Primate Evolution

1. A generalized limb structure, including basic pentadactyly and retention of bones often lost in other mammals (e.g. clavicle).

2. Mobile digits, especially the thumb and large toe.

3. Flattened nails and tactile pads occurring at the end of digits.

6. Less emphasis on the sense of smell.

7. Simple cusp pattern of molars and a general reduction in number of teeth.

8. Expanded and elaborated brain, especially the cerebral cortex.

9. Longer gestation and increased vascularization of placental membranes (Primates, 2004).

Primate evolution began in the Cenozoic era, with Lemuroids appearing in the Paleocene epoch, about 65 million years ago.

The major groups of primates come under the Order Primates, which divides into two suborders, the Suborder Strepsirhini (wet nostrils) and the Suborder Haplorhini (dry nostrils) (Haplorhine, 2004; Primates, 2004). Under the Subo

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hine monkeys and hominoids of Africa, Asia and Europe, and the Infraorder Platyrrhini, the platyrrhine moneys of the Americas (Haplorhine, 2004; Primates, 2004). The platyrrhines are also known as new world monkeys because their present day distribution is restricted to South and Central America. The New World MonkeyÆs first appeared in the Oligocene epoch 35 million years ago when South America was an island continent. It is assumed they came across from Africa or North America. The Infraorder Platyrrhini consists of the Family Cebidae, Subfamily Cebinae and Subfamily Callitrichinae, and the Family Atelidae, Subfamily Atelinae and Subfamily Pitheclinae (Haplorhine, 2004). Capuchin and squirrel monkeys belong to the Cebinae. They have semiprehensile tails which they use for additional support but cannot support their entire body weight by their tails and do not have an area of frictional skin on the ventral surface of the distal tip. Capuchins have flexible and muscular backs and short, powerful arms (Primates, 2004). Squirrel monkeys do not have a prehensile tail, and their locomotion is primarily quadrupedal climbing and jumping along the tree limbs and lianas. The Callitrichinae are represented by the marmosets and
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Some common words found in the essay are:
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Approximate Word count = 1685
Approximate Pages = 7 (250 words per page)

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