What lies beneath? An evaluation of lower molar trigonid crest patterns based on both dentine and enamel expression

Bailey, Shara E. and Skinner, Matthew M. and Hublin, Jean-Jacques (2011) What lies beneath? An evaluation of lower molar trigonid crest patterns based on both dentine and enamel expression. American Journal of Physical Anthropology, 145 (4). pp. 505-518. ISSN 1096-8644. (doi:https://doi.org/10.1002/ajpa.21468) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1002/ajpa.21468

Abstract

The nearly ubiquitous presence of a continuous crest connecting the protoconid and metaconid of the lower molars (often referred to as the middle trigonid crest), is one of several dental traits that distinguish Homo neanderthalensis from Homo sapiens. This study examined variation in trigonid crest patterns on the enamel and dentine surfaces to (1) evaluate the concordance between the morphology of trigonid crests at the inner dentine and the outer enamel surfaces; (2) examine their developmental origin(s); and (3) examine trait polarity through comparison with Australopithecus africanus and Pan. The sample included 73 H. neanderthalensis, 67 contemporary H. sapiens, 5 A. africanus, and 24 Pan lower molars. Results indicate general agreement in the morphology observed on the dentine and enamel surfaces. All but one H. neanderthalensis molar shows some trigonid crest development, whereas trigonid crests occur in low frequency in contemporary humans. Pan and A. africanus both also show high frequencies of a continuous trigonid crest. However, the origin of the trigonid crest differs among groups. H. neanderthalensis uniquely possesses a ‘middle’ trigonid crest that originates from the mesial accessory ridge of one or both cusps. Based on our results we suggest that presence of a continuous middle trigonid crest at the dentine surface is primitive and the lack of any trigonid crest is derived. Genetic drift may explain the high frequency of trigonid crests in H.neanderthalensis. However, H. neanderthalensis still appears to be derived relative to Pan and A. africanus in its high frequency of the mesial-mesial trigonid crestconfiguration.

Item Type: Article
Uncontrolled keywords: H. neanderthalensis;H. sapiens;Neandertals;modern humans;Pan;Australopithecus;middle trigonid crest;microCT;discrete dental traits
Subjects: Q Science
Divisions: Faculties > Social Sciences > School of Anthropology and Conservation > Biological Anthropology
Depositing User: Matthew Skinner
Date Deposited: 15 May 2015 12:34 UTC
Last Modified: 18 May 2015 09:17 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/48474 (The current URI for this page, for reference purposes)
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