Human Origins Final

11. I put several fossil finds under the heading of "surprises, flat faces, and trouble makers." How many of these can you recall including their time range and location. Critically, how to they affect our interpretation of human evolution during the Plio-Pleistocene?

****know 2 for test. Name, date, location, nutshell fact. Australopithecus bahrelghazalia. 3.5-3.0 mya. Central africa. Resembles Lucy the most (perhaps she had wide-spread relative?) Kenyanthropus platyops. 3.5-3.2 mya. East africa. Is this an entirely different lineage, or still considered australopithecine? Australopithecus garhi. 2.5 mya. East Africa, Ethiopia. Odd combo of prognathic face and huge molars. Tool-using. Australopithecus sediba. 1.98 mya. South africa. Small brain, twisted bipedal walk, human dentition. All of these fossils show us an incredibly diverse range of hominins in the plio-pleistocene, many of which do not fit neatly into categories, and some of which cause a lot of debate as to which genus they should even be in. It raises problems with primitive retentions (arms still longer than legs). Another issue is if the exhibited bipedalism is a hypotheses leaning more towards the refinement of bipedalism rather than the origin of modern bipedalism. All species show specializations according to their environment, also shared derived traits that allow them to form a clade. But this could also be parallel evolution. Ultimately, interpretations are still debated and unclear.

3. What features suggest that Au. afarensis was a habitual biped? What features raise questions about this? Where do you stand?

-Au. afarensis had a non-opposable hallux (big toe) and human-like arch, as proved by the Laetoli footprints. -The position of the foramen magnum (the opening in the base of the skull through which the spinal cord passes) is inferior and more medially placed (towards the middle) in habitual bipeds (meaning the spinal cord is more vertical, as well as the cranium), whereas quadrupeds have a foramen magnum that is more ventral or posterior (towards the back of the skull, with a spinal cord parallel to the ground, as well as the face) - Au. afarensis has five or six relatively larger lumbar vertebrae. Humans usually have five that are larger than those of afarensis (but close), and chimps have 4 lumbar vertebrae that are relatively smaller than both humans and afarensis. Both afarensis and humans also have a lumbar curve, the curvature of the lower spine. This increase in lumbar size, number, and curvature helps facilitate biped walking because the more flexible the lower vertebrae, the more weight may be put on the pelvis from upright walking, allowing the hips and trunk to swivel forward when walking as opposed to awkward, large, and more roughly angled hip swiveling (like walking with really heavy feet) in chimpanzees who walk occasionally in this disjointed bipedal fashion. - The sacrum (triangular bone fused below the lumbar vertebrae) is wide and short in both humans and au. Afarensis, whereas in quadrupeds the sacra are long and narrow. - The ilium (pelvis) in humans looks similar to a wing, as it is curved. This curved ilium is called an ala. Humans have a large pelvic outlet (large hole in the middle of the pelvis) that allows for large-brained infants - Lunate sulcus in more posterior position (though debated still)- the lunate sulcus in humans is commonly not clearly discernable because we have a super-expanded parietal cortex, but when it can be discerned, it is in a post-parietal position, with it nearing the occipital pole (the furthest extension of the occipital lobe). Au. afarensis points to having a posterior lunate sulcus, opposed to the anterior position of the lunate in chimpanzees. Having a lunate sulcus in a mostly posterior position is an autapomorphy (a distinctive feature, known as a derived trait, that is unique to a given taxon) to humans, meaning that a posterior lunate sulcus is unique to the human lineage, not to side-branching taxa. The position of the lunate sulcus is much debated, especially at Columbia, where famous Neuropaleologist Halloway is at the forefront of the argument in favor of a posterior lunate sulcus in afarensis.

