On Saturday 22 June 2024, twenty-one members of the Northern Branch enjoyed a captivating visit to the Drimolen palaeocave system in the Lion and Rhino Nature Reserve at the Cradle of Humankind. We were warmly welcomed by Dr Stephany Caruana (nee Baker) of the Palaeo- Research Institute of UJ. She is the current Director and co-permit holder of this site with Dr Andy Herries of Latrobe University in Melbourne. Despite her hectic schedule – our visit coincided with the annual field trip of students from Latrobe University and from Washington University at St Louis – she kept us spellbound for almost two hours. 

Our first stop was at the Main Quarry. Dr André Keyser, a palaeontologist and geologist with the Palaeoanthropology Unit for Research and Exploration at Wits University, excavated it from 1992 until his death in 2010. The existence of late-19th century lime mining pits, including an unusual oval- shaped kiln, alerted him to the possible presence of fossilised remains at this site. Quicklime played a pivotal role in many gold mining processes, and the underground dolomitic caverns were therefore mined for their lime contents. Such caverns often also often contain the fossilised remains of fauna, flora and hominins. Keyser’s instincts that the site would be worth excavating were spot on. The Main Quarry consists of one cave chamber exposed through many years of erosion and subsequent blasting and quarrying by lime miners. Somewhat surprisingly, mining activities have aided palaeoanthropological research by exposing depositional sequencing throughout the site. In 1994 Keyser discovered a pair of crania, respectively designated DNH 7 and DNH 8.  DNH 7 was subsequently identified as a female juvenile of the species Paranthropus robustus. Her cranium is significantly smaller than that of the male counterpart, DNH 8, but more importantly, it lacks the sagittal crest. This provided scientists with much-needed insight into the sexual diomorphism of the Paranthropus species. The sagittal crest is a prominent ridge of bone that projects upwards from the cranial vault along the midline, most often seen in adult male gorillas. Sexual diomorphism is the condition where sexes of the same species exhibit different structural features and characteristics. Numerous specimens of both Paranthropus and early Homo have since been discovered at the site. Overall, the fossils seem to be mainly deposited along the western rim of the cave wall.