Growth of the fetal pigtailed macaque (Macaca nemestrina) I. Cephalofacial dimensions.

The prenatal growth of the macaque cephalofacial region is described using cephalofacial measurements taken on 89 fetal Macaca nemestrina whose known gestational ages range from 60 to 184 days. During the prenatal period, the macaque neurocranium flattens and elongates in an anteroposterior direction; the height of the upper face increases at a faster rate than facial breadth, and the ear dimensions grow at a faster rate than any other cephalofacial dimension. Formulae based on the independent variables of ear height and bizygomatic diameter are recommended for estimating fetal age in this species.