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fossil table

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memorize!! for test.

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why study fossils?

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- can provide insights about climate, ecosystems, primate communities, evolution of modern characters, behavior relationships

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but what must be keep in mind about these insights:

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- differential preservation of anatomical elements : we have lots of teeth, a few skulls, and sparse post cranial elements for most species - preservation issues : tropical forests are not conducive to the formation of fossils! - fossils cannot provide fine details of behavior. fossils don't have dna. -there is a disagreement among paleontologists about which fossil primates are related and ancestral relationships among groups. Here we try to focus on a very generalized , balanced perspective

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areth through time

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consider: animals already present, resources available, competitors, predators, other lineages were evolving too!, positions of modern continents through time. When we consider the evolutionary timing and history of plants and animals, humans are still new to the scene!

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continental drift through time

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1) Mesozoic Era (251-65 ma): age of dies, first mammals evolve 2) cenozoic era (65-0 ma) : age of the mammals, first primates evolve -- north america, eurasia connected, key to early primate distributions

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earth temperatures through time

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- epochs delineate significant shifts in fossil species represented (extinction events), which correspond with changes in climate / temperature - wer often see adaptive radiations following these extinction events - major primate groups are examples of adaptive radiations

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primate evolution in perspective

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- each epoch in the cenozoic is associated with the adaptive radiation of a major primate group - from here we will examine evolution of each non-human primate group in greater detail in their order of first appearance in the fossil record

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the paleocene

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(65-55 ma) : 1) disosauras had just gone extinct : new niches open for the rapidly diversifying mammals 2) global climate becoming warm and humid 3) N. America and Europe linked 4) mid late paleocene europe and n america were home to warm tropical palm forests 5) angiosperms (flowering trees and plants) becoming more common 6) first occurrence of the plesiadapiforms

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early primate-like mammals : plesiadapiforms

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- arise in the paleocene epoch (65.5.-55.8 ma); most extinct by the end of the eocene - north america, europe, asia - quadrupedal, but well adapted for climbing - diverse in body size and diet preferences - most have diasteme (gap between front and cheek teeth) and claws - no stereoscopic vision

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plesiadapiform : carpolestes simpsoni (55-56 ma wyoming)

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- evidence of grasping hand sand feet, arboreal - divergent hallux (tumb) with flattened nail instead of a claw - did not have stereoscopy, had divergent orbits on the sides of the skull -frugivorous

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where do plesiadapiforms fit into primate origins?

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Purgatorius is generalized enough to be an ancestor of both more derived plesiadapiforms and primates. No clear evidence that plesiadapiforms evolved into primates. Some paleontologists consider most plesiadapiforms to be a sister group to primates, but not ancestral to primates while others believe that an animal like purgatories represents the lineage that evolved into primes.

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why aren't plesiadapiforms primates?

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In their immense diversity, many plesiadapiforms display some primate characteristics, but not have been found to have all of these characteristics or to have a combination of these features that logically leads to the suite of characteristics that typifies true primates

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how do we identify fossil primates

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a suite of physical features: 1) dental similarity generalized, differentiated teeth 2) arboreal 3) grasping hands and feet 4) nails instead of claws 5) forward facing eyes (stereoscopic vision) 6) post orbital bar or closure 7) relatively big brains

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why did primates evolve?

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Major hypotheses for the explanation of primate evolution : 1) nocturnal visual predation hypothesis 2) angiosperm coevolution hypothesis 3) several other hypotheses as well, but most are related to these! These are not mutually exclusive explanations.

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primate origins : nocturnal visual predation hypothesis

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Suggests that early primates required both binocular vision and grasping hands / feet to cautiously and quietly approach insects on fine branches at night. Supporting evidence -- primates have stereoscopic vision, grasping hands...many other arboreal species, like squirrels, do not. Nocturnal inserting hunting is common in small bodied primates.

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primate origins : angiosperm coevolution hypothesis

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Argues that the rise of angiosperms (flowering plants that produce fruits) led to a vast development and broadening of potential food sources. Grasping abilities were adaptations to maneuvering in a fine branch niche and exploiting newly available angiosperm foods including fruits, flowers, insects, and nectars. Angiosperms seem to favor primate dispersal.

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what does carpolestes say about primate origins?

