What term describes the flat/broad-nosed primates commonly found in South America?

The correct term for the flat or broad-nosed primates commonly found in South America is Platyrrhini. This group refers specifically to New World monkeys, which are characterized by their wide, outward-facing nostrils and differences in dental structure compared to other primate groups. Platyrrhines include species such as capuchins, tamarins, and howler monkeys, all of which are predominantly located in tropical regions of Central and South America.

In contrast, Catarrhini refers to the group that includes Old World monkeys, apes, and humans, characterized by narrower noses and adaptations to different environments, primarily in Africa and Asia. Prosimians are an earlier subgroup of primates that includes lemurs and lorises, which are not found in South America. Anthropoids encompass a broader category that includes both monkeys and apes, but it does not specifically denote the flat/broad-nosed characteristics related to the South American primates. Thus, the term Platyrrhini is specifically accurate for the flat/broad-nosed primates in question, defining their geographical and anatomical features distinctly.