Overview of Primate Beginnings 65 mya asteroid hits earth Dinosaurs are wiped out Marks the beginning of the Cenozoic Era Geoknow net At this time continents are still moving First epoch in the Cenozoic Era is the Paleocene 65 55 mya archaic primates unsure whether or not primates but it seems probable Plesiadapiforms are primatelike mammals Recovered from North America Europe Asia that is from Laurasia Mostly have found teeth and some skulls Plesiadapiforms Small brains prognathic face small eye sockets on the sides rather than front of head no postorbital bar and many have rodent like incisors separated from the molars by a large diastema Some have claws and lack an opposable big toe Range in size from mouse to cat Compare archaic primates to prosimians Plesiadapiforms Lack postorbital bar Prosimians Have postorbital bar Eyes face out to side Eyes don t face quite so far to side more forward Have rodent like incisors Have dental comb incisors Have diastema gap between incisors and canines No gap between incisors and canines Smaller brain Slightly bigger brain Some have only claws Nails only grooming claws Compare prosimians to anthropoids Prosimians Anthropoids BOTH have prehensile pentadactyl hands feet BOTH have clavicles postorbital bars Some degree of stereoscopic vision no color Stereoscopic vision color vision Eyes face a bit out to sides Eyes face forward Eye sockets not all enclosed Eye sockets enclosed by bone Nails and grooming claws Nails tactile pads Expanded brain More emphasis on smell Emphasis on sight Little sexual dimorphism Have sexual dimorphism Earliest UNDISPUTED primates found Eocene 55 36 mya The fact that we have two or three superfamilies indicates the preceeding Paleocene archaic primates probably were primates In fact recent work indicates that by early Eocene anthropoids were already separated from prosimians But we lack the fossil record in Paleocene to prove this A dendrogram of primate phylogeny with Eocene families represented based on cladograms Williams B A et al PNAS 2010 107 4797 4804 2010 by National Academy of Sciences Eocene continued 55 36 mya Two main superfamilies of primates 1 Adapids which continued as Prosimians and 2 Omomyids which became Anthropoids and tarsiers main adaptive shift is from nocturnal to diurnal habit along with shift to more arboreal quadrupedalism and less leaping Eocene 55 36 mya Adapiformes Adapids Lived in North America Europe Asia Africa The most primitive group of early modern primates Probably ancestral to present prosimians Tsjok45 multiply such as lemurs Dental comb for grooming Some nocturnal some diurnal Ate leaves folivores Arboreal Sense of smell Small to medium up to 15 lb Biological Anthropology 2006 Stanford et al 272 Eocene 55 36 mya Omomyids lived in North America Europe Asia Probable ancestor to tarsiers and anthropoids Size of squirrels up to 5 lbs Nocturnal Ate fruit and insects shorter snout Visual predation theory Necrolemur Biological Anthropology 2006 Stanford et al 272 Eocene 55 36 mya Middle to late Eocene to about 36 mya Oldest definite anthropoid non prosimians Catopithecus late Eocene found in Egypt By end of Eocene many prosimians extinct probably pushed out by anthropoids Anthropoid characteristics that were new Diurnal instead of nocturnal Locomotion more quadrupedal instead of vertical clinging and leaping Diet more herbivorous instead of insectivorous Map showing localities containing Eocene and Oligocene anthropoids Williams B A et al PNAS 2010 107 4797 4804 2010 by National Academy of Sciences Oligocene 36 23 mya Age of anthropoids A cooling trend began and ice cap formed over Antarctica Continents are drifting away from equator At this time North America and Europe separated North and South America not yet joined The Great Rift Valley of eastern Africa formed India connected to Asia As climate cooled primates disappeared in the northern Hemisphere Fayum Egypt a famous fossil locality Back then it was tropical rain forest now a desert Aegyptopithecus found at Fayum American primate fossils rare A Photographic Atlas Brief Ed 2005 p 43 Oligocene continued 36 24 mya Among the anthropoids Parapithecid family is ancestral to platyrrhines New World monkeys Propliopithecid family is ancestral to catarrhines Old World monkeys apes and humans Aegyptopithecus 34 mya Fayum 10 18 pounds Unsolved puzzle Parapithecids found in Africa 34 31 mya during the Oligocene are thought to be ancestral to the New World monkeys now found In South America Earliest monkey fossil found in South America dates to 25 mya But during the Oligocene South America was at least 3 000 km from Africa At least 200 km between islands connecting the two continents How did monkeys get from Africa across an ocean to South America Hypothesis they rafted on large mats of vegetation Summary of Major Events Paleocene Eocene Oligocene 65 55 55 36 36 24 Continents were not in their present locations Dinosaurs were extinct Mammal radiation Temperatures were warm until Oligocene Primate like mammals in Paleocene ex Plesiadapis 65 million years ago Split between Prosimians rest perhaps in Paleocene Definite primates Eocene Summary EOCENE very warm temperatures 55 36 mya mammals and primates of modern aspect Peak prosimians but by end pushed out by anthropoids Two groups of primates 1 Adapids which continued as prosimians 2 Omomyids which became tarsiers and anthropoids Visual Predation Theory to explain development of anthropoid like characteristics Middle to late Eocene first definite anthropoids ex Catopithecus Fayum Egypt important fossil locality Summary OLIGOCENE cooling trend as continents move away 36 24 mya from equator Primates disappear in northern hemisphere Age of anthropoids anthropoids become more numerous than prosimians many prosimians go extinct Two or three families 1 Parapithecid ancestral to New World monkeys puzzle how get from Africa to S America 2 Propliopithecid ancestral to Old World monkeys apes and humans ex Aegyptopithecus Oligocene 36 24 mya Among the anthropoids we see the split between Platyrrhines New World monkey lineage Catarrhines Old World monkeys apes human lineage Aegyptopithecus 34 mya Why is Aegyptopithecus seen as catarrhine Dental formula 2 premolars How teeth look How some body bones look Epoch Geologic Time Scale 1 7 mya 5 mya 24 mya 36 mya 55 mya 65 mya Anthropoids proliferate Platyrrhine Catarrhine split Late anthropoids found Undisputed primates archaic primates disputed
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