New analysis of a jawbone found in what is now modern Spain suggests it may be the earliest known example of a human fossil found in Europe

For over a century, one of the earliest human fossils ever discovered in Spain has been long considered a Neanderthal. However, new analysis from an international research team, including scientists at Binghamton University, State University of New York, dismantles this century-long interpretation, demonstrating that this fossil is not a Neanderthal; rather, it may actually represent the earliest presence of Homo sapiens ever documented in Europe.

In 1887, a fossil mandible was discovered during quarrying activities in the town of Banyoles, Spain, and has been studied by different researchers over the past century. The Banyoles fossil likely dates to between approximately 45,000-65,000 years ago, at a time when Europe was occupied by Neanderthals, and most researchers have generally linked it to this species.

Brian Keeling, a Binghamton University graduate student, said: “The mandible has been studied throughout the past century and was long considered to be a Neanderthal based on its age and location, and the fact that it lacks one of the diagnostic features of Homo sapiens; a chin.”

The new study relied on virtual techniques, including CT scanning of the original fossil. This was used to virtually reconstruct missing parts of the fossil, and then to generate a 3D model to be analysed on the computer.

The authors studied the expressions of distinct features on the mandible from Banyoles that are different between our own species, Homo sapiens, and the Neanderthals, our closest evolutionary cousins.

The authors applied a methodology known as ‘three-dimensional geometric morphometrics’ that analyses the geometric properties of the bone’s shape. This makes it possible to directly compare the overall shape of Banyoles to Neanderthals and H. sapiens.

Keeling said: “Our results found something quite surprising – Banyoles shared no distinct Neanderthal traits and did not overlap with Neanderthals in its overall shape.”

See also: First Neanderthal family unearthed by DNA

earlier human species

While Banyoles seemed to fit better with Homo sapiens in both the expression of its individual features and its overall shape, many of these features are also shared with earlier human species, complicating an immediate assignment to Homo sapiens. In addition, Banyoles lacks a chin, one of the most characteristic features of Homo sapiens mandibles.

Rolf Quam, professor of anthropology at Binghamton University, added: “We were confronted with results that were telling us Banyoles is not a Neanderthal, but the fact that it does not have a chin made us think twice about assigning it to Homo sapiens.

The presence of a chin has long been considered a hallmark of our own species.”

Given this, reaching a scientific consensus on what species Banyoles represents is a challenge. The authors also compared Banyoles with an early Homo sapiens mandible from a site called Peştera cu Oase in Romania. Unlike Banyoles, this mandible shows a full chin along with some Neanderthal features, and an ancient DNA analysis has revealed this individual had a Neanderthal ancestor four to six generations before.

Since the Banyoles mandible shared no distinct features with Neanderthals, the researchers ruled out the possibility of mixture between Neanderthals and H. sapiens to explain its anatomy.

prime candidate

The authors point out that some of the earliest Homo sapiens fossils from Africa, predating Banyoles by more than 100,000 years, do show less pronounced chins than in living populations.

Thus, the scientists developed two possibilities for what the Banyoles mandible may represent: a member of a previously unknown population of Homo sapiens that coexisted with the Neanderthals; or a hybrid between a member of this Homo sapiens group and a non-Neanderthal unidentified human species.

However, at the time of Banyoles, the only fossils recovered from Europe are Neanderthals, making this latter hypothesis less likely.

Keeling stated: “If Banyoles is really a member of our species, this prehistoric human would represent the earliest H. sapiens ever documented in Europe.”

Whichever species this mandible belongs to, Banyoles is clearly not a Neanderthal at a time when Neanderthals were believed to be the sole occupants of Europe.

The authors conclude that: “The present situation makes Banyoles a prime candidate for ancient DNA or proteomic analyses, which may shed additional light on its taxonomic affinities.”

The authors plan to make the CT scan and the 3D model of Banyoles available for other researchers to freely access and include in future comparative studies, promoting open access to fossil specimens and reproducibility of scientific studies.

Image: Comparison of the Banyoles mandible (centre), with H. sapiens (left), and a Neanderthal (right). © Brian Keeling.