Western Europe’s oldest face adds new wrinkles to human evolution

A Spanish cave has divulged the oldest known fossil remains of human ancestors in Western Europe.

Excavations at a site known as Sima del Elefante produced several fossil fragments that, when pieced together, form a partial left upper jaw and cheek bone dated to between 1.4 million and 1.1 million years old, say zooarchaeologist Rosa Huguet of the Catalan Institute of Human Paleoecology and Social Evolution in Tarragona, Spain, and colleagues.

That ancient midface comes from a previously unknown European Homo population, the researchers report March 12 in Nature.

“This discovery introduces a new actor in the story of human evolution in Europe,” Huguet said at a March 11 press briefing.

Some features of the jaw and cheek resemble those of Homo erectus individuals who reached a site called Dmanisi, in what’s now the Southwest Asian nation of Georgia, around 1.8 million years ago. But not enough evidence exists to determine whether the new find qualifies as H. erectus or as a separate species, the investigators say.

Huguet’s team digitally scanned each fossil fragment to create a virtual, 3-D version of the entire ancient midface. A mirror image of the reassembled left-side fossils was used to portray the right side of the virtual midface.

A lower jaw fossil previously unearthed at Sima del Elefante dates to between roughly 1.2 million to 1.1 million years ago and may have belonged to the same unnamed Homo species as the facial fossil, they suggest.

Hominid fossils excavated over the past 30 years at Gran Dolina, a cave located near Sima del Elefante, come from a species Huguet’s group calls Homo antecessor, which lived between roughly 900,000 and 800,000 years ago. Vertically oriented, flat cheek bones of H. antecessor resemble those of people today, unlike the older Sima del Elefante face fossils.

Evolutionary ties between those two ancient European Homo species remain unclear. Members of the Sima del Elefante species — who also left behind a small collection of simple stone cutting or chopping tools — might have survived until shortly after the arrival of H. antecessor, the researchers say. In support of that scenario, animal bones and plant remains excavated in the same sediment as the ancient midface fossils reflect mild temperatures and a setting dotted with meadows, woods, shrubs and streams.

If recent evidence holds up of extreme cold temporarily driving hominid populations out of Europe shortly before 1.1 million years ago, then the Sima del Elefante Homo species may have died out before H. antecessor arrived, the scientists say.

Huguet’s group presents a carefully reconstructed midface for one of the oldest known European hominids, says Harvard University biological anthropologist G. Philip Rightmire, who did not participate in the new study. He suspects, though, that the ancient Sima del Elefante crowd belonged to H. erectus.

Fossil remains of four H. erectus faces at Dmanisi display considerable variation in nasal structure and other midface traits, Rightmire says. One of those faces aligns closely with the Spanish midface discovery, he contends. After H. erectus left Africa, “I would put my money on a long-lasting regional [H. erectus] population occupying Dmanisi around 1.8 million years ago, with later populations moving into Europe,” Rightmire says.