Paul Sandberg

The diet of Australopithecus sediba

Specimens of Australopithecus sediba from the site of Malapa, South Africa (dating from approximately 2 million years (Myr) ago) present a mix of primitive and derived traits that align the taxon with other Australopithecus species and with early Homo. Although much of the available cranial and postcranial material of Au. sediba has been described, its feeding ecology has not been investigated. Here we present results from the first extraction of plant phytoliths from dental calculus of an early hominin. We also consider stable carbon isotope and dental microwear texture data for Au. sediba in light of new palaeoenvironmental evidence. The two individuals examined consumed an almost exclusive C3 diet that probably included harder foods, and both dicotyledons (for example, tree leaves, fruits, wood and bark) and monocotyledons (for example, grasses and sedges). Like Ardipithecus ramidus (approximately 4.4 Myr ago) and modern savanna chimpanzees, Au. sediba consumed C3 foods in preference to widely available C4 resources. The inferred consumption of C3 monocotyledons, and wood or bark, increases the known variety of early hominin foods. The overall dietary pattern of these two individuals contrasts with available data for other hominins in the region and elsewhere.

Intra-Tooth Stable Isotope Analysis of Dentine: A Step Toward Addressing Selective Mortality in the Reconstruction of Life History in the Archaeological Record

Intra-tooth stable isotope analysis of dentine provides a more sensitive means to examine infant and childhood life history in the past than conventional cross-sectional analyses that rely on age-at-death. In addition, reconstructions of early diet and life history using an intra-tooth approach circumvent potential problems associated with mortality bias, which may operate strongly during infancy and childhood. We present new intra-tooth stable carbon and nitrogen isotope profiles in dentine collagen of early forming permanent teeth in a sample of adults from the Medieval Nubian site of Kulubnarti. We interpret the profiles in terms of weaning behavior and dietary history, and we compare profiles generated from first molars and canines to explore the degree to which these tooth types correspond. We then compare the profiles to the occurrence of linear enamel hypoplasia to assess the relationship between the timing of the weaning process and stress events. Finally, we compare the longitudinal profiles to cross-sectional stable isotope data obtained from rib collagen to investigate how life histories might differ between those that survived into adulthood and those that did not. Results suggest that canine and first molar profiles are in broad agreement, that hypoplastic stress events occurred during rather than before or after the weaning process in our sample, and that survivors appear to have weaned earlier than the average non-survivor. We suggest that this approach may be useful for addressing the effects of selective mortality on reconstructions of early life history and the relationship between early life history and morbidity.

Stable Isotope Analysis in Primatology: A Critical Review

Stable isotope analysis has become an important tool in ecology over the last 25 years. A wealth of ecological information is stored in animal tissues in the relative abundances of the stable isotopes of several elements, particularly carbon and nitrogen, because these isotopes navigate through ecological processes in predictable ways. Stable carbon and nitrogen isotopes have been measured in most primate taxonomic groups and have yielded information about dietary content, dietary variability, and habitat use. Stable isotopes have recently proven useful for addressing more fine‐grained questions about niche dynamics and anthropogenic effects on feeding ecology. Here, we discuss stable carbon and nitrogen isotope systematics and critically review the published stable carbon and nitrogen isotope data for modern primates with a focus on the problems and prospects for future stable isotope applications in primatology. Am. J. Primatol. 74:969‐989, 2012.