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What is the Evolutionary History of the Primates?



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What is the Evolutionary History of the Primates Cenozoic Timescale What is the Evolutionary History of the Primates 1 EOCENE 54 38 mya Prosimian Radiations 2 exs Smilodectes Necrolemur 2 OLIGOCENE 38 23 mya Monkey Radiations 2 exs Apidium Aegyptopithecus 3 MIOCENE 23 5 mya Ape Radiations 2 exs Sivapithecus Gigantopithecus Sahelanthropus Late Cretaceous Primate like Mammal Purgatorius Last Common Ancestor lived sometime in the late Cretaceous when dinosaurs still dominant land dwelling life form genetic evidence diversity of primates from the Eocene and later However fossils of true primates are not known until approximately 50 mya during the Eocene During the late Cretaceous 65 mya ancestral shrew like mammals show certain dental and limb bone features reminiscent of true primates Primate Origins If the last common ancestor of living primates did indeed live between 80 and 90 mya the primate lineage that we are descended from would be pushed back more than 30 million years New Discoveries of Early Primates New discoveries from Eocene of China reveal an unexpected diversity of early primates Some ancestors of monkeys apes and humans were so tiny that they could have stood atop a person s thumb Fossilized foot bones from 2 species smaller than any other known creature on the primate family tree were found at a limestone mine in Eastern China bones each about the size of a grain of rice Eocene Primates Prosimian radiations 1 Smilodectes North America Like modern lemurs it was hind limbed dominated indicating ability to leap long distances had hands feet w nails had supple flexible spine Unlike modern lemurs it had generalized dentition lacking toothcomb but retained large canines had fused lower jaw shortened muzzle Eocene Primates 2 Necrolemur Europe Very similar to the modern tarsier Its features included Elongated ankle bones similar to those seen in Tarsius indicative of clinging leaping Reduced snout and enlarged orbits indicative of nocturnal adaptation More



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