Some of the secrets of early hominid evolution might have been revealed thanks to teeth discovered in Southern Europe. Dental samples uncovered in Spain and Italy, are helping researchers understand when features typical of Neanderthals evolved.
Neanderthals had very thin enamel compared to other hominins. Researchers looked for this characteristic in hominin ancestors and discovered new evidence suggesting where and when certain features evolved. These findings, published in two studies on PLOS ONE add to the growing complexity of human evolution during the early and middle Pleistocene period.
The first study focuses on teeth belonging to Homo antecessor, a proposed archaic human present in western Europe between 1.2 and 0.8 million years ago. Researchers looked at 17 molars using CT scans and discovered that while H. antecessor didn’t have the same thin enamel as Neanderthals, the overall distribution of tissues was closer than to other Homo species.
"The Early Pleistocene species, Homo antecessor (Atapuerca, Spain) shares the same molar enamel thickness with most hominins, including Homo sapiens. However, as early as 900,000 ago, Homo antecessor shows a few structural characteristics that are absent in the rest of the hominin species and will become the typical Neanderthal configuration," lead author Laura Martín-Francés of the University of Bordeaux, said in a statement.
The second study focused on teeth from roughly 450,000 years ago discovered in two sites in Italy, Fontana Ranuccio near Rome and near Trieste called Visogliano. The analysis showed teeth that are very similar to Neanderthals a few tens of thousands of years before the first Neanderthals walked the Earth. These teeth are not only different from our own, they are also different from other contemporary species of hominins. There must have been several lineages in Eurasia at the time.
"The remains from Fontana Ranuccio and Visogliano represent among the oldest human fossil remains testifying to a peopling phase of the Italian Peninsula," leader of the second study Clément Zanolli of the Université Toulouse III Paul Sabatier explained. "Our analyses of the tooth internal structural organization reveals a Neanderthal-like signature, also resembling the condition shown by the contemporary assemblage from Atapuerca Sima de los Huesos, indicating that an overall Neanderthal morphological dental template was preconfigured in Western Europe at least 430,000 to 450,000 ago."
These findings suggest that, in the past, researchers may have underestimated just how much variety was happening in the human evolutionary path about 500,000 years ago.