Scientists from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) are taking part in a comparative study, published in the journal PLOS ONE, regarding the dental tissue of the molars of Homo antecessor. Results suggest that some features of the structure of the molars in the Neanderthals were already found in these lower European Pleistocene hominins, who discovered at the TD6 level of the Gran Dolina site (Atapuerca, Burgos).
With the help of micro-computed tomography (mCT) and high-resolution images from CENIEH laboratories, the authors have managed to compare the internal structure, namely, enamel thickness, percentage of tissues and their distribution in the crown, of 17 molars of Homo antecessor with over 300 molars that belong to current populations and extinct species of the genus Homo from Africa, Asia and Europe.
“In comparison to the fossil records and modern humans, Neanderthals had a fine enamel, with a much more elevated proportion of dentin and a more dispersed distribution pattern”, asserts the lead author of this study, Laura Martín-Francés, of the University of Bordeaux, who is working with CENIEH's Dental Anthropology Group.
Homo antecessor molars had a thick enamel and therefore do not have this feature in common with Neanderthals. Nonetheless, the pattern of tissue distribution in molars resembles that of Neanderthals more than that of other hominins.
“Whereas the enamel in other hominins, including modern humans, usually concentrates on the cusps, in Homo antecessor and in Neanderthals the enamel distributes itself in a more peripheral way, concentrating at the base of the crown of the tooth”, explains Laura Martín Francés.
The Homo antecessor dental collection offers a unique opportunity for the study of the appearance of the “typical” Neanderthal structural pattern, given both its geographical location and its chronology, which is almost one million years.
“It is worth noting that the dental structural characterization of other mid and lower Pleistocene European hominins, as the Sima de los Huesos molar collection, will contribute to clarify the evolutionary stages that led to the characteristic dentition of the upper Pleistocene hominins”, Laura Martin-French states.
Deep roots in Europe
The conclusions of the present article are consistent with another study recently published by the CENIEH Dental Anthropology Group in the journal PLOS ONE on the oldest human remains in Italy.
As in the chronology of the Sima de los Huesos fossils, the teeth found in the Italian sites of Fontana Ranuccio and Visogliano have a strongly Neanderthal semblance. “Taken as a whole, it signifies that the Neanderthals have profound roots in Europe”, explains researcher Maria Martinón-Torres, head of CENIEH, “and that the Neanderthal dentition was thoroughly consolidated half a million years ago.”