5. What skeletal features differentiate Au. africanus from its earlier relative, Au. afarensis? [When I ask about skeletal features think about the full range--overall skull, dentition, postcranial skeleton, brain. Don't worry about the specifics of brain size too much, a broad range of 400-550 for all australopithecines is enough. In truth, I view that and height/weight as sprinkles/extras so focus on the core data.] Africanus has:

1. Smaller, rounder skull 2. Less prognathism 3. Cheeks aren't as swept back (which is directly associated with prognathism -- less prognathism, less distance between cheeks and mouth) 4. Flexed Cranial Base (A flexed cranial base provides a face that edges towards the front, with the eye sockets and cheekbones moving to a more unilateral position, whereas an unflexed cranial base provides a face with cheekbones being swept back, resembling prognathism in chimps) 5. No C/P3 complex 6. Molars and Premolars increase in size 7. Thicker jaw with thicker enamel 8. CLEAR change in diet due to molar and premolar increase 9. Shorter, deeper face in general (see 3, 4) 10. Pelvis curved much more than Lucy's (see ilium ala above), meaning it is more evolved for bipedalism 11. Toes not curved 12. No sagittal crest

Last of the Neanderthals (Hill):

140 bones found in El Sidron cave surprisingly turned out to be murdered neanderthals from 143,000 yrs ago. Cuts on the bones point to cannibalism. The interbreeding debate is discussed from both sides. Did AMHs survive because they were just smarter? Cannibalism helped the remains be more helpful for today's biologists. The new finds possibly suggest capability for human language despite Neanderthals being a separate species from us. New data from teeth points to a shorter time before adolescence/mating —> society as a cultural buffer. Longevity —> culture of innovation. Story of Neanderthal disappearance is probably different in every country/place and they probably did not have much contact with AMHs.

7. What are the four families of anthropoids from the Fayuum presented in class? Can you name a species from each?

2 Stem/Basel Anthropoid families: Protopithecede Example: Protepithecedeus 2.2 lbs 2133 dentition Parapithecede Example: Parapithecedeus 2.2 lbs 2133 dentition 2 Stem/Basel Catarrhine families: Oligopithecede Example: Oligopithecus Smaller 2123 dentition Propiopithecede Example: Propiopithesis Bigger (13-18 lbs) 2123 dentition

4. Where has H. habilis (sensu lato) been found? What is the date range for this taxon?

2.4 mya in South Africa

First of our kind (Wong):

A. sediba is a fossil found in S. Africa, that its finders think could prove that early hominids evolved not in east Africa, but S. Africa. Other researchers are skeptical, saying the form is too different from H. Erectus for it to be its direct ancestor, especially at the age it was dated. They feel that the hominids of S. Africa were a separate radiation that ultimately died out. The skeleton also suggests that you may need a more complete skeleton to be able to make inferences about a taxa, since the sedona skeleton contains bones that look so different, if they were found in isolation they may have been assigned to completely different genus. The find may also offer other insights. It is possible traces of skin and tarter were left on the fossils, which would allow a much more complex understanding of things like the taxa's diet, sweat gland arrangement, even their DNA.

4. What are the two broad categories of primate forms found in the Eocene? How do they differ? It is fine to use a general statement but then support the aspects of the general statement with evidence from morpholology (e.g., if you say that one was gregarious, what would be the proof?)

Adapids and Omomioids Adapoids Found in North America, Europe, Asia, possibly Africa Diurnal-smaller eyes Frugivores and folivores-wide incisors Gregarious-sexual dimorphism Predominantly arboreal quadrupeds w/ some vertical climbers Larger legs than arms Larger that omomioids Ring-like ear Omomioids Examples: Rhumea, Omomious Nocturnal Insectivorous-sharp spiky molar cusps Solitary-low sexual dimorphism Vertical clingers & leapers Smaller snout

Made in Savannahstan (Kohn):

