Essay on Primate Evolution

4605 Words Nov 22nd, 2011 19 Pages
Primate Taxonomy

Primate Taxonomy
Introduction This first lecture is designed to introduce the primate order in terms of its classification and to familiarise you with the animals so that the rest of the course makes some sort of sense. I will cover a working definition of what makes a primate, give you a general classification scheme, describe the major features that identify the groups within the classification and discuss some of the controversial areas of the classification. I shall treat the taxonomy as a synonym for classification which seems to be its commonest current usage, although you should be aware that some people consider taxonomy to be more about the principles behind the classification than the classification itself.
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Figure 4 shows a variety of primate autopodia. Loss of grasping capability in the foot is a feature peculiar to humans.

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Primate Taxonomy Figure 4. Photographs of the autopodia (hands and feet) of a variety of primates. Top left, hand of Pithecia pithecia (white-faced saki); top right, foot of Lemur catta (ring-tailed lemur); bottom left, foot of Pan troglodytes (common chimpanzee); bottom right, foot of Cercopithecus hamlyni (Hamlyn’s owl monkey).

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Primate Taxonomy Replacement of sharp, compressed claws by flat nails; development of very sensitive tactile pads on the digits Figure 5. Photograph of a variety of primate hands showing the presence of flattened nails and sensitive dermatoglyphs. Top right, Trachypithecus obscura (dusky leaf monkey); top left, Callithrix geoffroyi (Geoffroy’s marmoset); bottom left, Pan troglodytes (common chimpanzee); bottom right Sanguinus oedipus (cotton-top tamarin). The two photographs on the right hand side are of Callitrichidae which are the exceptions to the normal primate rule and have claws rather than nails on most of their fingers.

Figure 5 shows a examples of the flattened nails that are characteristic of primate digits and at the same time shows that rules are always made to be broken since in some primates the nail has reverted to being a claw.

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Primate Taxonomy Progressive shortening of the snout Figure 6. Photographs

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