Question

The new world monkey differs from the old world monkey in -
(a) Presence of tail
(b) Absence of ischial callosities
(c) Flatter nose
(d) Both (b) and (c)

Answer 1

Hint: The New World Monkeys are also known as platyrrhines and the Old World Monkeys are known as catarrhines. Both of these names define the structure of a particular part of their body. The monkeys are further distinguished from each other by their appearances and the presence of specific body parts.

Complete answer:
- The New World Monkeys are classified as platyrrhines, meaning ‘flat-nosed’ while the Old World Monkeys are classified as catarrhines, meaning ‘downward-nosed’. New World monkeys have a broad nose with a wide septum that separates the outwardly directed nostrils. Old World monkeys have a narrow nose, downward-facing nose, and a thin septum, like human beings.
- The Old World monkeys have ischial callosities that are hard and bare sitting pads present on their hind region, while the New World monkeys do not. This is because Old World monkeys spend more time on the ground while the New World monkeys are more arboreal, they live in trees.
- Both World monkeys have tails, but the New World monkeys have a prehensile tail used for getting food and climbing, while the Old World monkey tails cannot carry out those functions.

So, the correct answer is ‘both (b) and (c) '.

Additional Information:
- There are various other anatomical differences between the Old and New World monkeys.
- Many Old World monkeys have opposable thumbs, hence they can hold objects with dexterity. None of the New World monkeys can do so.
- The “Old World” refers to the areas (Europe, Africa, and Asia) known to the Europeans that were discovered before the “New World” (the Americas) countries.

Note:
- The Old World monkeys belong to the family Cercopithecidae and are related to apes and humans.
- Macaques, belonging to the Old World family, are nearly tailless.
- In New World monkeys, it is common for the males to provide infant care, while in the Old World, it is observed exclusively in females.