Pompeii trilobite fossils dating back 508 million years show features never seen before

A 508-million-year-old trilobite has been found preserved in volcanic material, revealing unprecedented detail in 3D. Its 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 pyroclastic flow, the hot, dense material that erupts from volcanoes and sometimes reaches speeds of up to 200 m (656 ft) per second. Normally, it incinerates any life in its path, but this can change in the marine environment.

“The sea surface onto which the ash flowed would have been deadly hot, and yes, it would have burned animals at its deepest depths,” one of the study’s authors said. Dr. Greg Edgecombe From the Natural History Museum, London, to IFLScience. “The ash likely mixed with seawater during its capture and trapping of trilobites that lived on the sea floor. This mixing in a column of seawater must have cooled the ash sufficiently.”

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.

It is about 508 million years old, younger than the oldest known trilobite, which dates back about 521 million years. There are also older burrow-shaped trace fossils, called Rusophycus, which are thought to be the work of trilobites and are over 528 million years old.

However, the grouper fish is still remarkable in the degree of preservation it shows.

“What makes our specimens unique, especially pristine, is the preservation of their three-dimensional appendages,” Edgecombe continued. “The appendages are not flattened, reoriented or broken. They are preserved in their proximal life orientations. Because they are preserved as empty space in the stony matrix, we can image them cross-sectionally to see them in 3D.”

“Appendages preserved in shale can preserve their bristles beautifully, but the fossils are so compressed that they are almost two-dimensional, and we have to use destructive sampling to mechanically drill out the upper parts of the appendages in order to see the lower ones. Our specimens are as perfect after study as they were.” before.”

These never-before-seen details mean we now see the 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 was published in the journal Sciences.