Taxonomy, taphonomy and palaeoenvironment of hominid and non-hominid primates from the Jacovec Cavern, Sterkfontein

摘要

Results of a detailed taxonomic, taphonomic and palaeoenvironmental study of fossil primates from the Jacovec Cavern are presented. Six primate species: Australopithecus sp., Parapapio broomi, Parapapio jonesi, Papio izodi, Colobus sp. and a taxonomically indeterminate cercopithecoid have been recovered. A minimum of 19 individuals, comprising at least 28% of the total number of macro-mammalian individuals from this infill, were identified. The assemblage is characterized by low frequencies of vertebrae, an absence of antimeric sets of bone and a paucity of carnivore-modified bone. Data obtained from skeletal element representation, bone modification, in comparison with actualistic data from carnivore-primate carcass ravaging indicates that the assemblage is similar to a carnivore refuse assemblage, characterized by high frequencies of scapula, humeri, radius, ulna, and femora, and low frequencies of phalanges. However, the very low frequencies of craniodental elements departs from an expected carnivore refuse assemblage which has not been subjected to postdepositional processes. This further suggests that consumption of the primate individuals took place outside the cave, and that either one or a combination of carnivore species preyed upon the primates, or that a species not yet identified was responsible. In conjunction with the absence of near complete skeletons and/or antimeric sets of bone, the skeletal elements represented suggest that the cave did not act as a death trap. Cave sediment analyses show that the breccia in the cave is formed of conglomerates of sediments washed in from the ground above the cave. It is here suggested that, in addition to other processes, water may have been responsible for sorting the bones and carrying at least some of them into the cave. An attempt at palaeoenvironmental reconstruction suggests a mosaic of open grassland and tropical forest equivalent to today's equatorial forest in the Democratic Republic of Congo, and similar to that suggested for the contemporary infill of Sterkfontein Member 2.