Diagnostic differences in mandibular P4 shape between neandertals and anatomically modern humans

Shara Bailey, John M. Lynch

    Research output: Contribution to journalArticle

    Abstract

    This study uses elliptical Fourier analysis to quantify shape differences observed in the P4 crown of Neandertals and anatomically modern humans. Previously, P4 shape was assessed qualitatively, and results suggested marked differences between Neandertals and anatomically modern humans (Bailey [2002] New Anat. 269:148-156). The goal of this study was to investigate the P4 shape in more detail, quantifying it in order to determine its utility for taxonomic classification and phylogenetic analysis. A comparison of mean shapes confirms that the mesiolingual portion of the P4 is truncated in Neandertals, and that this produces a distinctively asymmetrical P4. A randomization test confirms that the shape difference between Neandertals and anatomically modern humans is significant. Principal component and discriminant function analyses indicate that the relative size of the lingual portion of the tooth also affects tooth shape, with the lingual portion of the Neandertal P4 being narrower than that of anatomically modern humans. Classification of P4 crown shapes using discriminant functions analysis is far from perfect. While 86.4% of the teeth were correctly classified, classification was much better for anatomically modern humans (98.1%) than it was for Neandertals (65%). Fortunately, crown shape is but one of several diagnostic characters of the P4 crown. P4 crown asymmetry can be added to the growing list of dental morphological characters distinguishing Neandertals from anatomically modern humans. Moreover, based on a comparison of mean tooth shapes in fossil and recent humans, symmetry, rather than asymmetry, appears to be the primitive state, and the high frequency of P4 asymmetry is likely derived in Neandertals.

    Original languageEnglish (US)
    Pages (from-to)268-277
    Number of pages10
    JournalAmerican Journal of Physical Anthropology
    Volume126
    Issue number3
    DOIs
    StatePublished - Mar 2005

    Fingerprint

    Neanderthals
    asymmetry
    diagnostic
    Crowns
    Tooth
    Discriminant Analysis
    Tongue
    Portion Size
    Fossils
    Fourier Analysis
    Random Allocation

    Keywords

    • Elliptic Fourier analysis
    • Morphometrics
    • Postcanine dental morphology

    ASJC Scopus subject areas

    • Anatomy
    • Anthropology

    Cite this

    Diagnostic differences in mandibular P4 shape between neandertals and anatomically modern humans. / Bailey, Shara; Lynch, John M.

    In: American Journal of Physical Anthropology, Vol. 126, No. 3, 03.2005, p. 268-277.

    Research output: Contribution to journalArticle

    @article{d78987e2ac2f49808ab60e43924d9819,
    title = "Diagnostic differences in mandibular P4 shape between neandertals and anatomically modern humans",
    abstract = "This study uses elliptical Fourier analysis to quantify shape differences observed in the P4 crown of Neandertals and anatomically modern humans. Previously, P4 shape was assessed qualitatively, and results suggested marked differences between Neandertals and anatomically modern humans (Bailey [2002] New Anat. 269:148-156). The goal of this study was to investigate the P4 shape in more detail, quantifying it in order to determine its utility for taxonomic classification and phylogenetic analysis. A comparison of mean shapes confirms that the mesiolingual portion of the P4 is truncated in Neandertals, and that this produces a distinctively asymmetrical P4. A randomization test confirms that the shape difference between Neandertals and anatomically modern humans is significant. Principal component and discriminant function analyses indicate that the relative size of the lingual portion of the tooth also affects tooth shape, with the lingual portion of the Neandertal P4 being narrower than that of anatomically modern humans. Classification of P4 crown shapes using discriminant functions analysis is far from perfect. While 86.4{\%} of the teeth were correctly classified, classification was much better for anatomically modern humans (98.1{\%}) than it was for Neandertals (65{\%}). Fortunately, crown shape is but one of several diagnostic characters of the P4 crown. P4 crown asymmetry can be added to the growing list of dental morphological characters distinguishing Neandertals from anatomically modern humans. Moreover, based on a comparison of mean tooth shapes in fossil and recent humans, symmetry, rather than asymmetry, appears to be the primitive state, and the high frequency of P4 asymmetry is likely derived in Neandertals.",
    keywords = "Elliptic Fourier analysis, Morphometrics, Postcanine dental morphology",
    author = "Shara Bailey and Lynch, {John M.}",
    year = "2005",
    month = "3",
    doi = "10.1002/ajpa.20037",
    language = "English (US)",
    volume = "126",
    pages = "268--277",
    journal = "American Journal of Physical Anthropology",
    issn = "0002-9483",
    publisher = "Wiley-Liss Inc.",
    number = "3",

