Search

The past 5 million years mark a global change from the warmer, more stable climate of the Pliocene to the initiation of glacial–interglacial cycles during the Pleistocene. Marine core sediment records located off the coast of southwestern Africa indicate aridification and intensified upwelling in the Benguela Current over the Pliocene and Pleistocene. However, few terrestrial records document environmental change in southwestern Africa over this time interval. Here we synthesize new and published carbon and oxygen isotope data of the teeth from large mammals (> 6 kg) at Langebaanweg (~ 5 million years ago, Ma), Elandsfontein (1.0–0.6 Ma), and Hoedjiespunt (0.35–0.20 Ma), to evaluate environmental change in southwestern Africa between the Pliocene and Pleistocene. The majority of browsing and grazing herbivores from these sites yield enamel δ 13 C values within the range expected for animals with a pure C 3 diet, however some taxa have enamel δ 13 C values that suggest the presence of small amounts C 4 grasses at times during the Pleistocene. Considering that significant amounts of C 4 grasses require a warm growing season, these results indicate that the winter rainfall zone, characteristic of the region today, could have been in place for the past 5 million years. The average δ 18 O value of the herbivore teeth increases ~ 4.4‰ between Langebaanweg and Elandsfontein for all taxa except suids. This increase may solely be a function of a change in hydrology between the fluvial system at Langebaanweg and the spring-fed environments at Elandsfontein, or a combination of factors that include depositional context, regional circulation and global climate. However, an increase in regional aridity or global cooling between the early Pliocene and mid-Pleistocene cannot explain the entire increase in enamel δ 18 O values. Spring-fed environments like those at Elandsfontein may have provided critical resources for mammalian fauna in the mid-Pleistocene within an increasingly arid southwestern Africa ecosystem. [ABSTRACT FROM AUTHOR]

Several large-bodied hominin and nonhuman primates have coexisted in the Cradle of Humankind in South Africa during the Early Pleistocene. Previous paleoenvironmental studies regarding the Plio-Pleistocene of South Africa have focused heavily on mammal assemblages. Here, we conducted a comprehensive taxonomic analysis of the fossil bird remains from Cooper's D, the most fossiliferous locality of the hominin-bearing Cooper's Cave complex in South Africa. Our taxonomic evaluation of 505 remains reveals the presence of 23 bird taxa, two of which are extinct and already reported from the nearby fossil locality of Kromdraai. The taxonomically diverse bird assemblage is dominated by Francolinus sp. and other species associated with open grassland habitats, followed by rock-dwelling species, including Tyto cf. alba and the extinct Corvus bragai , and by woodland species such as Agapornis sp., Accipiter melanoleucos , and the extinct Glaucidium ireneae. The occurrence of these taxa and their respective proportions in the assemblage, in terms of both numbers of bones and individuals, point to the presence of extensive open grassland and/or savannah with rocky outcrops and woodland. These findings corroborate previous analyses of mammals from Cooper's D, with the exception of aquatic species, which are rare in the bird assemblage. Comparison with older deposits from Kromdraai confirms the definitive establishment of open habitats in the Cradle of Humankind during the Early Pleistocene following a transition from woodier habitats during the Late Pliocene. This study constitutes a further step in investigating the fossil bird diversity in the Cradle of Humankind during the Plio-Pleistocene. Our results add to the larger body of work using avian fossils for paleoenvironmental reconstructions in Africa and support the utility of birds as paleoenvironmental proxies. Similar future studies will refine our understanding of the paleoenvironments and landscape transformation during the Plio-Pleistocene, a critical timeframe for hominin evolution in southern Africa. [ABSTRACT FROM AUTHOR]