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this early primate like mammal...had grasping hands and feet, but not stereoscopic vision, support angiosperm coevolution, challenges nocturnal visual predation model

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eocene (54-35 ma)

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-Europe and north america connected -by 54 ma primates were present in the warm tropical forests of north america, europe, asia, and africa - angiosperms becoming larger in size and more prevalent

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first true primates: early prosimians

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characteristics of early primates : -stereoscopic vision (more reliant on vision - post orbital bar - snout is reduced - teeth are closer together, no diastema - grasping hands and feet - nails instead of claws - greater adaptations for leaping and more acrobatic locomotion - >200 species!

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the first primates : adapoids

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Leptadapis, an adapted from euorpe: ADAPOIDS : diurnal, body mass 50 g to 10 kg , arboreal quadrupeds, frugivorous and / or folivorous, lemur like, likely ancestral to lemurs and lorises (strepsirhines)

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omomyoids

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rooneyia, an omomyoid from TX : nocturnal, body mass 28 g to 3 kg, arboreal quadrupeds / leapers, insectivorous and /or frugivorous, tarsier like, likely ancestral to anthropoids & tasters (haplorhines)

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early prosimians : early adapoids

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Darwinius masillae, "Ida" 47 ma : -from messel germany, most complete early primate ever found ( outline of hair, stomach contents) - unearthed 20 years ago and hung on wall as art, discovered by science in 2009 - fruit and leaves in stomach - large orbits : probably nocturnal

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end of the eocene epoch ~ 35 ma

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By the end of the eocene, primates disappearing from North america and Europe due to cooling and increasing seasonality as the continents shifted. Polar glaciation occurs. Most of the evidence for anthropoid evolution will now be found in Africa, South America, and parts of Asia.

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oligocene (34-23 ma)

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-increase in woodlands, but overall a global cooling event - primates disappearing from N. Europe and North America - first anthropoid primates appear in Africa, Asia, and South America where the climate was warm, wet, and seasonal - live along prosimians in most places but becoming more dominant by the end of the Oligocene, especially in Africa

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meet the anthropoids!

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- found first in africa and asia, later in south america - diversify into old world monkeys (OWM) and new world monkeys (nwm) - small medium bodied arboreal quadrupeds and leapers - ate fruit mostly, also seeds, leaves, and gums - full post orbital closure and fused mandibles -smaller eye orbits indicate diurnal lifestyle - found alongside already occurring and evoking prosimian groups

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the fayum, egypt fossil locality

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-southwest of nile river delta - on the most productive primate fossil localities ever! - among the primate fossils found: anthropoids, strepsirrhines, tarsiers - elwym simons : father of paleoprimatology

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early anthropoids: apidium

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- an extremely common anthropoid from the fayum depression in N. Africa - 1.5 to 2 kg body mass - fused mandible (an anthropoid characteristic) - 2133/2133 dental formula - possibly ancestral to NWM

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early anthropoids : aegyptopithecus

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- an early anthropoid from the fayum - one of the best known fossil anthropoids -6-8 kg body size - sexaully dimorphic canniness and premolars indicative of one male multi female social groups - 2123/2123 dental formula - possibly ancestral to OWM

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is eosimias an anthropoid?

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Eosimia sinensis : dawn monkey of china (45-50 ma in china) -- 1) unique combination of primitive and derived traits - is it possible that anthropoids actually evolved in the eocene, and not in the oligocene? - some paleontologists believe that these are actually fossil tarsiers. we have too little material to make any definitive allocations.

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another undoubtable anthropoid

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Saadanius hijazenssis (29-28 ma) found in Saudi Arabia in 2009 : closely related to the common ancestor of the old world monkeys and apes

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ancestor or old world monkeys and apes

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eosimias? apidium , aegyptopithecus, saadanius

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the old world monkeys

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- O M W present by 19 may - fossils across africa - cercopithecines and colobines present by 11 may in africa, then in eurasia - diverse diet, size, locomotion - many modern features

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new world anthropoids

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Current evidence points to origin of all anthropoids in the old world. Earliest fossil record of new world monkeys dates to 27 ma, during the late oligocene. Poor fossil record of primate evolution, so we still don't know many things about primate evolution in this part of the world. Then, how did monkeys get to South Ameirca?

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the first new world monkeys (late oligocene 25 -30 ma)

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Branisella and Szalatavus (Bolivia) : - 2133/2133 dental formula - frugivorous - 0.5-1 kg body size : 1) ancestry debated 2) how did they get to south america? The next S. American primate fossils date to several million years later. Branisella is an extinct genus of New World monkey.

