title: Further morphological evidence on South African earliest Homo lower postcanine dentition: Enamel thickness and enamel dentine junction.
abstract: The appearance of the earliest members of the genus Homo in South Africa represents a key event in human evolution. Although enamel thickness and enamel dentine junction (EDJ) morphology preserve important information about hominin systematics and dietary adaptation, these features have not been sufficiently studied with regard to early Homo. We used micro-CT to compare enamel thickness and EDJ morphology among the mandibular postcanine dentitions of South African early hominins (N = 30) and extant Homo sapiens (N = 26), with special reference to early members of the genus Homo. We found that South African early Homo shows a similar enamel thickness distribution pattern to modern humans, although three-dimensional average and relative enamel thicknesses do not distinguish australopiths, early Homo, and modern humans particularly well. Based on enamel thickness distributions, our study suggests that a dietary shift occurred between australopiths and the origin of the Homo lineage. We also observed that South African early Homo postcanine EDJ combined primitive traits seen in australopith molars with derived features observed in modern human premolars. Our results confirm that some dental morphological patterns in later Homo actually occurred early in the Homo lineage, and highlight the taxonomic value of premolar EDJ morphology in hominin species.
authors.affiliation: Computer-Assisted Palaeoanthropology Team, UMR 5288 CNRS-Université de Toulouse (Paul Sabatier), 37 Allées Jules Guesde, 31000 Toulouse, France; Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 100044 Beijing, China. Electronic address: lei.pan@univ-tlse3.fr.
authors.forename: Lei
authors.initials: L
authors.lastname: Pan
authors.affiliation: Computer-Assisted Palaeoanthropology Team, UMR 5288 CNRS-Université de Toulouse (Paul Sabatier), 37 Allées Jules Guesde, 31000 Toulouse, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Dumoncel
authors.affiliation: South African Nuclear Energy Corporation, Pelindaba, North West Province, South Africa.
authors.forename: Frikkie
authors.initials: F
authors.lastname: de Beer
authors.affiliation: South African Nuclear Energy Corporation, Pelindaba, North West Province, South Africa.
authors.forename: Jakobus
authors.initials: J
authors.lastname: Hoffman
authors.affiliation: Evolutionary Studies Institute, University of the Witwatersrand, PO WITS, Johannesburg 2050, South Africa.
authors.forename: John Francis
authors.initials: JF
authors.lastname: Thackeray
authors.affiliation: Centre Inter-universitaire de Recherche et d'Ingénierie des Matériaux, UMR 5085 CNRS-Université de Toulouse (Paul Sabatier), 118 route de Narbonne, 31062 Toulouse Cedex 9, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Duployer
authors.affiliation: Centre Inter-universitaire de Recherche et d'Ingénierie des Matériaux, UMR 5085 CNRS-Université de Toulouse (Paul Sabatier), 118 route de Narbonne, 31062 Toulouse Cedex 9, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Tenailleau
authors.affiliation: Computer-Assisted Palaeoanthropology Team, UMR 5288 CNRS-Université de Toulouse (Paul Sabatier), 37 Allées Jules Guesde, 31000 Toulouse, France; Evolutionary Studies Institute, University of the Witwatersrand, PO WITS, Johannesburg 2050, South Africa.
authors.forename: José
authors.initials: J
authors.lastname: Braga
mesh_terms: D000818:Animals; D001641:Bicuspid / Q000033:anatomy & histology*; D005075:Biological Evolution; D003743:Dental Enamel / Q000033:anatomy & histology; D003804:Dentin / Q000033:anatomy & histology; D005580:Fossils / Q000033:anatomy & histology*; D015186:Hominidae / Q000033:anatomy & histology*; D006801:Humans; D008963:Molar / Q000033:anatomy & histology*; D013019:South Africa; D055114:X-Ray Microtomography
keywords: Australopiths; Dental evolution; Dietary adaptation; Geometric morphometric; Taxonomic discrimination