Changes in human mandibular shape during the Terminal Pleistocene-Holocene Levant

Area of Science:

• Paleoanthropology
• Human Evolution
• Bioarchaeology

Background:

• Human dietary shifts, including food production and secondary product exploitation, profoundly impacted human biology.
• Technological advancements in cookware also influenced masticatory stresses and subsequent craniofacial development.

Purpose of the Study:

• To investigate temporal changes in human mandibular form and shape in the Levant from the terminal Pleistocene to the Holocene.
• To analyze the impact of the agricultural revolution on mandibular morphology.

Main Methods:

• Geometric morphometrics (Procrustes-based) applied to 3D surface meshes of hemimandibles.
• Analysis of four distinct populations: Natufian hunter-gatherers, early Neolithic farmers, Chalcolithic farmers, and Roman-Byzantine and modern populations.
• Univariate and multivariate statistical analyses to assess size and shape variations.

Main Results:

• Significant temporal shifts in mandibular shape were observed throughout the Holocene Levant.
• Mandibular size showed a tendency for reduction from pre-agricultural (Natufian) to early farming populations.
• Substantial shape modifications occurred across most mandibular regions, particularly after the advent of agriculture.

Conclusions:

• The agricultural revolution in the Levant led to considerable changes in mandibular shape.
• These morphological alterations support the "masticatory-functional hypothesis," linking mechanical forces to skeletal adaptation.
• Dietary and lifestyle changes associated with agriculture are key drivers of observed human evolutionary changes.