Could the Rising Star hominins represent relict australopiths?

Abstract Following ten years of excavation, the Rising Star cave system (Gauteng Province, South Africa) yielded a large assemblage of skeletal and dental remains attributed to the extinct species Homo naledi. The bones and teeth show a mixture of features found in the australopith and/or early Homo, together with autapomorphic traits. The Rising Star hominins lived toward the end of the Middle Pleistocene, at a time when it is commonly assumed that among hominin genera, only Homo existed, while the australopiths were long extinct. However, the African fossil record for this time period is extremely scarce, with only a few Middle Pleistocene fossils available for all of the continent. The morphological evidence is analysed here to re-evaluate the taxonomy of the Rising Star hominins and to eventually explore different evolutionary scenarios.