Marine Cazenave1,2, Christopher Dean3,4, Clément Zanolli5, Anna C Oettlé2,6, Jakobus Hoffman7, Mirriam Tawane8, Francis Thackeray9, Roberto Macchiarelli10,11. 1. Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK. 2. Department of Anatomy and Histology, Sefako Makgatho Health Sciences University, Ga-Rankuwa, Pretoria, South Africa. 3. Department of Earth Sciences, Natural History Museum, London, UK. 4. Department of Cell and Developmental Biology, University College London, London, UK. 5. UMR 5199 CNRS, Université de Bordeaux, Bordeaux, France. 6. Department of Anatomy, University of Pretoria, Pretoria, South Africa. 7. South African Nuclear Energy Corporation SOC, Ltd., Pelindaba, South Africa. 8. Ditsong National Museum of Natural History, Pretoria, South Africa. 9. Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa. 10. UMR 7194 CNRS, Muséum national d'Histoire naturelle, Musée de l'Homme, Paris, France. 11. Unité de Formation Géosciences, Université de Poitiers, Poitiers, France.
Abstract
OBJECTIVES: The Pleistocene taxon Paranthropus robustus was established in 1938 following the discovery at Kromdraai B, South Africa, of the partial cranium TM 1517a and associated mandible TM 1517b. Shortly thereafter, a distal humerus (TM 1517g), a proximal ulna (TM 1517e), and a distal hallucial phalanx (TM 1517k) were collected nearby at the site, and were considered to be associated with the holotype. TM 1517a-b represents an immature individual; however, no analysis of the potentially associated postcranial elements has investigated the presence of any endostructural remnant of recent epiphyseal closure. This study aims at tentatively detecting such traces in the three postcranial specimens from Kromdraai B. MATERIALS AND METHODS: By using μXCT techniques, we assessed the developmental stage of the TM 1517b's C-M3 roots and investigated the inner structure of TM 1517g, TM 1517e, and TM 1517k. RESULTS: The M2 shows incompletely closed root apices and the M3 a half-completed root formation stage. The distal humerus was likely completely fused, while the proximal ulna and the distal hallucial phalanx preserve endosteal traces of the diaphyseo-epiphyseal fusion process. DISCUSSION: In the hominin fossil record, there are few unambiguously associated craniodental and postcranial remains sampling immature individuals, an essential condition for assessing the taxon-specific maturational patterns. Our findings corroborate the original association of the craniodental and postcranial remains representing the P. robustus type specimen. As with other Plio-Pleistocene hominins, the odonto-postcranial maturational pattern of TM 1517 more closely fits an African great ape rather than the extant human pattern.
OBJECTIVES: The Pleistocene taxon Paranthropus robustus was established in 1938 following the discovery at Kromdraai B, South Africa, of the partial cranium TM 1517a and associated mandible TM 1517b. Shortly thereafter, a distal humerus (TM 1517g), a proximal ulna (TM 1517e), and a distal hallucial phalanx (TM 1517k) were collected nearby at the site, and were considered to be associated with the holotype. TM 1517a-b represents an immature individual; however, no analysis of the potentially associated postcranial elements has investigated the presence of any endostructural remnant of recent epiphyseal closure. This study aims at tentatively detecting such traces in the three postcranial specimens from Kromdraai B. MATERIALS AND METHODS: By using μXCT techniques, we assessed the developmental stage of the TM 1517b's C-M3 roots and investigated the inner structure of TM 1517g, TM 1517e, and TM 1517k. RESULTS: The M2 shows incompletely closed root apices and the M3 a half-completed root formation stage. The distal humerus was likely completely fused, while the proximal ulna and the distal hallucial phalanx preserve endosteal traces of the diaphyseo-epiphyseal fusion process. DISCUSSION: In the hominin fossil record, there are few unambiguously associated craniodental and postcranial remains sampling immature individuals, an essential condition for assessing the taxon-specific maturational patterns. Our findings corroborate the original association of the craniodental and postcranial remains representing the P. robustus type specimen. As with other Plio-Pleistocene hominins, the odonto-postcranial maturational pattern of TM 1517 more closely fits an African great ape rather than the extant human pattern.
Authors: Anjali M Prabhat; Catherine K Miller; Thomas Cody Prang; Jeffrey Spear; Scott A Williams; Jeremy M DeSilva Journal: Elife Date: 2021-05-12 Impact factor: 8.140