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Specimens of Australopithecus sediba from the site of Malapa, South Africa (dating from approximately 2 million years (Myr) ago)1 present a mix of primitive and derived traits that align the taxon with other Australopithecus species and with early Homo2. Although much of the available cranial and postcranial material of Au. sediba has been described3-6, 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 C^sub 3^ 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 C^sub 3^ foods in preference to widely available C^sub 4^ resources. The inferred consumption of C^sub 3^ 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.
Early hominin diet is central to the study of human origins. Dietary data come from a variety of sources that provide different information about the foods consumed. Carbon isotopes indicate whether an animal ate C3 resources (for example, trees, shrubs, some herbs, and animals eating these plants), C4 resources (for example, most tropical grasses, sedges, and animals eating these plants) or a combination of these7. Chimpanzees consume C3 plants such as fruits and leaves even when C4 grasses are abundant8,9. By contrast, isotopic evidence indicates that Australopithecus, Paranthropus and early Homo consumed variable amounts of C4 foods, but their diets included more C4 foods than the diets of modern chimpanzees, indicating that they probably used their environments in different ways than do living apes10-12. Dental microwear provides information about the fracture properties of foods consumed shortly before the death of an animal13. Previous studies of Australopithecus africanus, and particularly of Australopithecus afarensis and Paranthropus boisei, suggest limited variance in food hardness, whereas Homo erectus and Paranthropus robustus have greater variance in texture complexity consistent with a more...