key term - Catarrhini

Definition

Catarrhini is the infraorder of primates that includes the Old World monkeys and apes. It is one of the two major groups of primates, the other being Platyrrhini (New World monkeys).

5 Must Know Facts For Your Next Test

1. Catarrhini primates are distinguished by their narrow nasal openings, which face downward, unlike the wider, sideways-facing nostrils of Platyrrhini (New World monkeys).
2. Catarrhini includes Old World monkeys, such as baboons, macaques, and colobus monkeys, as well as the apes, including humans, chimpanzees, gorillas, orangutans, and gibbons.
3. Catarrhini primates are generally larger in size and have a more complex social structure compared to Platyrrhini primates.
4. Catarrhini primates are found primarily in Africa and Asia, while Platyrrhini primates are found in the Americas.
5. The evolutionary divergence between Catarrhini and Platyrrhini is estimated to have occurred around 25-30 million years ago.

Review Questions

• Describe the key anatomical features that distinguish Catarrhini primates from Platyrrhini primates.
  • The primary anatomical feature that distinguishes Catarrhini primates from Platyrrhini primates is the shape and orientation of their nasal openings. Catarrhini primates have narrow, downward-facing nasal openings, while Platyrrhini primates have wider, sideways-facing nostrils. This difference in nasal structure is a result of their evolutionary divergence and adaptation to different environments. Additionally, Catarrhini primates are generally larger in size and have a more complex social structure compared to their New World counterparts.
• Explain the geographic distribution and evolutionary history of the Catarrhini infraorder.
  • Catarrhini primates are found primarily in Africa and Asia, while Platyrrhini primates are found in the Americas. This geographic separation is a result of the evolutionary divergence between the two infraorders, which is estimated to have occurred around 25-30 million years ago. The Catarrhini lineage, including Old World monkeys and apes, evolved and diversified in the Old World, adapting to the unique environmental and ecological conditions of Africa and Asia. This long-standing geographic isolation has contributed to the distinct anatomical and behavioral characteristics observed in Catarrhini primates today.
• Analyze the social and behavioral characteristics of Catarrhini primates and how they compare to Platyrrhini primates.
  • Catarrhini primates, including Old World monkeys and apes, are generally characterized by more complex social structures and behaviors compared to Platyrrhini primates. Catarrhini species often live in larger, more cohesive social groups with intricate hierarchies and communication systems. They exhibit a wider range of social behaviors, such as cooperative hunting, tool use, and complex problem-solving skills. In contrast, Platyrrhini primates tend to have more simple social structures and behaviors, often living in smaller, less cohesive groups. This difference in social complexity is thought to be a result of the evolutionary adaptations of Catarrhini primates to their Old World environments, which may have favored the development of more sophisticated cognitive and social abilities.

Related terms

Platyrrhini:

The infraorder of primates that includes the New World monkeys, characterized by a broad, flat nose with sideways-facing nostrils.

Old World Monkeys: Primates of the family Cercopithecidae, found in Africa and Asia, characterized by a narrow nose with downward-facing nostrils.

Apes: Primates of the superfamily Hominoidea, including humans, chimpanzees, gorillas, orangutans, and gibbons, characterized by the absence of a tail and other distinctive features.