Revisiting the context and geochronological ages of the Homo sapiens skeletal remains from Border Cave, South Africa

The Border Cave human remains have featured in discussions relating to the evolution and the behavior of Late Pleistocene Homo sapiens. Although there are seven specimens that have been held to emanate from its Middle Stone Age (MSA) deposits, the stratigraphic context (and thus the presumed antiquity) of most of them is open to question. Five were recovered ex situ; either from a large sediment dump produced by guano digging in 1940 (BC 1 cranium and BC 2 mandible) or from the collapsed wall of an old excavation (BC 6 humerus, BC 7 ulna, and BC 8 metatarsals). One specimen (BC 3 infant burial) was excavated in 1942 from a grave that had been dug into a MSA layer, and another (BC 5 mandible) was dislodged from a MSA layer in the course of cleaning the excavation face for sediment sampling. Among these seven specimens, only BC 6 and BC 7 exhibit the fragmentary preservation together with chemical signatures consistent with MSA faunal elements from the site. Moreover, these are the only two specimens from Border Cave that share primitive morphology with homologues from other MSA/Middle Paleolithic sites. It is not possible to determine the stratigraphic placement of BC 1, BC 2 and BC 8 with any degree of certainty, although the state of preservation and morphology of BC 1 suggest that its origin is in the Later Stone Age (LSA) rather than the MSA. The BC 3 grave was dug into MSA levels and several workers have argued that the remarkable state of preservation of the infant skeleton and possibly its chemical signature suggests that derivation from the ELSA cannot be ruled out. BC 5 is arguably the only specimen from Border Cave recovered from in situ MSA deposits. Although it was found immediately adjacent to a feature considered to possibly represent a burial, the sediments from which BC 5 was recovered were reasonably deep in the sequence, rendering derivation from the LSA unlikely.