Fact 1: The suborder Anthropoidea includes about 145 species. Nearly, 90 percent of the animals in this suborder are monkeys. The rest are humans and apes. Anthropoids are observed as the effective primates on the Earth. They have highly developed eyes and are larger animals. They are also intelligent.
Fact 2: There are two different infraorders of anthropoids which have been evolving independently for a period of 30,000,000 years. These two orders are Platyrrhini and Catarrhini. The former group includes New World monkeys while the latter group includes Old World monkeys. The Catarrhini also includes humans and apes.
Fact 3: The two groups of monkey species are easily identified by looking at the noses and the particular type of teeth.
Fact 4: The nose of Platyrrhine monkeys is flat with the nostrils projecting sideways, and they have a wide septum in-between the nostrils. The Catarrhine’s nostrils are separated by a small septum, and they project below.
Fact 5: All the primates have the same type of mammalian teeth. Every quadrant of the mouth consists of two incisors, one canine, and different numbers of molars and premolars.
Fact 6: Incisors are used for squeezing the food pieces. Incisors function as scissors. The canines are used for tearing the food. The molars and premolars are used for grinding and smashing the food with multiple cusps.
Fact 7: There are three premolars and two or three molars in the Platyrrhine species while the Catarrhine species have two premolars and three molars.
Fact 8: New World monkeys are mostly arboreal, and many of them are smaller than Old World monkeys. Some of the Old World monkeys and apes are semi-terrestrial.
Fact 9: Some of the New world monkeys have prehensile tails which are used as third hands for helping the animal hold on to branches. The tails are also used for hanging.
Fact 10: The Old World monkeys, or apes, do not have the capability of hanging by their tails. Some Old World monkeys have hairless callous pads while New World monkeys do not have them.