Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14EARLY PRIMATESEocene, 55 myaearliest undisputed primatesWhen do we see the earliest primates?55 myaHowever, we already seesome variety at this time,indicating that primatesbegan earlier despite ourlack of clear fossil evidence65 myaPaleocene, 65-55 myaDinosaurs are extinct; temperatures risingNorth America & Europe pulling apart, islands betweenMajor mammal radiation to fill niches left by dinosaursSome of the small mammals areprimate-like, or primitive primates, or archaic primatesGeoknow.netEARLY PRIMATELIKE MAMMALS,or archaic primates:occur in what became North America and Europe,which at that time were tropical65 mya Montana, primatelike teeth60 mya, Wyoming a few bones example: Plesiadapis PaleoceneMammalsCreationvsEvolutionKnown mainly from North America, but alsofound in Europe and ChinaControversy over whetherprimates or notRange from mouse-size tosmall monkey-sizedAnatomically more primitivethan any living primatePlesiadapis is one exampleearly Paleoceneto late EocenePlesiadapiformsWhy aren’t we sure when the earliest primates appear?1.Incomplete fossil remains (mostly teeth/jaws, some skull fragments)2. Differences among scientists on how to classify: some consider them experiments in becoming primates, but still just primatelike mammalsPlesiadapiforms don’t have even the characteristics of living prosimiansThus, they are called archaic primatesSmall brains, prognathic face, small eye sockets on thesides 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 catPlesiadapiformsERA Period Epoch65 mya55 mya36 mya24 mya1.7 mya(http://www.ucmp.berkeley.edu/cenozoic/cenozoic.html;22 Feb 2005)5 myaGeologic Time ScaleN. America & Asia begin split;S. America & Africa separateGLACIATION: Ice AgeCentral America joins N&SPlesiadapiformsEocene, 55-36 myaVery warm (even in the north); formation of rain forestsClimate change accompanied by replacement ofthe archaic mammals of the Paleocene withmammals of modern aspectLaurasia doesn’t separate until middle EoceneFirst undeniable primates are foundin North America, Europe, Africa, and AsiaThese are prosimian-like, at least 60 generain two main families. Peak of prosimians.Why does everyone agree these are primates?Slightly larger brains than plesiadapiformsEye sockets on front of face (stereoscopic vision and depth perception)Postorbital bar protects the eye socketOpposable big toeNails rather than clawsReduction in snoutEocene, continued 55-36 myaTwo main superfamilies of primates:1.Adapids, which continued as Prosimians, and2. Omomyids, which became Anthropoids and tarsiers:Based on molecular data, it is thought the split between Prosimians and Anthropoids actually took place around 58 mya, during the Paleocene,but we don’t yet have many/good fossils to prove thatAdapiformes (Adapids):Lived in North America, Europe, Asia, AfricaThe most primitive group of early modern primates Probably ancestral to present prosimians such as lemurs Had dental comb forgroomingSome nocturnal, somediurnal. Ate leaves (folivores)Arboreal. Sense of smell.Small to medium (up to 15 lb)Eocene, 55-36 myaBiological Anthropology, 2006, Stanford et al.:272Omomyids: lived in North America, Europe, AsiaProbable ancestor to tarsiers and anthropoidsSize of squirrels, up to 5 lbsNocturnalAte fruit and insects, shorter snoutVisual predation theoryEocene, 55-36 myaNecrolemurBiological Anthropology, 2006, Stanford et al.:272Theory about why primatecharacteristics developed:Visual Predation TheorySearching for fruit and insects on slender branchesfavors vision (especially forward-facing eyes)over smell, grasping hands and feet, andnails instead of clawsERA Period Epoch65 mya55 mya36 mya24 mya1.7 mya(http://www.ucmp.berkeley.edu/cenozoic/cenozoic.html;22 Feb 2005)5 myaGeologic Time
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