
“What makes our specimens unique, especially pristine ones, is the preservation of their appendages in 3D,” Edgecombe continued. “The appendages are not flattened, reoriented or broken. They are preserved in the orientations of near-life. And because they are preserved as empty space in the rock matrix, we can image them in tomography to see them in 3D.”
Microscopic reconstruction of the trilobite Gigoutella mauretanica in ventral view.
Image credit: © Arnaud MAZURIER, IC2MP, University. Poitiers
“Appendages preserved in shale can preserve their shape beautifully but the fossils are so compressed that they are almost two-dimensional and we have to use destructive samples to mechanically coring the upper parts of the appendage in order to see the lower parts. Our specimens are as perfect after study as they were before.”
These never-before-seen details mean we now see trilobites closer to real life than we’ve ever seen them before, complete with a slit-like mouth and unique vertical feeding appendages. Is not she beautiful?
The study is published in the journal Sciences.