Final answer:
The Haplorhini suborder of primates splits into two infraorders: Simiiformes, which includes Platyrrhini (New World monkeys) and Catarrhini (Old World monkeys), and Tarsiiformes.
Step-by-step explanation:
The Haplorhini, which are a suborder of primates, split into two infraorders: Simiiformes and Tarsiiformes. The Simiiformes consist of New World and Old World monkeys, including the superfamilies Platyrrhini and Catarrhini respectively. Platyrrhines, found in Central and South America, are known for their rounded, side-facing nostrils and often prehensile tails. Contrastingly, Catarrhines, located in Africa and Asia, have narrow, downward-facing nostrils. Within the Catarrhini, there are two main groups: the Cercopithecoidea, which encompass cheek pouch and leaf-eating monkeys, and the Hominoidea, which encompasses apes and humans, notable for their lack of tails and largely terrestrial lifestyle.