There is much debate on the dietary adaptations of the robust hominin lineages during the Pliocene-Pleistocene transition. It has been argued that the shift from C3 to C4 ecosystems in Africa was the main factor responsible for the robust dental and facial anatomical adaptations of Paranthropus taxa, which might be indicative of the consumption of fibrous, abrasive plant foods in open environments. However, occlusal dental microwear data fail to provide evidence of such dietary adaptations and are not consistent with isotopic evidence that supports greater C4 food intake for the robust clades than for the gracile australopithecines. We provide evidence from buccal dental microwear data that supports softer dietary habits than expected for P. aethiopicus and P. boisei based both on masticatory apomorphies and isotopic analyses. On one hand, striation densities on the buccal enamel surfaces of paranthropines teeth are low, resembling those of H. habilis and clearly differing from those observed on H. ergaster, which display higher scratch densities indicative of the consumption of a wide assortment of highly abrasive foodstuffs. Buccal dental microwear patterns are consistent with those previously described for occlusal enamel surfaces, suggesting that Paranthropus consumed much softer diets than previously presumed and thus calling into question a strict interpretation of isotopic evidence. On the other hand, the significantly high buccal scratch densities observed in the H. ergaster specimens are not consistent with a highly specialized, mostly carnivorous diet; instead, they support the consumption of a wide range of highly abrasive food items.

Despite the scarcity of fossil specimens of Theropithecus oswaldi in Eurasia, its presence out of Africa attests to the great dispersal of this Papionini genus during the Early Pleistocene. In the present study, we analyze the buccal dental microwear of T. oswaldi (T. o. leakeyi) fossil specimens from Cueva Victoria (Southeastern Spain). This analysis is the first characterization of the feeding ecology of T. oswaldi in Europe. The buccal microwear pattern of the molar and premolar teeth of T. oswaldi from Cueva Victoria shows great similarities to that observed for the extant frugivorous forest-dwelling Mandrillus sphinx and mangabeys (Cercocebus sp.)dboth species adapted to durophagous dietary habitsdwhile significantly differed from that observed for the gramnivorous Theropithecus gelada. These results suggest that T. oswaldi from Cueva Victoria could have exploited both hard-shelled fruits or seeds and succulent fruits from open and forested Mediterranean ecosystems.

Objectives: This study compares ISO (ISO/FDIS 25178) roughness parameters, calculated from three-dimensional (3D) molar buccal microtexture surfaces, among African Cercopithecoidea primates with different diets. Materials and Methods:We examined 98 lower second molars from seven African Cercopithecoidea species with diverse dietary regimes and habitat exploitation. Buccal dental surfaces were analyzed using a Sensofar Plu Neox laser scanning confocal microscope. Thirty-eight, areal surface texture parameters were extracted (Mountain 7 ® software). Uni-and multivariate statistics were used to obtain diet-related patterns of buccal-microwear textures and feeding ecology to differentiate between species.Results: Buccal-dental 3D texture parameters discriminate between Cercopithecoidea diets. Analysis of variance (ANOVA) revealed significant variation in microwear texture between forest-adapted Mandrillus sphinx, which showed coarse flat features, and grassland forager Theropithecus gelada, whose buccal surfaces were characterized by a high density of thin features. Buccal-microwear textures of folivorous species (Colobus polykomos) were related to a lower density of thicker surface indentations in comparison to Papio anubis and Cercocebus atys which are adapted to the consumption of tough and hard foods. The limited interspecific variation in the buccalmicrowear textures of savanna dwellers (Chlorocebus pygerythrus and Chlorocebus aethiops) probably reflects similarities in their foraging diets.Discussion: Significant variations between-species demonstrate that 3D microwear ISO roughness parameters applied to buccal enamel surfaces can distinguish between the diets of Cercopithecoidea.