AP BIOLOGY

Detailed explanation-1: -In New World monkeys (the Platyrrhini, meaning “flat nosed”), the nose is broad, and the nostrils are set wide apart, well separated by a broad septum, and point sideways.

Detailed explanation-2: -Platyrrhines are primates belonging to the parvorder Platyrrhini. They are characterized by having a broad, flat nose and with sideways-facing nostrils. They have prehensile tails, which are long, grasping tails. They have twelve premolars (as opposed to the eight premolars in catarrhine primates).

Detailed explanation-3: -Catarrhines and platyrrhines are distinguished by the shape of their nostrils. Catarrhines have narrow downward facing nostrils, while platyrrhines have broad, flat, sideways facing nostrils.

Detailed explanation-4: -The two derived traits are the grooming claw (Figure 5.13), which is on the second digit of each foot, and the tooth comb (or dental comb), located on the lower, front teeth (Figure 5.15). In most strepsirrhines, there are six teeth in the toothcomb-the four incisors and the two canines.