Catarrhini is one of the two major infraorders of primates, studied in anthropology, primatology, and evolutionary biology. It includes all Old World monkeys, apes, and humans, distinguished by key anatomical and evolutionary traits.
🌍 Definition
- Catarrhini: Infraorder of primates native to Africa and Asia.
- Name Origin: From Greek kata- (“down”) + rhinos (“nose”), referring to their downward-facing nostrils.
- Contrast: Opposite of Platyrrhini (New World monkeys), which have broad, outward-facing nostrils.
🔑 Characteristics
- Nasal Structure: Narrow, downward-facing nostrils (catarrhine nose).
- Dental Formula: 2.1.2.3 (two incisors, one canine, two premolars, three molars per quadrant).
- Tail: Old World monkeys often have non-prehensile tails; apes and humans lack tails entirely.
- Vision: Trichromatic color vision common.
- Geography: Africa and Asia (vs. Platyrrhines in Central and South America).
📚 Anthropological & Evolutionary Contexts
- Old World Monkeys (Cercopithecoidea): Baboons, macaques, colobus monkeys.
- Apes (Hominoidea): Gibbons, orangutans, gorillas, chimpanzees, humans.
- Evolutionary Divergence:
- Catarrhines split from Platyrrhines ~35–40 million years ago.
- Fossil evidence from the Fayum Depression (Egypt) shows early catarrhines like Aegyptopithecus.
- Human Connection: Humans are catarrhines, sharing traits with other Old World primates.
In short: Catarrhini is the infraorder of Old World primates—including monkeys, apes, and humans—defined by downward-facing nostrils, a 2.1.2.3 dental formula, and evolutionary divergence from New World monkeys.