Articles discusses an excavation side found in Dmanisi, Georga where five hominin skulls were found. "Out of Africa" theory predominant for a long time-rooted in romantic notion that what makes us human was what propelled us to leave Africa and explore the rest of the world. Earliest remains of h. Erectus remains in Africa are 1.8 million years old. Commonly thought that H. erectus didn't migrate to Asia until about 1 mya, but recently H. Erectus tools dating back to as far as 1.8 mya have been found in Indonesia. H. erectus remains were also found in Chad, and there is no reason why they wouldn't have colonized the Red Sea region from there. Additionally, Africa's Savannah-like climate extended well into Asia-a region which Kohn names "Savannahstan". If H. erectus thrived in this climate, why would they have made a distintion btw. Africa and Asia when choosing where to settle? These findings suggest that hominins migrated from Africa as either Australopithecines of H. habilis. The hominin skulls in Dmanisi may have been H. habilis or Australopithecines due to their small stature. Their skulls suggest morphological changes developed to adapt the cold. They may be a key link in the evolutionary history of h. Erectus.

8. Based on your assessment of Au. afarensis and Au. africanus and the "robust" forms, what aspects of the environment and/or diets of these species may explain their distinct cranial and dental morphology?

Au. afarensis and Au. africanus are considered gracile forms, staying in the Australopithecus genus, and boisei, robustus, and aethiopicus are robust forms, with a debated Paranthropus genus. The robust forms have much thicker teeth, large sagittal crests (for muscle attachment for chewing), thicker jaws, and have changed diets. Because the robust forms are more adapted to be hard-object feeders, it seems they didn't dominate the variation in food as did the gracile forms. Where gracile forms were in savanna territory, the robust forms weren't, relying on hard plants to survive.

1. For each of the early hominins discussed so far "our familiar friends" try to give the full name, the area where found (EA, SA or CA) and the time range--including the alternatives.

Australopithecus Afarensis EA 4.0/3.9 --------3.0 mya Australopithecus Africanus SA 3.5/3.0-----2.5/2.0 mya Australopithecus/P Aethipocus EA 2.8/2.6 --------2.2 mya Australopithecus/P Boisei EA 2.3------------1.2 mya Australopithecus/P Robustus SA 2.0 ------1.5/1.0 mya

2. What do Au. and P. stand for when written for the genus name?

Australopithecus and Paranthropus

2. How do the Lomekwian stone tools impact our understanding of human evolution? (I'm just curious for your thoughts about this. These finds are still new and researchers are trying to answer this question for themselves. Think about what you've read in terms of non-human primate tool use and how this is consistent with or departs from what is seen in living non-human primates. There is no right or wrong answer)

Because these tools date back 3.3 million years — older than any other tools discovered — the find suggests that tool making arose with australopithecines. This means that tool-making ability were possible even before the Homo, so earlier forms had more potential for "human like" behavior than we may have thought.

2. What are the three broad trends that we use to distinguish the early hominins whom we know well ("our familiar friends") as hominins and not just as other hominoids? Discuss each trend.

Brain: a small increase in relative brain size and potential reorganization Dentition and Diet: Relative decrease in anterior dentition; relative increase in posterior Limbs & Loco: modifications towards bipedalism

14. Discuss four contrasts in skull form between the "Asian" and "African" Homo erectus (sensu lato).

Brow African Forms: thinner, curved brow ridge Asian Forms: thicker straighter brow Slope African Forms: less sloping forehead Asian Forms: more sloping forehead (receding) Keel African Forms: No sagittal keel Asian Forms: Sagittal keel Angle African Forms: Rounder, less angled skull Asian Forms: Skull has strong angle

Primate origins nailed (Sargis):

Carpolestes is from the late Paleocene epoch (65 to 55 mya). It has a grasping foot that shares several features with that of modern primates (euprimates), including an opposable big toe with all nails rather than any claws. It could probably grasp with its hands as well. These features allowed Carpolestes to move in the trees where fruit is. Originally considered a plesiadapiform, with new skeletal discoveries the Carpolestes looks closer to euprimates, perhaps an ancestor.

4. How does Homo habilis (in the broad sense) differ from the australopithecines? [Think about the broad categories of overall appearance of the skull, postcranial bones, brain, etc.]

