Functional morphology, stable isotopes, and human evolution: a model of consilience

Area of Science:

• Paleoanthropology
• Biomechanics
• Paleoecology

Background:

• Hominin foraging is limited by food energy and processing mechanics.
• Thick molar enamel and megadontia, prominent in Paranthropus, are linked to chewing hard foods.
• Plant underground storage organs (USOs) are hypothesized as a key resource for Paranthropus.

Purpose of the Study:

• To model foraging constraints in human ancestors based on energy needs and enamel wear.
• To evaluate the fitness advantages of megadontia.
• To determine conditions under which USOs would be fallback versus preferred foods.

Main Methods:

• Development of a process-based model simulating foraging.
• Analysis of energetic demands and enamel wear.
• Exploration of resource selection strategies.

Main Results:

• The model provides insights into the functional interpretations of megadontia.
• It reconciles discrepancies between functional morphology and microwear evidence.
• Predictions are made regarding the role of USOs in the diet of Paranthropus boisei.

Conclusions:

• Megadontia likely conferred fitness benefits by enabling the processing of mechanically challenging foods.
• The model helps explain dietary strategies of extinct hominins, particularly Paranthropus.
• Stiff foods like USOs may have been crucial fallback resources, influencing hominin evolution.