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Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology
Published on: August 22, 2022
A geometric morphometric analysis of hominin upper first molar shape.
A Gómez-Robles1, M Martinón-Torres, J M Bermúdez de Castro
1Centro Nacional de Investigación sobre Evolución Humana (CENIEH), Avda. de la Paz, 28, 09006 Burgos, Spain. aida.gomez@cenieh.es
Journal of Human Evolution
|June 30, 2007
Summary
Geometric morphometrics reveals distinct upper first molar shapes in hominins. Neanderthals exhibit unique lingual cusp displacement and hypocone protrusion, differentiating them from modern humans and earlier hominins.
Area of Science:
- Paleoanthropology
- Evolutionary Biology
- Dental Morphology
Background:
- Classic morphometric studies show differences in upper first molar (M(1)) morphology between Homo sapiens and Homo neanderthalensis.
- Previous analyses relied on cusp areas and angles, providing valuable but potentially limited taxonomic insights.
Purpose of the Study:
- To apply geometric morphometric methods to analyze M(1) morphology across the hominin fossil record.
- To clarify phenetic relationships between European middle Pleistocene populations (Homo heidelbergensis), Homo neanderthalensis, and Homo sapiens.
- To assess trait polarity using Australopithecus and early Homo specimens.
Main Methods:
- Geometric morphometrics applied to upper first molar (M(1)) specimens.
- Comparative analysis of M(1) morphology across diverse hominin taxa.
- Focus on occlusal polygon shape and external outline features.
Main Results:
- Homo neanderthalensis displays a unique M(1) morphology: distally displaced lingual cusps and a prominent hypocone.
- This morphology is present to a lesser degree in European middle Pleistocene hominins, peaking in Neanderthals.
- Homo sapiens retains a primitive M(1) morphology with a square occlusal polygon and round external outline.
Conclusions:
- Geometric morphometrics provides a more conclusive approach to taxonomic assignment using M(1) morphology.
- Distinct M(1) features support the unique evolutionary trajectory of Homo neanderthalensis.
- The study refines our understanding of hominin evolutionary relationships and dental trait diversification.
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