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🔬general biology i review

Catarrhine

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Catarrhine refers to a group of primates that includes Old World monkeys, apes, and humans. This group is characterized by specific physical features such as downward-facing nostrils and a more complex brain structure compared to their counterparts, the platyrrhines (New World monkeys). The evolutionary history of catarrhines plays a critical role in understanding the broader evolutionary patterns and adaptations within the primate lineage.

5 Must Know Facts For Your Next Test

  1. Catarrhines diverged from platyrrhines around 40 million years ago, leading to distinct evolutionary paths for these two groups of primates.
  2. This group is distinguished by having a dental formula of 2.1.2.3, which means they have two incisors, one canine, two premolars, and three molars on each quadrant of the jaw.
  3. Catarrhines are primarily found in Africa and Asia, whereas platyrrhines inhabit Central and South America.
  4. Many catarrhine species exhibit complex social structures and behaviors, which are believed to be linked to their higher cognitive abilities.
  5. The evolution of catarrhines is closely tied to the development of bipedalism in humans, marking a significant transition in primate evolution.

Review Questions

  • How do the anatomical features of catarrhines differentiate them from platyrrhines?
    • Catarrhines differ anatomically from platyrrhines primarily in their nose structure; catarrhines have downward-facing nostrils that are closer together, while platyrrhines have flat noses with nostrils that are spaced widely apart and face sideways. Additionally, catarrhines possess a distinct dental formula of 2.1.2.3, which contrasts with the dental arrangements typically found in platyrrhines. These differences highlight the evolutionary adaptations that have occurred as these two groups diverged.
  • Discuss the significance of the Hominidae family within the context of catarrhine evolution.
    • The Hominidae family is significant within catarrhine evolution because it encompasses all great apes and humans, showcasing an important branch in the evolutionary tree. Understanding this family allows researchers to explore the shared ancestry and unique adaptations that arose in catarrhines over millions of years. The evolutionary developments within Hominidae shed light on cognitive abilities, social structures, and bipedalism that distinguish humans from other primates in the catarrhine group.
  • Evaluate the impact of environmental factors on the evolution of catarrhines and their adaptive traits.
    • Environmental factors such as climate changes, habitat availability, and food resources have had a profound impact on the evolution of catarrhines. These pressures have driven adaptations like enhanced social behaviors and complex cognitive skills necessary for survival in diverse environments. Furthermore, shifts in habitat led to significant evolutionary changes such as bipedalism in early humans as they adapted to open savanna environments, demonstrating how external conditions directly shaped their physical and behavioral traits over time.