Taxonomic differences in deciduous upper second molar crown outlines of Homo sapiens, Homo neanderthalensis and Homo erectus

Shara Bailey, Stefano Benazzi, Caroline Souday, Claudia Astorino, Kathleen Paul, Jean Jacques Hublin

    Research output: Contribution to journalArticle

    Abstract

    A significant number of Middle to Late Pleistocene sites contain primarily (and sometimes only) deciduous teeth (e.g., Grotta del Cavallo, Mezmaiskaya, Blombos). Not surprisingly, there has been a recent renewed interest in deciduous dental variation, especially in the context of distinguishing Homo neanderthalensis and Homo sapiens. Most studies of the deciduous dentition of fossil hominins have focused on standard metrical variation but morphological (non-metric and morphometric) variation also promises to shed light on long standing taxonomic questions. This study examines the taxonomic significance of the crown outline of the deciduous upper second molar through principal components analysis and linear discriminant analysis. We examine whether or not the crown shape of the upper deciduous second molar separates H.neanderthalensis from H.sapiens and explore whether it can be used to correctly assign individuals to taxa. It builds on previous studies by focusing on crown rather than cervical outline and by including a large sample of geographically diverse recent human populations. Our samples include 17 H.neanderthalensis, five early H.sapiens, and 12 Upper Paleolithic H.sapiens. In addition, we include two Homo erectus specimens in order to evaluate the polarity of crown shape differences observed between H.neanderthalensis and H.sapiens. Our results show that crown outline shape discriminates H.sapiens and H.neanderthalensis quite well, but does not do well at distinguishing H.erectus from H.sapiens. We conclude that the crown outline shape observed in H.sapiens is a primitive retention and that the skewed shape observed in H.neanderthalensis is a derived condition. Finally, we explore the phylogenetic implications of the results for the H.erectus molars.

    Original languageEnglish (US)
    Pages (from-to)1-9
    Number of pages9
    JournalJournal of Human Evolution
    Volume72
    DOIs
    StatePublished - 2014

    Fingerprint

    Homo
    discriminant analysis
    teeth
    dentition
    Paleolithic
    human population
    tooth
    principal component analysis
    fossils
    Homo sapiens
    Homo Sapiens
    Homo Erectus
    Pleistocene
    fossil
    phylogenetics
    sampling
    phylogeny

    Keywords

    • Dental variation
    • Geometric morphometrics
    • Molar crown shape
    • Phylogeny
    • Pleistocene
    • Sangiran
    • Tighenif

    ASJC Scopus subject areas

    • Ecology, Evolution, Behavior and Systematics
    • Education
    • Arts and Humanities (miscellaneous)

    Cite this

    Taxonomic differences in deciduous upper second molar crown outlines of Homo sapiens, Homo neanderthalensis and Homo erectus. / Bailey, Shara; Benazzi, Stefano; Souday, Caroline; Astorino, Claudia; Paul, Kathleen; Hublin, Jean Jacques.

    In: Journal of Human Evolution, Vol. 72, 2014, p. 1-9.

    Research output: Contribution to journalArticle

    Bailey, Shara ; Benazzi, Stefano ; Souday, Caroline ; Astorino, Claudia ; Paul, Kathleen ; Hublin, Jean Jacques. / Taxonomic differences in deciduous upper second molar crown outlines of Homo sapiens, Homo neanderthalensis and Homo erectus. In: Journal of Human Evolution. 2014 ; Vol. 72. pp. 1-9.
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    abstract = "A significant number of Middle to Late Pleistocene sites contain primarily (and sometimes only) deciduous teeth (e.g., Grotta del Cavallo, Mezmaiskaya, Blombos). Not surprisingly, there has been a recent renewed interest in deciduous dental variation, especially in the context of distinguishing Homo neanderthalensis and Homo sapiens. Most studies of the deciduous dentition of fossil hominins have focused on standard metrical variation but morphological (non-metric and morphometric) variation also promises to shed light on long standing taxonomic questions. This study examines the taxonomic significance of the crown outline of the deciduous upper second molar through principal components analysis and linear discriminant analysis. We examine whether or not the crown shape of the upper deciduous second molar separates H.neanderthalensis from H.sapiens and explore whether it can be used to correctly assign individuals to taxa. It builds on previous studies by focusing on crown rather than cervical outline and by including a large sample of geographically diverse recent human populations. Our samples include 17 H.neanderthalensis, five early H.sapiens, and 12 Upper Paleolithic H.sapiens. In addition, we include two Homo erectus specimens in order to evaluate the polarity of crown shape differences observed between H.neanderthalensis and H.sapiens. Our results show that crown outline shape discriminates H.sapiens and H.neanderthalensis quite well, but does not do well at distinguishing H.erectus from H.sapiens. We conclude that the crown outline shape observed in H.sapiens is a primitive retention and that the skewed shape observed in H.neanderthalensis is a derived condition. Finally, we explore the phylogenetic implications of the results for the H.erectus molars.",
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    AU - Bailey, Shara

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    AU - Astorino, Claudia

    AU - Paul, Kathleen

    AU - Hublin, Jean Jacques

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