catarrhines

Catarrhines are a parvorder of primates that includes all Old World monkeys and the apes, including humans. They are distinguished from platyrrhines (New World monkeys) by several features, notably downward-facing nostrils that are relatively close together and a dental formula of 2.1.2.3 on each side of the jaw. Most catarrhines lack a prehensile tail; apes are tailless, while many Old World monkeys have non-prehensile tails.

The catarrhine primates are divided into two superfamilies: Cercopithecoidea (Old World monkeys) and Hominoidea (apes, including humans). Members of Cercopithecoidea include baboons, macaques, langurs, and colobines; Hominoidea comprises the lesser apes (gibbons) and the great apes (orangutans, gorillas, chimpanzees) plus Homo sapiens.

Origin and distribution: Catarrhines originated in Africa and Asia. They diverged from the platyrrhines roughly 40–45 million years ago. Within Catarrhini, the lineages leading to Cercopithecoidea and Hominoidea split about 25–30 million years ago. Today, catarrhines occur across Africa and Asia, with humans achieving a global distribution.

Biology and behavior: Catarrhines generally have larger brains relative to body size than many platyrrhines and exhibit diverse social structures. They display advanced vision and grasping abilities, with skeletal and dental traits used in classification. Ecology ranges from tropical forests to savannas and urban environments.