The mystery of an extinct animal fossil used as an amulet by the Romans has been unraveled.

The mystery of the trilobite fossil found in 2021 in the Roman city of Armea , located in the municipality of Allariz (Orense), has finally been unraveled thanks to the joint work of archaeologists and paleontologists from the University of Vigo and the Complutense University of Madrid, published in the journal 'Archaeological and Anthropological Sciences '. It is the first known specimen from Roman times of this class of arthropods extinct for about 250 million years.

The small fossil was found in the dumping grounds of a manor house dating from the 1st to 3rd centuries, along with fragments of pottery, bone, and metal. The archaeologist in charge of the excavation, Adolfo Fernández-Fernández, from the Orense campus of the University of Vigo, and the paleontologist from the same university, Manuel García-Ávila, sent it to specialists at the Complutense University for further study.

Complutense paleontologists Juan Carlos Gutiérrez-Marco and Sara Romero concluded that it was a molted remains of a species about 453-460 million years old that had been intentionally manipulated into a hemispherical object. The experts observed seven wear facets that flattened and shaped the fossil, probably for use mounted on a leather bracelet or as a pendant , a family talisman or personal amulet with magical or protective properties.

It did not come from any Galician site or any other location in the northwest of the Iberian Peninsula. Due to its taphonomic characteristics (fossilized material, rock alteration, lack of deformation), it could only come from "a few locations in Spain, more than 400 linear kilometers away from where it was found," the UCM notes in a statement.

Finally, the most likely source was a region in the province of Ciudad Real, bordering Badajoz . There, according to the statement, "tiles formed by the intensive paleoalteration of fossil-bearing marine rocks" containing trilobites were mined in ancient times.

Armea was linked to the mining trade through the silver route , which is why archaeologists deduce that this was the route the fossil followed to the Roman city.

In addition to representing the first known trilobite from Roman times, paleontologists conclude that this specimen represents the eleventh known element worldwide and the sixth trilobite incorporated into human cultures more than a thousand years ago.