Gorilla calcaneal morphological variation and ecological divergence

Objectives The primate foot has been extensively investigated because of its role in weight‐bearing; however, the calcaneus has been relatively understudied. Here we examine entire gorilla calcaneal external shape to understand its relationship with locomotor behavior. Materials and methods Calcanei of Gorilla gorilla gorilla (n = 43), Gorilla beringei graueri (n = 20), and Gorilla beringei beringei (n = 15) were surface or micro‐CT scanned. External shape was analyzed through a three‐dimensional geometric morphometric sliding semilandmark analysis. Semilandmarks were slid relative to an updated Procrustes average in order to minimize the bending energy of the thin plate spline interpolation function. Shape variation was summarized using principal components analysis of shape coordinates. Procrustes distances between taxa averages were calculated and resampling statistics run to test pairwise differences. Linear measures were collected and regressed against estimated body mass. Results All three taxa exhibit statistically different morphologies (p