    }

    TY - JOUR

    T1 - Diagnostic differences in mandibular P4 shape between neandertals and anatomically modern humans

    AU - Bailey, Shara

    AU - Lynch, John M.

    PY - 2005/3

    Y1 - 2005/3

    N2 - This study uses elliptical Fourier analysis to quantify shape differences observed in the P4 crown of Neandertals and anatomically modern humans. Previously, P4 shape was assessed qualitatively, and results suggested marked differences between Neandertals and anatomically modern humans (Bailey [2002] New Anat. 269:148-156). The goal of this study was to investigate the P4 shape in more detail, quantifying it in order to determine its utility for taxonomic classification and phylogenetic analysis. A comparison of mean shapes confirms that the mesiolingual portion of the P4 is truncated in Neandertals, and that this produces a distinctively asymmetrical P4. A randomization test confirms that the shape difference between Neandertals and anatomically modern humans is significant. Principal component and discriminant function analyses indicate that the relative size of the lingual portion of the tooth also affects tooth shape, with the lingual portion of the Neandertal P4 being narrower than that of anatomically modern humans. Classification of P4 crown shapes using discriminant functions analysis is far from perfect. While 86.4% of the teeth were correctly classified, classification was much better for anatomically modern humans (98.1%) than it was for Neandertals (65%). Fortunately, crown shape is but one of several diagnostic characters of the P4 crown. P4 crown asymmetry can be added to the growing list of dental morphological characters distinguishing Neandertals from anatomically modern humans. Moreover, based on a comparison of mean tooth shapes in fossil and recent humans, symmetry, rather than asymmetry, appears to be the primitive state, and the high frequency of P4 asymmetry is likely derived in Neandertals.

    AB - This study uses elliptical Fourier analysis to quantify shape differences observed in the P4 crown of Neandertals and anatomically modern humans. Previously, P4 shape was assessed qualitatively, and results suggested marked differences between Neandertals and anatomically modern humans (Bailey [2002] New Anat. 269:148-156). The goal of this study was to investigate the P4 shape in more detail, quantifying it in order to determine its utility for taxonomic classification and phylogenetic analysis. A comparison of mean shapes confirms that the mesiolingual portion of the P4 is truncated in Neandertals, and that this produces a distinctively asymmetrical P4. A randomization test confirms that the shape difference between Neandertals and anatomically modern humans is significant. Principal component and discriminant function analyses indicate that the relative size of the lingual portion of the tooth also affects tooth shape, with the lingual portion of the Neandertal P4 being narrower than that of anatomically modern humans. Classification of P4 crown shapes using discriminant functions analysis is far from perfect. While 86.4% of the teeth were correctly classified, classification was much better for anatomically modern humans (98.1%) than it was for Neandertals (65%). Fortunately, crown shape is but one of several diagnostic characters of the P4 crown. P4 crown asymmetry can be added to the growing list of dental morphological characters distinguishing Neandertals from anatomically modern humans. Moreover, based on a comparison of mean tooth shapes in fossil and recent humans, symmetry, rather than asymmetry, appears to be the primitive state, and the high frequency of P4 asymmetry is likely derived in Neandertals.

    KW - Elliptic Fourier analysis

    KW - Morphometrics

    KW - Postcanine dental morphology

    UR - http://www.scopus.com/inward/record.url?scp=13544271764&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=13544271764&partnerID=8YFLogxK

    U2 - 10.1002/ajpa.20037

    DO - 10.1002/ajpa.20037

    M3 - Article

    VL - 126

    SP - 268

    EP - 277

    JO - American Journal of Physical Anthropology

    JF - American Journal of Physical Anthropology

    SN - 0002-9483

    IS - 3

    ER -