Growth pattern from birth to adulthood in African pygmies of known age.

The African pygmy phenotype stems from genetic foundations and is considered to be the product of a disturbance in the growth hormone-insulin-like growth factor (GH-IGF) axis. However, when and how the pygmy phenotype is acquired during growth remains unknown. Here we describe growth patterns in Baka pygmies based on two longitudinal studies of individuals of known age, from the time of birth to the age of 25 years.

East-West cranial differentiation in pre-Columbian populations from Central and North America.

In a recent study we found that crania from South Amerindian populations on each side of the Andes differ significantly in terms of craniofacial shape. Western populations formed one morphological group, distributed continuously over 14,000km from the Fuegian archipelago (southern Chile) to the Zulia region (northwestern Venezuela). Easterners formed another group, distributed from the Atlantic Coast up to the eastern foothills of the Andes.

Developmental connections between cranial components and the emergence of the first permanent molar in humans.

The age of emergence of the first molar (M1) is a developmental event correlated with many variables of primate life history, such as adult brain size. The evolution of human life history is characterized by the inclusion of childhood, which takes place between weaning and M1 emergence. Children still depend on adults for nutrition due to their small digestive system and their immature brains.

Variation in enamel development of South African fossil hominids.

Dental tissues provide important insights into aspects of hominid palaeobiology that are otherwise difficult to obtain from studies of the bony skeleton. Tooth enamel is formed by ameloblasts, which demonstrate daily secretory rhythms developing tissue-specific structures known as cross striations, and longer period markings called striae of Retzius. These enamel features were studied in the molars of two well known South African hominid species, Australopithecus africanus and Paranthropus robustus.

East-West cranial differentiation in pre-Columbian human populations of South America.

South Amerindians are frequently thought of as a rather biologically homogeneous megapopulation. However, when native South Americans are assessed by information coming from DNA variability analysis, they resolve into two, major distinct entities of Eastern and Western zones. The purpose of this study is to investigate if the same dual pattern emerges from craniometric data.