Cranial shape and size variation in human evolution: structural and functional perspectives.

A GLIMPSE INTO MODERN PALEOANTHROPOLOGY: In the last decades, paleoanthropology has been deeply modified, changing from a descriptive and historical science to a more quantitative and analytical discipline. The covariation of multiple traits is investigated to study the evolutionary changes of the underlying anatomical models, mostly through the introduction of digital biomedical imaging procedures and of computed geometrical analyses supported by multivariate statistics. FUNCTIONAL CRANIOLOGY: The evolution of the human cranium is consequently considered in terms of functional and structural relationships between its components, largely influenced by the allometric variations associated with the increase in the relative cranial capacity. In the human genus, the changes in the face, base, and neurocranium are characterised by a mosaic variation, in which adaptations, secondary consequences, and stochastic factors concur to generate a set of anatomical possibilities and constraints. SYSTEMIC PERSPECTIVES TO THE EVOLUTION OF THE HUMAN CRANIAL MORPHOLOGY: Concepts like morphological modularity, anatomical integration, and heterochrony represent key issues in the development of the current human evolutionary studies.