Changes in BRAIN: definite increase in size (20%) ---> 500-800 cc, definite reorganization Changes in DENTITION: even out in sizes of teeth ---> getting there, larger incisors and canines, smaller premolars and molars. Parabolic dental arcade, not as much as ours but getting there NO changes in POSTCRANIALS: no clear change, foramen magnum centered, arched foot, large ankle, non-divergent big toe, arms > legs still Changes in STONE TOOL MANUFACTURING: marks a change in lifestyle. Oldawan stone tools=beginning of human tool use Changes in SKULL: higher/rounder brain case, less prognathic. NEVER buttressed or dish-shaped

1. What can we say/hypothesize about the lifestyle of most of the australopithecines and even the paranthropines in terms of diet and general adaptation to their environment?

Changes in locomotion and postcranial build suggest modifications towards partial/habitual bipedalism Bipedalism means the freeing of hands for tool use. Tool use was rare and not systematic. Changes in dentition suggest a broader diet—SMALLER ANTERIOR, LARGER POSTERIOR: relatively flatter molars, semi-sectorial P3, reduced CP3 complex (but they still have one). Smaller insicors and canines, a shift towards a parabolic palette. Molars have a tiny second bump, meaning a shift towards human bicuspid teeth. Changes in brain mean they are thinking differently. Small relative increase in brain size means possible reorganization.

8. What are the ecological changes in the Late Miocene and how does this affect hominoids?

Climate change involving the combined effects of Alpine, Himalayan and East African Mountain building, shifting ocean currents, and the early stages of polar ice cap formation lead to stabilizing temperatures across Europe, the birth of the Asian monsoon cycle and the desiccation of East Africa. Most of the Eurasian great apes went extinct as a result of the extreme climatic changes. Two lineages did persevere: the Sivapithecus and Dryopithecus, and did so by moving south into the African tropics and Southeast Asia from Europe in response to a drying and cooling of the rainforests into grasslands and woodlands. Adaptations to life on ground - knuckle-walking - were critical in enabling the lineage to withstand the loss of arboreal habitat to make it to Africa.

5. What happened to the climate at the end of the Eocene/beginning of the Oligocene and how do you think that the ecological and geological context of the time affected primate evolution?

Cooling, great cut, less fruit, more prairie-like terrain. Animals that survive can chew harder things, more efficient chewing.

6. Pick one other method that doesn't fall into the "relative" dating methods category and discuss it to the extent presented in class.

Dating based on Mitochondrial DNA is based on the principle that a mutation arises in mitochondrial DNA every million years, changing 2-4% of the DNA sequence. By comparing two strands of DNA, you can isolate the last common ancestor.

4. How many methods in the other category of dating methods can you name?

Dendrochronology, isotopic/radiometric methods, Electron-trapping techniques (TL, OSL, ESR), mitochondrial DNA.

Twilight of the Neandertals (Wong):

Discussion of a . Two contrasting views: one posits that Neandertals were assimilated into the homo sapien species, the other posits that Neandertals were quickly extirpated when humans moved into their territory. However, evidence suggests that when homo sapiens moved into Europe about 40,000 years ago, they existed alongside for about 15,000 years. Explanation for Neandertal extinction: climate went through extreme oscillations in the OIS-3 period, meaning that a climate could change completely within an individual's lifetime, forcing them to dramatically alter the way they lived/hunted. When humans started moving into Europe, Neanderthals were forced to compete for resources. Ultimately, because of the small advantages that humans had over Neanderthals, such as division of labor between women and men, a smaller required caloric intake, a longer lifespan allowing for an increase in reproductive periods and increased time over which to acquire specialized knowledge, and advanced tailoring skills allowing for warming clothing, humans won out.

10. Where do researchers think that the last common ancestor of the African great apes came from? Can you name a candidate from each of the two broad areas?

Dryopithecus - some position as ancestor to Asian apes while others positions it the ancestor to all living apes. It grew out of Europe. The other candidate is the Sivapithecus from Asia and most likely the forebear of the orangutan.

2. What are the three possible options as to which stock gave rise to the anthropoids? Which do you think is accurate and why? (there is no "correct" answer to this; experts in the field disagree).

