title: The first hominin from the early Pleistocene paleocave of Haasgat, South Africa.
abstract: Haasgat is a primate-rich fossil locality in the northeastern part of the Fossil Hominid Sites of South Africa UNESCO World Heritage Site. Here we report the first hominin identified from Haasgat, a partial maxillary molar (HGT 500), that was recovered from an ex situ calcified sediment block sampled from the locality. The in situ fossil bearing deposits of the Haasgat paleokarstic deposits are estimated to date to slightly older than 1.95 Ma based on magnetobiostratigraphy. This places the hominin specimen at a critical time period in South Africa that marks the last occurrence of Australopithecus around 1.98 Ma and the first evidence of Paranthropus and Homo in the region between ∼2.0 and 1.8 Ma. A comprehensive morphological evaluation of the Haasgat hominin molar was conducted against the current South African catalogue of hominin dental remains and imaging analyses using micro-CT, electron and confocal microscopy. The preserved occlusal morphology is most similar to Australopithecus africanus or early Homo specimens but different from Paranthropus. Occlusal linear enamel thickness measured from micro-CT scans provides an average of ∼2.0 mm consistent with Australopithecus and early Homo. Analysis of the enamel microstructure suggests an estimated periodicity of 7-9 days. Hunter-Schreger bands appear long and straight as in some Paranthropus, but contrast with this genus in the short shape of the striae of Retzius. Taken together, these data suggests that the maxillary fragment recovered from Haasgat best fits within the Australopithecus-early Homo hypodigms to the exclusion of the genus Paranthropus. At ∼1.95 Ma this specimen would either represent another example of late occurring Australopithecus or one of the earliest examples of Homo in the region. While the identification of this first hominin specimen from Haasgat is not unexpected given the composition of other South African penecontemporaneous site deposits, it represents one of the few hominin localities in the topographically-distinct northern World Heritage Site. When coupled with the substantial differences in the mammalian faunal communities between the northern localities (e.g., Haasgat, Gondolin) and well-sampled Bloubank Valley sites (e.g., Sterkfontein, Swartkrans, Kromdraai), the recovery of the HGT 500 specimen highlights the potential for further research at the Haasgat locality for understanding the distribution and interactions of hominin populations across the landscape, ecosystems and fossil mammalian communities of early Pleistocene South Africa. Such contextual data from sites like Haasgat is critical for understanding the transition in hominin representation at ∼2 Ma sites in the region from Australopithecus to Paranthropus and early Homo.
authors.affiliation: The Australian Archaeomagnetism Laboratory, Department of Archaeology and History, La Trobe University, Bundoora, Victoria, Australia; Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia.
authors.forename: A B
authors.initials: AB
authors.lastname: Leece
authors.affiliation: Department of Biomedical Sciences, Grand Valley State University , Allendale, MI , United States of America.
authors.forename: Anthony D T
authors.initials: AD
authors.lastname: Kegley
authors.affiliation: Department of Basic Science and Craniofacial Biology, New York University , New York, NY , United States of America.
authors.forename: Rodrigo S
authors.initials: RS
authors.lastname: Lacruz
authors.affiliation: The Australian Archaeomagnetism Laboratory, Department of Archaeology and History, La Trobe University, Bundoora, Victoria, Australia; Centre for Anthropological Research, University of Johannesburg, Johannesburg, Gauteng, South Africa.
authors.forename: Andy I R
authors.initials: AI
authors.lastname: Herries
authors.affiliation: School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand , Johannesburg , South Africa.
authors.forename: Jason
authors.initials: J
authors.lastname: Hemingway
authors.affiliation: Plio-Pleistocene Section, Department of Vertebrates, Ditsong National Museum of Natural History , Pretoria , South Africa.
authors.forename: Lazarus
authors.initials: L
authors.lastname: Kgasi
authors.affiliation: Plio-Pleistocene Section, Department of Vertebrates, Ditsong National Museum of Natural History , Pretoria , South Africa.
authors.forename: Stephany
authors.initials: S
authors.lastname: Potze
authors.affiliation: Department of Anatomy and Developmental Biology, Monash University , Melbourne, Victoria , Australia.
authors.forename: Justin W
authors.initials: JW
authors.lastname: Adams
keywords: Australopithecus; Enamel microstructure; Homo; Paleokarst; Paleomagnetism; Paranthropus