The diet of Homo antecessor

Abstract

The diet of the earliest inhabitants of Europe has been previously inferred from archaeological evidence. However, the effects of dietary preferences on teeth remain unknown. Here, we report a novel approach through quantitative analysis of buccal microwear on cheek teeth in well-documented Gran Dolina-TD6 Atapuerca (Burgos, Spain) hominins (≈0.8 million years ago), since microwear on non-working molar surfaces reflects the physical properties of chewed foodstuffs and long-term trends in dietary signals. Buccal-microwear was examined with scanning microscopy from high-resolution molar crown impression replicas. Scratch density and length (in micrometers) were measured at 100× magnification in well-preserved enamel facets, preferably under protoconid cusp tips. Results showed that early Atapuerca hominins show a higher abraded scratch pattern compared with Sima de los Huesos and Neanderthals hominins from Iberian Peninsula. The lack of evidence in the use of fire in the TD6 level indicated that non-thermal hard and brittle raw foods increased the abrasiveness of the diet. In basis to this unique dental microwear pattern found, we suggest that Homo antecessor was specialized in the ingestion of fracture-resistant foodstuffs such as Underground Storage Organs (USOs) and scavenged or hunted gritty meat resources. This mechanically-demanding dietary regimen would have required strong bite force production. The microwear density reduction in Middle Pleistocene populations suggest differences in food mechanical properties linked to more advanced tool technologies.