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An investigation on the evolutionary significance of molar and masticatory structure in early hominids and fossil hominoids

Research Project

Project/Area Number 16405016
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section海外学術
Research Field Anthropology
Research InstitutionThe University of Tokyo

Principal Investigator

SUWA Gen  The University of Tokyo, The University Museum, Associate Professor, 総合研究博物館, 助教授 (50206596)

Co-Investigator(Kenkyū-buntansha) KONO Reiko T.  National Science Museum, Department of Anthropology, Researcher, 人類研究部, 研究官 (30356266)
KAIFU Yousuke  National Science Museum, Department of Anthropology, Researcher, 人類研究部, 研究官 (20280521)
KONDO Osamu  The University of Tokyo, Graduate School of Biological Sciences, Associate Professor, 理学系研究科, 助教授 (40244347)
Project Period (FY) 2004 – 2005
Project Status Completed (Fiscal Year 2005)
Budget Amount *help
¥13,300,000 (Direct Cost: ¥13,300,000)
Fiscal Year 2005: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2004: ¥9,100,000 (Direct Cost: ¥9,100,000)
KeywordsEnamel Thickness / Early Hominid / Hominoid / Fossil Taxa / Masticatory Structure / Molar / Microfocus X-ray CT scanning / Functional Morphology
Research Abstract

In the present study, we investigated a broad range of fossil hominid and hominoid specimens in order to contribute to the clarification of the phylogenetic relationships and morphological adaptations of the earliest hominid genera and species of the circum 6 to 4 million year time period. We conducted high resolution micro-CT analysis on selected specimens of Australopithecus and early Homo, systematically assessed enamel thickness on natural fracture surfaces of East African early Homo and Australopithecus species, and acquired micro-CT or natural fracture based data on selected Eurasian and African hominoid taxa. In particular, we successfully obtained 3-dimensionally based high resolution estimations of whole crown enamel volume and distributions with both 'robust' and 'non-robust' Australopithecus molars, from extensive segmentation routines of micro-CT data. Our analyses of these and previously acquired thickness data of the earliest pre-4 myr hominids included the assessment of 1) the extent to which section position and orientation affect linear thickness measures, 2) the relationship between 3-dimensional volumetric and 2-dimensional section-based linear thickness measures, and 3) a comparative analysis of the fossil hominid and hominoid molars based on these methodological considerations. Results suggested that 1)the earliest pre-4.2 myr hominids have enamel thinner than the Australopithecus species, 2) Au. anamensis have thicker enamel than in previous hominids, but an overall intermediate molar structure compared with Au.afarensis, 3)there appears to be an overall size-related increase in enamel thickness within Australopithecus species, and 4)previous characterization of Miocene hominoid enamel thickness may be biased by inadequate methodologies. We have also documented considerable individual variation within species, calling for the need to gather larger samples by combining both CT and section data within an integrated methodological framework.

Report

(3 results)
  • 2005 Annual Research Report   Final Research Report Summary
  • 2004 Annual Research Report
  • Research Products

    (18 results)

All 2006 2005 2004 Other

All Journal Article (18 results)

  • [Journal Article] Assa Issie,Aramis,and the origin of Australopithecus.2006

    • Author(s)
      White et al.
    • Journal Title

      Nature 440

      Pages: 883-889

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Assa Issie, Aramis and the origin of Australopithecus.2006

    • Author(s)
      White TD et al.
    • Journal Title

      Nature 440

      Pages: 883-889

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] A micro-CT based study of linear enamel thickness in the mesial cusp section of human molars : reevaluation of methodology and assessment of within-tooth,serial,and individual variation.2005

    • Author(s)
      Suwa G, Kono RT
    • Journal Title

      Anthropological Science 113

      Pages: 273-289

    • NAID

      10017171410

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Molar enamel thickness of Australopithecus africanus and A.robustus.2005

    • Author(s)
      Kono RT, Suwa G
    • Journal Title

      Anthropological Science 113

      Pages: 323-323

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Time transgressive morphological changes in Australopithecus boisei-a preliminary report.2005

    • Author(s)
      Suwa G, Kono RT, Asfaw B
    • Journal Title

      Anthropological Science 113

      Pages: 323-323

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Effects of molar crown orientation to measures of lateral enamel thickness in the mesial cusp section.2005

    • Author(s)
      Kono RT, Suwa G
    • Journal Title

      Bulletin of the National Science Museum,Series D 31

      Pages: 1-122

    • NAID

      110006141344

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] A micro-CT based study of linear enamel thickness in the mesial cusp section of human molars : reevaluation of methodology and assessment of within-tooth, serial, and individual variation.2005

    • Author(s)
      Suwa G, Kono RT
    • Journal Title

      Anthropological Science 113

      Pages: 273-289

    • NAID

      10017171410

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Molar enamel thickness of Australopithecus africanus and A.robustus2005

    • Author(s)
      Kono RT, Suwa G
    • Journal Title

      Anthropological Science 113

      Pages: 323-323

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Time transgressive morphological changes in Australopithecus boisei - a preliminary report.2005

    • Author(s)
      Suwa G, Kono RT, Asfaw B
    • Journal Title

      Anthropological Science 113

      Pages: 323-323

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Effects of molar crown orientation to measures of lateral enamel thickness in the mesial cusp section.2005

    • Author(s)
      Kono RT, Suwa G
    • Journal Title

      Bulletin of the National Science Museum Tokyo, Series D, 31

      Pages: 11-22

    • NAID

      110006141344

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] A micro-CT based study of linear enamel thickness in the mesial cusp section of human molars: reevalution of mathodology and assessment of within-tooth, serial, and individual variation2005

    • Author(s)
      Suwa G, Kono RT
    • Journal Title

      Anthropological Science 113

      Pages: 273-289

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Effects of molar crown orientation to measures of lateral enamel thickness in the mesial cusp section.2005

    • Author(s)
      Kono R.T., Suwa G.
    • Journal Title

      Bulletin of the National Science Museum, Tokyo, Series D 31

      Pages: 11-22

    • NAID

      110006141344

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Molar enamel thickness of Australopithecus africanus and A. robustus2005

    • Author(s)
      Kono R.T., Suwa G.
    • Journal Title

      Anthropological Science 113

      Pages: 323-323

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Liner enamel thickness evaluation in the MCS of modern human molars.2004

    • Author(s)
      Kono RT, Suwa G
    • Journal Title

      Anthropological Science 112

      Pages: 300-300

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Linear enamel thickness evaluation in the MCS of modern human molars.2004

    • Author(s)
      Kono RT, Suwa G
    • Journal Title

      Anthropological Science 112

      Pages: 300-300

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Linear enamel thickness evaluation in the MCS of modern human molars.2004

    • Author(s)
      Kono RT, Suwa G
    • Journal Title

      Anthropological Science 112-3

      Pages: 300-300

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Assa Issie, Arams, and the origin of Australopithecus

    • Author(s)
      White T 他
    • Journal Title

      Nature (印刷中)

    • Related Report
      2005 Annual Research Report
  • [Journal Article] A micro-CT based study of linear enamel thickness in the mesial cusp section of human molars : reevaluation of methodology and assessment of within-tooth, serial, and individual variation

    • Author(s)
      Suwa G, Kono RT
    • Journal Title

      Anthropological Science (印刷中)

    • NAID

      10017171410

    • Related Report
      2004 Annual Research Report

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Published: 2004-04-01   Modified: 2016-04-21  

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