Phylogenetic and environmental effects on limb bone structure in gorillas

Area of Science:

• Primate anatomy and biomechanics
• Evolutionary biology
• Paleoanthropology

Background:

• Understanding how environmental factors influence skeletal development is crucial for evolutionary studies.
• Gorilla subspecies exhibit diverse ecological niches and locomotor behaviors.

Purpose of the Study:

• To investigate the influence of phylogeny versus locomotor behavior on long bone structural proportions in gorillas.
• To compare adult and ontogenetic samples to understand developmental plasticity.

Main Methods:

• Analysis of 281 wild-collected gorillas across four subspecies.
• Measurement of long bone lengths, articular breadths, and diaphyseal cross-sectional geometric properties using CT scans.
• Assessment of age-related changes in limb proportions from infancy to adulthood.

Main Results:

• Adult gorillas' diaphyseal strength proportions correlate with behavioral differences (arboreal vs. terrestrial), not phylogeny.
• Forelimb strength is greater in arboreal gorillas, while terrestrial gorillas have relatively stronger hind limbs.
• Limb strength proportions diverge after two years of age, coinciding with behavioral changes, while length and articular proportions remain consistent.

Conclusions:

• Long bone diaphyseal strength in gorillas is developmentally plastic and influenced by behavior.
• Skeletal length and articular proportions are more genetically determined.
• These findings aid in interpreting morphological variations in fossil hominins.