Final answer:
Old World monkeys are part of the Catarrhini group and possess narrow noses, non-prehensile tails, observable sexual dimorphism, and inhabit Africa and Asia. They have undergone separate adaptive radiations from their New World counterparts and include both arboreal and ground-dwelling species, with superfamilies Cercopithecoidea and Hominoidea.
Step-by-step explanation:
The physical characteristics of Old World monkeys include narrow, downward-pointed noses, a feature that classifies them under the group Catarrhini. Unlike the arboreal New World monkeys with their prehensile tails, Old World monkeys can be either arboreal or ground-dwelling and lack prehensile tails.
Some Old World monkeys have ischial callosities and exhibit sexual dimorphism, with males often more than twice the weight of females. These monkeys, including various species like macaques and baboons, are indigenous to Africa and Asia. In their evolutionary past, common ancestors of monkeys populated Old World regions and later some groups colonized the New World. This led to significant differences in their evolution and adaptations due to the reproductive isolation.
Old World monkeys are part of the Anthropoids' group Haplorrhini, specifically the infraorder Simiiformes which is divided into Catarrhini and Platyrrhini, the latter being the New World monkeys. Differences in physical characteristics are a result of separate adaptive radiations over millions of years. The Old World monkeys fall under two superfamilies within the Catarrhini: Cercopithecoidea and Hominoidea, with Cercopithecoidea comprising cheek pouch monkeys and leaf-eating monkeys while Hominoidea includes apes and humans.