Linear enamel hypoplasia in Homonaledi reappraised in light of new Retzius periodicities.

Objectives: Among low‐latitude apes, developmental defects of enamel often recur twice yearly, linkable to environmental cycles. Surprisingly, teeth of Homonaledi from Rising Star in South Africa (241–335 kya), a higher latitude site with today a single rainy season, also exhibit bimodally distribut...

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Publicado en:American Journal of Biological Anthropology Vol. 184; no. 3; pp. 1 - 19
Autores principales: Skinner, Mark Fretson, Delezene, Lucas Kyle, Skinner, Matthew M., Mahoney, Patrick
Formato: Artículo
Publicado: Wiley-Blackwell Jul2024
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Acceso en línea:Ver este registro en EBSCOhost
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      dt: Jul2024
      vid: 184
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      pub: Wiley-Blackwell
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        10.1002/ajpa.24927
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        atl: Linear enamel hypoplasia in Homonaledi reappraised in light of new Retzius periodicities.
      aug:
        au:
          Skinner, Mark Fretson
          Delezene, Lucas Kyle
          Skinner, Matthew M.
          Mahoney, Patrick
        affil:
          Department of Archaeology, Simon Fraser University, Burnaby British Columbia,, Canada
          Department of Anthropology, University of Arkansas, Fayetteville Arkansas,, USA
          Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
          Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
          Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
      su:
        South Africa
        Ameloblasts
        Dental enamel
        Developmental defects of enamel
        Enamel & enameling
        Optical scanners
        Incisors
      sug:
        subj:
          South Africa
          Computer and peripheral equipment manufacturing
          Computer Terminal and Other Computer Peripheral Equipment Manufacturing
          Ameloblasts
          Dental enamel
          Developmental defects of enamel
          Enamel & enameling
          Optical scanners
          Incisors
      keyword:
        developmental stress
        Middle Pleistocene
        ontogeny
        Rising Star
        seasonality
        developmental stress
        Middle Pleistocene
        ontogeny
        Rising Star
        seasonality
      ab: Objectives: Among low‐latitude apes, developmental defects of enamel often recur twice yearly, linkable to environmental cycles. Surprisingly, teeth of Homonaledi from Rising Star in South Africa (241–335 kya), a higher latitude site with today a single rainy season, also exhibit bimodally distributed hypoplastic enamel defects, but with uncertain timing and etiology. Newly determined Retzius periodicities for enamel formation in this taxon enable a reconstruction of the temporal patterning of childhood stress. Methods: Using high resolution casts of 31 isolated anterior teeth from H. naledi, 82 enamel defects (linear enamel hypoplasia [LEH]) were identified. Seventeen teeth are assigned to three individuals. Perikymata in the occlusal wall of enamel furrows and between the onsets of successive LEH were visualized with scanning electron microscopy and counted. Defects were measured with an optical scanner. Conversion of perikymata counts to estimates of LEH duration and inter‐LEH interval draws upon Retzius periodicities of 9 and 11 days. Results: Anterior teeth record more than a year of developmental distress, expressed as two asymmetric intervals centered on 4.5 and 7.5 months bounded by three LEH. Durations, also, show bimodal distributions, lasting 3 or 12 weeks. Short duration LEH are more severe than long duration. Relative incisor/canine rates of formation are indistinguishable from modern humans. Discussion: We invoke a disease and dearth model, with short episodes of distress reflecting onset of disease in young infants, lasting about 3 weeks, followed by a season of undernutrition, possibly intensified by secondary plant compounds, spanning about 12 weeks, inferably coincident with austral winter.
      pubtype: Academic Journal
      doctype: Article
      src: R
    language: English
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