Either adapoids, omomioids, or something else.

8. What is the morphological evidence for the conclusion that two of the families are considered stem/basal anthropoids while the other two are considered stem catarrhines?

First two have a platyrrhine dental formula, second two have cattarhine dental formula.

1. What are the various steps that an organism might go through from burial to discovery as a fossil? What factors might help in the fossilization process, what factors might hinder it?

First, burial. River deltas, sediments, and caves are good places for preservation. The faster the burial, the better. May be cover with varying layers of volcanic material or sediment. May be excavated intentionally by humans or by animals seeking food—as a result, the edible parts rarely remain. Unintentionally by quarries, construction sites, etc. Processes of erosion include flash floods, natural disasters, strong wind patterns. Fossilization occurs when the inorganic replaces the organic; the higher the mineral content of a specimen, the better chance at preservation. Erosion, squashing, cave collapses. Found more often in sheltering locations, as discussed in "The Youth, Stone Dead."

3. Describe the appearance of Purgatorius (or of plesiadapids in general)

Flexible, mobile wrists and ankles suggest a small arboreal creature; its low rounded molar shows signs of frugivory. No post-orbital bar, sideways orbits, no petrosal bulla. Claws, not nails. Non-opposable digits. Rodent-like incisors. 65 mya.

5. Where were H. habilis (sensu lato) fossils found? When did it live? For the latter, you can give the date from your text or the timing based on the recent find.

Found in South and East Africa. Subsequent finds pushed the timeframe back to 2.4-1.4 mya. Recent find dates it at 2.8/2.75 mya—if he is h. Habilis, it would push the timeframe back even further.

6. What traits help us to distinguish anthropoids?

Fused mandible, frontal, post-orbital closure, slightly larger bodies with increase in brain size and complexity decrease in snout, forward orbits, increased reliance on vision.

Interbreeding with Neandertals (Zimmer):

Geneticist David Reich studies mitochondrial DNA-a form of DNA that changes very little when passed from mother to child-to challenge the "Out of Africa" theory of early human migration. Through analyzing mitochondrial DNA, Reich is able to trace all humans back to one common ancestor, or a "mitochondrial Eve", who lived in Africa about 200,000 years ago. He uses similar techniques to map out the Neandertal genome, and by doing so is able to reveal that European and Asian populations occasionally intermingled and interbred, resulting in Europeans and Asians having 2.5% Neanderthal DNA on average. This incredibly small amount-merely suggesting that a Neandertal and a human only had a child once every 30 years-can possibly be explained by mankind's tendency to avoid the "other". Zimmer ends his discussion of Reich's findings with a discussion of the Denisovans, another early hominin population whose DNA can be seen within populations in Papua New Guinea and aboriginal Australians.

11. Where has H. erectus (sensu lato) been found? What is the date range for this taxon in Africa? In other parts of the world?

H. erectus has been found in East, North and South Africa, Asia (Java, China, and India), in Eastern Europe and possibly even in Israel, though the major finds have been in Africa and Asia. African forms are dated 1.8 MYA-1 MYA, while Asian forms are dated 1.8 MYA- 100,000/53,000 BP

18. What kind of tools did H. erectus use (sensu lato)? Discuss the tradition, technique, characteristic tool(s), and cultural period. Were the tools the same throughout all the areas in which H. erectus fossils were found?

H. erectus in Africa associated with the Achulean tool tradition, dated at 1.76 MYA- 200,000 BP. The technique begins with hard hammer percussion, but also uses soft hammer percussion. The characteristic tools are handaxes, cleavers, and retouched flakes. This tradition is within the lower paleolithic cultural period (2.7 MYA-200,000 BP). In Asia H. erectus has been found using mainly Oldewan tools but at one sight handaxes have been found so we know they were capable of making them.

12. What are the morphological differences in the cranium and dentition between H. habilis (sensu lato) and H. erectus? (sensu lato). Are there any differences in postcranial anatomy?

