Old World Monkey Morphology

From Primatome

Old World Monkeys, Cercopithecoidea, are the more taxonomically diverse and numerically successful of living catarrhines. Although Old World Monkeys have traditionally been viewed as primitive catarrhines, it has become increasingly evident in recent years that this is a very specialized radiation of Old World primates, one that is not only very different from living apes but also quite derived. We now know that both Old World Monkeys and apes are quite specialized in different ways with respect to the earliest catarrhines.

Cercopithecoid monkeys have several anatomical features that distinguish them from apes and humans. Most characteristic are the specialized molar teeth in which the anterior two cusps and the posterior two cusps are aligned to form two ridges, or lophs. Teeth with this structure are described as bilophodont. Most Old World Monkeys have daggerlike canines in the males and smaller ones in the females. In both males and females, the canines are sharpened by a narrow anterior lower premolar. In cranial anatomy, Old World Monkeys have relatively narrow nasal openings and narrow tooth rows compared with apes.

The limbs of Old World Monkeys are characterized by a very narrow elbow joint with a reduced medial epicondyle and a relatively long olecranon process on the ulna. Sitting pads on the expanded ischial tuberosities are a distinctive feature of the group, and many have a long tail.

-from Primate Adaptation and Evolution by John G. Fleagle (Author)