Monkeys: Anatomical features
The monkeys that reached South America and became isolated there when the isthmus of Panama sank beneath the sea, have developed very much along their own lines. That they all are derived from one common stock is deduced from the number of anatomical features they share e.g. all have fat noses with widely spaced nostrils opening to the side whereas monkeys elsewhere have thin noses with forward or downward pointing nostrils.
Picture Identification was used as aid to identify individuals in research