H. habilis has dentition that is evening out (anterior dentition getting larger and posterior getting smaller), but it doesn't overlap human range until H. erectus. Erectus also has shovel-shaped incisors, which habilis does not. In term of skull, erectus retains the decreased prognathism of habilis, but gains an occipital torus and strong occipital angle, a long, low braincase (as opposed to the high rounded skull of habilis), a sagittal keel, thick brow and bones, a sloping forehead and a max. Width that ies low on the head. Both show brain reorganization, with erectus having a basic modern human brain plan. In terms of post-cranials, with erectus we finally get legs longer than arms and a human striding gait that were not yet fully developed in the bipedal, but not as elegant habilis.

9. What kind of tools are most closely associated with H. habilis? Can you name the tool tradition, technique, characteristic tool and cultural period to which they belong? What does this suggest to us about their lifestyle—how do we think that they were used?

H. habilis is associated with the oldowan tool tradition, dating around 2.6 MYA. The technique is hard hammer percussion, in which a hard is used to make flakes from a softer stone. The characteristic tool is the core/chopper and the resulting unretouched flakes. These tools are associated with the lower paleolithic cultural period. These tools suggest that H. habilis were scavengers and used the choppers to get marrow out of long bones from leftover kills. This changes the image we once had of them as hunters, as it seems very unlikely they would be able to take on big game with only choppers and flakes.

7. How does the cranium of Au./P. aethiopicus, commonly referred to as the black skull, differ from those of Au./P. robustus and Au./P. Boisei

Has a much larger sagittal crest, with a compound crest present (compound found in neither boisei nor robustus) Is much more prognathic Has an unflexed cranial base Upper dental arcade converges toward back Large Incisors Temporalis muscles angled more in back, like Lucy However, foramen magnum is more centered

5. Who is Carpolestes simpsoni and how/why did he change some views about plesiadapids?

Has a petrosal bulla, a grasping toe, nails not claws. 56 mya. Ankle proves arboreal living

9. Given you analysis of all of our "familiar friends", what is your opinion as to the phylogenetic relationships among these forms—that is, do the robust taxa form a clade and warrant a different genus name or is this a case of parallel evolution? Explain your reasoning in full.

I believe the robust taxa form a clade, as their traits seem to be distinguished from the gracile forms which seem to be what gave rise to Homo, or at least are a distinct line that perhaps share a common ancestor with Homo. Because their diets were so varied, I believe their brain structure to be different, as well. The genus Paranthropus is based primarily on craniofacial morphology that suggests an adaptation to feeding on hard or abrasive foods. These features include postcanine megadontia, thick enamel, and changes to the zygomatic and other cranial bones that result in an improved mechanical advantage for chewing on the postcanine tooth crowns. If these adaptations of the megadont archaic hominins were inherited from a recent common ancestor, then a separate Paranthropus genus is justified; however, if they occurred independently in the P. aethiopicus and P. boiseilineage in East Africa and in the P. robustus lineage in southern Africa, and thus were examples of homoplasy, then a separate genus would not be justified

1. What is the difference between dating fossil finds from East Africa and those from South Africa?

In South Africa, most of the preserved fossils are found in limestone caves. Limestone is perfect for bone preservation, but horrible for dating (lithostratigraphy, cosmogenic nuclide stratigraphy) South Africa is considered to be a savanna-woodland mosaic at the time of Australopithecines, which would promote more bipedalism (open distances in savanna mean more to travel, varied diet, meaning bipedalism would be favored). East Africa is considered a primarily woodland environment at 3-4 mya. In East Africa, the Great Rift Valley is a hotspot for fossil finds, as it is the border of a tectonic plate with high volcanic activity and ash (perfect for dating). Tectonic movement in the Miocene and Pliocene caused the Eastern ⅓ of the continent to become elevated, creating the ridge of the Great Rift Valley and promoting savana creation.