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primates in the new world

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Discovery of primates in the new world with dental patterns similar to some old world primates raised questions about the origins of primates in SA. 1) Did neotropical primates evolve conversantly with African and Asian forms? 2) Are neotropical primates derived from North American forms, and then migrated South?. Did Neotropical primates arise from African primates and migrate to South America? This scenario favored by many scientists.

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primate rafting

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One explanation is rafting - floating island that contained primates made the trans-Atlantic trip. Evidence of raft from Africa : 1) no early anthropoids have been discovered in North America 2) new world fossils show close similarity to African anthropoids such as APidium 3) evidence of rats rafting from Africa

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The Miocene (23-5 ma)

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- world temperatures warmed after the cooler Oligocene, with minor fluctuations in temp throughout the epoch - early and mid miocene characterized by dense tropical forests, then by the late miocene there is an increase in savannah like grasslands in Africa - continents in the old world were roughly in their modern positions - adaptive radiation of OWM and apes ramps up towards the end of the miocene

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the miocene apes

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1) Apes diversify in Africa and Eurasia 2) early miocene : many relatively small "dental apes" with monkey-like skeletons but ape-like teeth 3) late miocene : apes become extremely diverse! - most species have no living relatives - more ape species than monkey species 4) ancestors of modern apes - it's not clear which species are ancestral to each modern ape genus

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miocene ape: proconsul species

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Proconsul species: 21-14 ma, African, 17-50 kg body size. Transitional form from early generalized anthropoid to modern ape. - post cranial anatomy - skull and teeth

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post cranial anatomy

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monkey-like, intermembral index more similar to monkey than an ape, no tail, quadruped that lived in the trees, not suspensory

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skull and teeth

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-ape-like, skull and teeth are more like an ape, fed on fruit

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miocene ape: sivapithecus

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Sivapithecus : 14-7 ma, Asia (Pakistan). Skull and teeth look very similar to modern day orangutans. However, arm bones are different than living orangutans. Conclusion: closely related to, but not direct ancestor of orangutans.

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Gigantopithecus: the real "Big foot"

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- probably derived from Sivapithecus -first appears in late Miocene of Asia (India, Pakistan), common thru mid-Pleistocene (China, Vietnam) -up to 300 kg! - thick enamel and low, flat cusps folivore with fruit consumption -likely terrestrial due to size - largest primate ever! - bipedal? no actual proof but it has been speculated - co-existed with homo sapiens

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more miocene apes

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1) drypithecus : 14-7 ma, Europe 2) Ouranopithecus : ~ 8 ma Europe. Both European, relatively large bodied apes. Brain case and face shape similar to African apes. Might be ancestor of African apes and humans.

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hominoid evolution

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We start of the Miocene with animals that are essentially monkey-like. By the late Miocene, we see many modern Hominoid traits : - modifications to the shoulder and arm (brachiator anatomy) - lack of a tail - larger body size (on average) -larger brain size relative to body size -low, rounded molar teeth (with a tooth morphology called Y-5 molar pattern. Early hominoids had a combination of monkey like traits with derived, ape like traits.

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primate origins (miocene epoch 23-5.3 ma))

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Early and middle Miocene characterized by dense tropical forests in Africa. Europe, Asia , Africa, and South America.

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Europe

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Dryopithecus (10 ma) and Ouranopithecus (9 ma) hominoids

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Asia

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Sivapithecus (9 ma), hominoids flourish in the middle to late miocene

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Africa

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diverse radiation of large and small hominoids until late miocene

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South America

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diverse anthropoid radiation in southern regions of south America

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possible relationships among fossil and ....

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extant anthropoid primates

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primate origins : hominoids to early hominins

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Hominoids spread widely throughout the southern latitudes of Europe and Asia. Indication of migrations back and fourth to Africa. Apes which may have been ancestral to pongids and humans are present. After the middle of the Miocene, hominoid diversity dwindles...few fossils from between peak of apes and emergence of humans.

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hominin

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humans and their ancestors since the divergence from the common ancestor with chimps and bonobos

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evolution of miocene apes: the genetic evidence

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Not able to precisely identify the common ancestor of African apes and humans. We have genetic information about Miocene evolution..or at least the date of divergence of humans from African apes.

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