The oldest known fossil of a human cranium has been uncovered in Portugal.

An international research team, directed by Portuguese archaeologist João Zilhão and including Binghamton University anthropologist Rolf Quam, found the cranium in a cave in Portugal, marking an important contribution to knowledge of human evolution during the middle Pleistocene in Europe and to the origin of the Neanderthals.

The cranium represents the westernmost human fossil ever found in Europe during the middle Pleistocene epoch and one of the earliest on the continent to be associated with the Acheulean stone tool industry.

Unlike other fossils found from the same time period—which are often poorly dated or lack a clear archaeological context—the cranium found in the cave of Aroeira is well-dated to 400,000 years ago, based on abundant faunal remains and stone tools, including numerous hand axes or bifaces.

“This is an interesting new fossil discovery from the Iberian Peninsula, a crucial region for understanding the origin and evolution of the Neanderthals,” Quam, an associate professor of anthropology at Binghamton University, State University of New York, said in a statement. “The Aroeira cranium is the oldest human fossil ever found in Portugal and shares some features with other fossils from this same time period in Spain, France and Italy.

“The Aroeria cranium increases the anatomical diversity in the human fossil record from this time period, suggesting different populations showed somewhat different combinations of features.”

Since the sediments containing the cranium—which was found in 2014—were firmly cemented, the cranium was removed from the site in a large, solid block.

The fossil was then transported to a paleoanthropology research center in Madrid for preparation and extraction, a process that took two years.

“The results of this study are only possible thanks to the arduous work of numerous individuals over the last several years,” Quam said. “This includes the archaeologists who have excavated at the site for many years, the preparator who removed the fossil from its surrounding breccia, researchers who CT scanned the specimen and made virtual reconstructions and the anthropologists who studied the fossil.

“This study truly represents an international scientific collaboration and I feel fortunate to be involved in this research.”

The new fossil represents the centerpiece of an exhibit on human evolution at the Museu Nacional de Arqueolgia in Lisbon.