The age-related emergence of cranial morphological variation.

Evaluation of ancestry from skeletal remains is problematic for subadults because of a lack of systematic research on the topic. This paper addresses the need for systematic research into geographical variation through childhood and puberty through the examination of the emergence of cranial morphological traits through an analysis of 756 subadults from 4 months in utero to <20 years of age. The first appearance of a trait, changes in the morphology of a trait through time, age stability as related to the age of maturation of the structure, and the developmental mechanisms and processes that cause traits to appear together are addressed. Most traits are influenced by patterns of growth and development and become age stable in conjunction with the larger growth complexes of which they are a part. Geographic cranial variation is present from an early age. Population specific differences in the expression of most traits are apparent from their first appearance.