Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Overview ofPrimate Beginnings65 mya, asteroid hits earthDinosaurs are wiped outMarks the beginning of the Cenozoic EraAt this time, continents are still movingGeoknow.netFirst epoch in the Cenozoic Era is thePaleocene 65-55 myaarchaic primates – unsure whether or not primates(but it seems probable)Plesiadapiforms are primatelike mammalsRecovered from North America, Europe, Asia –that is, from LaurasiaMostly have found teeth and some skullsSmall 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 catPlesiadapiformsCompare archaic primates to prosimiansPlesiadapiforms ProsimiansLack postorbital bar Have postorbital barEyes face out to side Eyes don’t face quite so far to side, more forwardHave rodent-like incisors Have dental comb incisorsHave diastema (gap) No gap between incisorsbetween incisors and and caninescaninesSmaller brain Slightly bigger brainSome have only claws Nails, only grooming clawsCompare prosimians to anthropoidsProsimians AnthropoidsBOTH have prehensile, pentadactyl hands/feetBOTH have clavicles, postorbital barsSome degree of Stereoscopic visionstereoscopic vision, no color color visionEyes face a bit out to sides Eyes face forwardEye sockets not all enclosed Eye sockets enclosed by boneNails, and grooming claws Nails, tactile pads Expanded brainMore emphasis on smell Emphasis on sightLittle sexual dimorphism Have sexual dimorphismEarliest UNDISPUTED primates foundEocene, 55-36 myaThe fact that we have two or three superfamiliesindicates the preceeding Paleocene archaic primatesprobably were primatesIn fact, recent workindicates that by earlyEocene, anthropoidswere already separatedfrom prosimiansBut we lack the fossil recordin Paleocene to prove thisA 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 SciencesEocene, continued 55-36 myaTwo main superfamilies of primates:1. Adapids, which continued as Prosimiansand 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 leapingAdapiformes (Adapids):Lived in North America, Europe, Asia, AfricaThe most primitive group of early modern primates Probably ancestral to present prosimians such as lemurs Dental comb for grooming Some 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.:272Tsjok45.multiplyOmomyids: 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.:272(Eocene 55-36 mya)Middle to late Eocene, to about 36 myaOldest definite anthropoid (non-prosimians)Catopithecus (late Eocene, found in Egypt)By end of Eocene, many prosimians extinct, probably pushed out by anthropoidsAnthropoid characteristics that were new:Diurnal instead of nocturnalLocomotion more quadrupedal instead ofvertical clinging and leapingDiet more herbivorous instead of insectivorousMap showing localities containing Eocene and Oligocene anthropoids.Williams B A et al. PNAS 2010;107:4797-4804©2010 by National Academy of SciencesOligocene, 36-23 myaAge of anthropoids A cooling trend began,and ice cap formed over Antarctica.Continents are drifting away from equatorAt this time, North America and Europe separatedNorth and South America not yet joinedThe Great Rift Valley of eastern Africa formedIndia connected to AsiaAs climate cooled, primates disappeared in thenorthern HemisphereFayum, Egypt a famous fossil localityBack then, it was tropical rain forest(now a desert). Aegyptopithecus found at FayumAmerican primate fossils rare.A Photographic Atlas, Brief Ed., 2005, p.43Oligocene, continued 36-24 myaAmong 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 poundsUnsolved 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 fossilfound in South America dates to 25 mya.But during the Oligocene, South America was at least3,000 km from Africa. At least 200 km between islandsconnecting the two continents:How did monkeys get from Africa, across an ocean,to South America?Hypothesis: they rafted on large mats of vegetationSummary of Major EventsPaleocene - Eocene - Oligocene65-55 55-36 36-24 Continents were not in their present locations65 million years agoDinosaurs were extinctMammal radiationTemperatures were warmuntil OligocenePrimate-like mammals inPaleocene (ex: Plesiadapis)Split between Prosimians &rest perhaps in PaleoceneDefinite primates EoceneSummaryEOCENE: very warm temperatures 55-36 myamammals and primates of modern aspectPeak prosimians, but by end pushed out by anthropoidsTwo groups of primates:1. Adapids, which continued as prosimians2. Omomyids, which became tarsiers and anthropoids Visual Predation Theory to explain development of anthropoid-like characteristicsMiddle to late Eocene, first definite anthropoids(ex: Catopithecus). Fayum, Egypt important fossil localitySummaryOLIGOCENE: cooling trend as continents move away 36-24 mya from equator. Primates disappear in northern hemisphereAge of anthropoids: anthropoids become morenumerous than prosimians; many prosimians goextinctTwo or three families:1. Parapithecid: ancestral to New World monkeys. puzzle: how get from Africa to S. America?2. Propliopithecid: ancestral to Old
View Full Document
Unlocking...