The differences in the superfamily Cercopithecoids and Hominoids can be related to the fact that the common ancestor of apes and humans was adapted for suspending the body by the forelimbs and brachiating. The Cercopithecoids (like most mammals) are adapted for quadrapedalism (walking on all fours) while hominoids locomote bipedally (upright on two legs).
Cercopithecoidea (Old World Monkeys): colobus monkeys, proboscis monkeys, golden monkeys, langurs, leaf monkeys, baboons, macaques, geladas, guenons, and mandrills.
Hominoidea (Apes and Humans): gibbons, orangutans, gorillas, chimpanzees, bonobos, and humans. Apes are generally larger in body size compared to other primates.
There are some physical traits that are unique to Hominoids (Apes and Humans)
Primates can exhibit one of two morphological structures of their molars: bilophodont or Y5. Bilophodont molars have four cusps, or points, arranged in two parallel pairs, and are present in superfamily Cercopithecoidea. Hominoids, on the other hand, have 5 cusps that are form a “Y” space between the cusps. Humans/apes are the only group of primates to exhibit this trait.
Rhesus Macaque mandible
Apes don’t have em. (All other primates do!)
Station 4 Exercise: Look closely at the skulls and skeletons, then complete the chart below.
Which do you think is the ancestral condition in Catarrhini (the group that includes Old World Monkeys, Apes and Humans): having a tail, or being tail-less? Why?