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Dietary effects on development of the human mandibular corpus
Megan A Holmes1, Christopher B Ruff
1Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. megholmes@jhmi.edu
American Journal of Physical Anthropology
|June 25, 2011
Summary
Mandibular shape in humans develops with age, influenced by diet. A study comparing Alaskan Tigara and South Dakota Arikara populations found that demanding diets lead to stronger, wider mandibles in adults.
Area of Science:
- Paleoanthropology
- Bioarchaeology
- Human Evolution
Background:
- Mandibular corpus plasticity is key to understanding fossil and archaeological human remains.
- Diet significantly impacts craniofacial development and biomechanics.
Purpose of the Study:
- To investigate ontogenetic changes in mandibular corpus breadth, rigidity, and strength.
- To compare these changes between populations with contrasting dietary regimes: Tigara (Alaska) and Arikara (South Dakota).
Main Methods:
- Analysis of 52 juvenile and 11 adult Tigara, and 32 juvenile and 10 adult Arikara mandibles.
- Measurement of mandibular bone breadths using calipers and biplanar radiographs.
- Application of an asymmetrical hollow beam model to calculate bending rigidities and strengths.
Main Results:
- Adult Tigara exhibit greater transverse corpus width, bending rigidity, and strength compared to adult Arikara.
- These morphological differences emerge gradually during growth, becoming more pronounced in adolescence.
- Functional mechanical loading during growth influences adult mandibular morphology.
Conclusions:
- Dietary differences play a significant role in shaping mandibular morphology during ontogeny.
- The study highlights the adaptive plasticity of the human mandible in response to mechanical stress.
- Understanding developmental plasticity is crucial for interpreting hominin fossil records.
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