The Influence of Geographic Isolation on the Skull of the Green Monkey (Cercopithecus aethiops sabaeus). I. A Comparison between the Teeth of the St Kitts and the African Green Monkey

A quantitative analysis has been made of the dental dimensions and indices of (a) a collection of skulls of the green monkey (Cercopithecus aethiops sabaeus) brought together from the island of St Kitts in the West Indies, and (b) a corresponding group of green monkey skulls collected in West Africa. The green monkey was introduced into St Kitts some 300 years ago; the African green monkey is the modern representative of its parent stock. Comparison shows that (a) the teeth of the green monkey in the West Indies are bigger than those of its present-day African cousin; (b) that there has been a decrease in the variance of the linear dimensions of the cheek teeth; and (c) that there has been an increase in the occurrence of such dental abnormalities as malposition, numerical variations, and variations in the number of roots of the third molar. These changes can be explained as an effect of selection acting on the original genetic constitution of the stock of green monkeys which became established in the Caribbean.