Which group of primates is known as the New World monkeys?

Platyrrhines are indeed recognized as the group of primates known as New World monkeys. This classification includes various species that inhabit Central and South America. Notably, Platyrrhines are characterized by several distinct anatomical features, such as their flat noses which are usually broad with nostrils that are lateral. They also typically possess prehensile tails, which aid them in navigating their arboreal environments.

In contrast, the other groups specified do not fall under the classification of New World monkeys. Tarsiiformes refers to a separate subgroup that includes tarsiers, which are small primates found in Southeast Asia. Catarrhines encompasses Old World monkeys and apes, including humans, and are distinguished by their downward-facing nostrils. Lastly, apes, which belong to a subgroup within Catarrhines, include species such as chimpanzees, gorillas, and orangutans, and they lack tails altogether. Thus, the only correct designation for New World monkeys is Platyrrhines.