Skull shape analysis highlights migratory movements in Ancient Rome

June 20 (UPI) -- New analysis of ancient skulls suggest communities along the coast of Italy remained stable and relatively isolated during the first through third centuries, while the Roman capital enjoyed an influx of immigrants.

Scientists at North Carolina State University and California State University, Sacramento digitized and analyzed the shapes of dozens of human skulls collected from three imperial Roman cemeteries.

The two coastal cemeteries, Isola Sacra and Velia, housed the remains of middle-class merchants and tradesmen, while the inland cemetery, Castel Malnome, located on the outskirts of the city of Rome, served as a final resting place for manual laborers.

Analysis of the skulls' shapes -- a field of study known as "geometric morphometrics" -- revealed similarities and differences between the three populations.

"We found that there were significant cranial differences between the coastal communities, even though they had comparable populations in terms of class and employment," Ann Ross, a professor of anthropology at NC State, said in a news release.

"We think this is likely due to the fact that the area around Velia had a large Greek population, rather than an indigenous one," said Samantha Hens, a professor of biological anthropology at Sacramento State.

The skulls from the outskirts of Rome revealed a greater degree of similarity to the two coastal communities than the coastal populations shared with each other.

"This likely highlights the heterogeneity of the population near Rome, and the influx of freed slaves and low-paid workers needed for manual labor in that area," Hens said.

Scientists have previously used linguistics, genetics and teeth fossils to trace the migration patterns of Roman populations.

Researchers believe their study -- published in the International Journal of Osteoarchaeology -- is the first to apply geometric morphometrics to skulls excavated from imperial Roman burial sites.

"That's important because geometric morphometrics offers several advantages," Ross said. "It includes all geometric information in three-dimensional space rather than statistical space, it provides more biological information, and it allows for pictorial visualization rather than just lists of measurements."

Cranial analysis can not only help scientists track the makeup and movements of ancient communities, the technique can also reveal what people from the past actually looked like.