Global elongation and high shape flexibility as an evolutionary hypothesis of accommodating mammalian brains into skulls

• DOI: 10.1111/evo.14163
• Publication Date: 2021-01-23T06:22:55Z
• Authors: Vera Weisbecker; Timothy Rowe; Stephen Wroe; Thomas E. Macrini; Kathleen L. S. Ga...; Kenny J. Travouillon; Karen Black; Michael Archer; Suzanne J. Hand; Jeri C. Berlin; Robin M.D. Beck; Sandrine Ladevèze; Alana C. Sharp; Karine Mardon; Emma Sherratt
• Keywords: Endocast; Encephalization; Morphometrics; Allometry; Variation (astronomy)

Little is known about how the large brains of mammals are accommodated into dazzling diversity their skulls. It has been suggested that brain shape influenced by relative size, it evolves or develops according to extrinsic intrinsic mechanical constraints, and its can provide insights proportions function. Here, we characterize variation among 84 marsupial cranial endocasts 57 species including fossils, using three-dimensional geometric morphometrics virtual dissections. Statistical analysis revealed four main patterns: over half endocast ranges from elongate straight globular inclined; little allometric with respect centroid none for volume; no association between locomotion shape; limited previously published histological cortex volumes. Fossil tend have smaller cerebral hemispheres. We find divergent shapes in closely related within species, diverse morphologies superimposed variation. An evolutionarily individually malleable a fundamental tendency arrange spectrum elongate-to-globular shapes-possibly mostly independent function-may explain accommodation enormous mammalian skull form.