Question

Short essay question:

First, discuss the anatomical differences between Paleocene pro-primates and Eocene eu-primates and explain those differences in the context of the three hypotheses for why primates emerged. Secondly, recalling that the genus Carpolestes has been suggested as a transitional animal between proprimates and euprimates, which characteristics of Carpolestes suggests this relationship? Finally, discuss how the Miocene apes’ special characteristics allowed them to travel further than their ancestors did.

Answer 1

Paleocene epoch that existed some 66 to 56 million years ago and Eocene epoch after that about 56 to 34 millions year ago. Obviously, as Eocene epoch was the time period which occurred after Paleocene epoch, so the primates more specifically called euprimates of Eocene had a little developed character than the primates of Paleocene. The characters which were present in Eocene euprimates and absent in Paleocene primates were- increased vision, partially or fully enclosed eye orbits, convergent eyes, small incisors and large canines, nails at the end of digits, mobile grasping digits, short snout , reduced smell and finally the large brain. All these traits pertained to the theory of primate evolution that suggested that primate traits such as grasping hands and binocular vision were adaptations to life in the trees according to Arboreal hypothesis, exploitation of small prey  resulted in the primate suite of adaptations according to visual predation hypothesis and finally  that the primate traits were a response to the development of fruit-bearing angiosperm plants according to the Angiosperm radiation hypothesis.

A second family of plesiadapiforms, the Carpolestidae, is characteristic of Paleocene faunas in North America. It had enlarged incisors, the lower ones simply built and the upper ones mitten-shaped. They had a very small size. Carpolestids have developed their last lower premolars into enormous blades with serrated cutting edges, a condition termed plagiaulacoid that evolved independently in several groups of mammals, most prominently in the archaic multituberculates. They had a vegetarian diet as they had saw like teeth and also had enlarged but flattened and rasplike third and fourth premolar of the upper jaw. The big toe of Carpolestes simpsoni carried a nail, something that allowed to develop far better tactile abilities than if the tip of the toe was covered by a claw. Nails were previously only known in true primates. . Unlike the first true primates, however, Carpolestes shows no adaptations for leaping. By Late Paleocene time, the diagnostic traits of the family are well established in Carpodaptes, and they are further refined in Latest Paleocene species of Carpolestes ("fruit stealer"), the last of the North American carpolestids.

There was a great diversity of ape species in the Miocene, with dozens of species known from the fossil record across Africa, Europe, and Asia.  Nonetheless, we know from fossil and comparative evidence that it was much more similar to living apes than to living humans. These had an ape-sized brain and body, with relatively long arms and fingers and a grasping foot that allowed it to forage in the trees. The canine teeth were probably large and sharp, as seen in several Miocene hominoids. Moreover, the canines were probably sexually dimorphic, with males having much larger canines than females, as seen among the living great apes and Miocene fossils. Like living apes, it would have walked quadrupedally (on all fours) when on the ground, and its diet would have consisted almost entirely of plant foods, primarily fruit and leaves. These characteristics especially the one which says that they were quadruped have allowed them to travel further than their ancestors did.