Fossil micromammals and the palaeoenvironments of the Paranthropus robustus site of Cooper's Cave

The Cradle of Humankind (Gauteng, South Africa) provides an important fossil record of the evolutionary history of PlioPleistocene hominins. Cooper's Cave deposits have yielded a rich fossil faunal assemblage, as well as six remains attributed to Paranthropus robustus. This study provides the first taxonomic, taphonomic and palaeoecological description of the micromammal material from the 1.4 Ma assemblage of Cooper's D. The taphonomic signature of the assemblage indicates an accumulation by tytonid owls (probably Tyto alba) and advanced postdepositional disturbance probably related to trampling by the occupants of the cave, sorting of the bones along slope, and burying. The taxonomic analysis undertaken here at genus level describes at least 22 taxa of small mammals, including one extinct genus Proodontomys. This assemblage is dominated by Mystromys and Otomys, two rodent genera adapted to grassland habitats which are among the most common among pliopleistocene micromammal faunas from the region. The palaeoecological analysis suggests an open landscape with a predominance of grassland and savanna vegetation, and the proximity of rocky outcrops and a perennial river. These results support previous indications of a shift in the African climate and vegetation towards more open habitats during the Early Pleistocene.