Piecing together the story of Europe's earliest settlers is a challenge, largely because relevant human fossils are scarce. On March 12, researchers announced the discovery of a new fossil from the excavation site of Sime del Elefante, near Burgos in Spain.
Author
- Suzy White
Post-Doctoral Research Assistant, Ecology and Evolutionary Biology, University of Reading
Known as ATE7-1, the new fossil consists of a partial face belonging to an ancient hominin, a biological classification that includes living humans and our closest extinct relatives, such as Neanderthals and Homo erectus. Nicknamed "Rosa" after one of her discoverers , the fossil includes part of the upper jaw, cheek and eye from an adult, and dates to between 1.1 and 1.4 million years ago. As such, she represents the oldest known partial face of a hominin from western Europe.
Rosa is also a crucial piece of the puzzle explaining how and when humans first entered western Europe - and which species of hominin made those pioneering journeys.
Hominins evolved in Africa. The first species to occupy multiple continents was Homo erectus, and the first fossil evidence we have of them beyond Africa comes from Dmanisi in Georgia . These fossils are around 1.8 million years old. However, stone tools from Grăunceanu (Romania) indicate that hominins had expanded further north even earlier than the Dmanisi finds - 1.95 million years ago.
However, fossils from western Europe remain conspicuously absent until 1.4 million years ago. By contrast, we have more evidence of hominins moving into Asia during this time. They had reached Indonesia by 1.6 million years and descendants of these populations seem to have survived there until relatively recently . Early fossils from Asia are also more numerous and more complete, while their European counterparts are limited to an isolated tooth, a fragment of jaw and a partial skull cap.
Despite being just a small part of the face, Rosa provides key insights into these elusive early European populations. The researchers compared Rosa's facial features to Homo erectus fossils from Africa, Indonesia and Dmanisi. They also examined Rosa's similarities to Homo antecessor , a later European species from Gran Dolina, a site close to Sima del Elefante.
The evidence of settlement at Gran Dolina has been dated to about 860,000 years ago. While Rosa shares her delicate build with Homo antecessor, overall she has more affinities with the Homo erectus fossils - although not enough to confidently place her within this group.
Rosa may therefore provide support for a hypothesis that the occupation of Europe by hominins was discontinuous, at least for the first million or so years. This means that hominins settled there, then went locally extinct and were replaced by other groups of hominins later on.
Our closest relatives were not able to survive in Europe over long periods of time until much later. But why might that be? What made Europe harder to successfully inhabit than Asia? To begin to answer such questions, we have to combine the evidence from Rosa with what we already know about early human forays beyond their ancestral home continent of Africa.
Smaller brains, longer legs
The Dmanisi hominins are notable for their relatively small brains and basic tools. This challenged the idea that advanced tools and large brains were necessary for expansion beyond Africa. The tools from Grăunceanu are also relatively basic, despite the temperate and seasonal climate their makers would have experienced.
The Dmanisi hominins also have relatively long legs, which would have allowed them to move more efficiently over long distances. Perhaps, then, efficient movement, rather than brain size or technology, was the driving factor allowing the initial expansion. But did the basic stone technology used by early Europeans prevent their long term occupation of the continent?
It is likely that we will, in time, find even earlier fossils from western Europe. Further fossils from Sima del Elefante could reveal how variable Rosa's group was, and enable us to either place her within an existing species, or create a new one.
But, given the sparse information we have for now, the differences between Rosa, the Dmanisi hominins, and Homo antecessor fit within a model of short-term expansions into western Europe. These expansions were probably followed by a retreat of hominin populations into so-called refugia (locations where the environment and climate were more stable), as well as extinctions of local populations. This would have been driven by changing climatic conditions. For now, which and how many species ventured west into Europe is still unknown.
Much else also remains unknown. Did early western Europeans survive long enough to give rise to later species such as Homo antecessor? And how was Homo antecessor related to later European species? The European fossil record becomes more continuous from around 600,000 years ago, first with the appearance of a hominin species called Homo heidelbergensis, and then with the appearance of early Neanderthals (Homo neanderthalensis). In fact, these two species appear to have coexisted in Europe for some time.
Later Europeans were also able to venture further north, with evidence of footprints of a mystery hominin at Happisburgh in the UK by 900,000 years ago. Nevertheless, as with Rosa's species and Homo antecessor, the Neanderthals and Homo heidelbergensis eventually went extinct - along with all other species of humans globally, except our own.
The changing climate and northern latitudes of western Europe presented a clear challenge for earlier hominins. As Europe's climate continues to change, will Homo sapiens be the first hominin capable of long term survival here?
Suzy White receives funding from the Leverhulme Trust, and has previously received funding from the Arts and Humanities Research Council.