4. Based on your analysis of the skull, does Au. afarensis look more like a modern human or a chimp? Why?

In terms of dentition: The chimpanzee has large incisors and relatively small cheek teeth (P3 to M3) -- Its canine is large and pointed. In afarensis, the cheek teeth are much larger but the incisors are smaller. The canine is also smaller, though still somewhat pointed and projecting. Afarensis maintains a C/P3 complex, but it does not project nearly as much as in chimps and is only semi-honing (semi-worn/fitting). Its teeth are thicker than in chimps, and flatter. In modern human beings, the whole dentition is much reduced, and the canines scarcely project at all. The dental arcade is intermediate, but closer to the parabolic dental arcade seen in humans, even converging towards the back. The temporalis seems to be angled posteriorly, as it also is in chimps; however, the sagittal crest and nuchal muscles/crest touch on afarensis, meaning it has a smaller brain case while largely increasing chewing force. Chimps don't have as prominent a sagittal crest, and humans have none at all. In sum, afarensis is a transitional, with many traits resembling chimps and many resembling humans. I believe the changed dentition in afarensis, along with the placement of the foramen magnum to a more lateral and medial position indicates that afarensis had a diet very different from chimps, also meaning it had a changed behavior in searching for foods (see lunate sulcus placement discussion above) and changed locomotion, bipedalism. However, in terms of facial recognition in comparison to chimps, Lucy is very much more prognathic than humans, and her canines do project, making a first glance seem wholly chimp.

4. What happens to hominoids in the Middle Miocene in Africa? Who appears, who disappears, and how is this connected to changes in climate? Can you name one of the forms that appears and how he may be adapted to this changed climate?

In the middle Miocene around 16.5 million years ago, global sea levels dropped exposing a land-bridge to Eurasia. Early Miocene Apes left Africa because of new adaptations in their jaws and teeth that gave them a freedom to explore a variety of ecological settings. Some primitive apes returned to Africa but there is generally a gap in fossil record between early and late miocene - 17 to 15 mya - concerning hominoid evolution in Africa. The Kenyapithecus is a Middle Miocene form circa 14 mya. The adaptations in craniodental features to hard objects can be linked to the change in climate in Africa. Robust jaws, thick enamelled teeth indicate a hard fruit diet. Also adaptations to knuckle-walking suggest reduction in rainforest in Africa? There is literally no info on this anywhere.

4. What features from your description led some researchers to hypothesize that this was an early primate? What primate features were lacking in this form that led others to reject that hypothesis?

Its hands (claws/non-opposable), lack of postorbital bar, and incisors suggest it is a non-primate, but its other teeth (molars) suggest primate.

2. What can you share about the geological and ecological context at the time that the earliest primates are believed to appear (65-90mya)?

K/T boundary—angiosperms radiate and so do insects and insectivores, including birds and mammals.

Can you name at least one taxon from this time? Using news articles/text/required article from the syllabus, describe this taxon in a haiku.

Late Miocene ape, the Oreopithecus is associated with suspensory locomotion, including a relatively short trunk, long arms, short legs, long and slender fingers, and great mobility in all joints. It is proposed that the Oreopithecus was able to walk bipedally along tree limbs and had a humanlike hand capable of precision grip... a generally highly suspensory animal.

3. For each of the five "relative" dating methods presented in class, state the name and discuss the method (to the extent presented in class).

Lithostratigraphy involves dating the fossil based on different layers of rock and sediment ("tuffs"). Tephrostratigraphy compares layers of volcanic ash across regions. Biostratigrpahy uses other animal specimens for whom we know rough time periods to date fossils found beside them. Includes vole clock. Paleomagnetism—rocks orient themselves toward the magnetic pole, which reverses every 700,000 years. This is a calibrated method so you can get an exact date. Flourine-dating measures the amount of fluorine found in bones compared to other bones—bones absorb fluorine from water.

5. What happens to hominoids in the Middle Miocene in Europe and Asia? How is this related to aspects of both ecology and geology (for the latter, plate tectonics)? Can you name some of the taxa that appear at this time?

Most earlier Miocene apes went extinct in the forests of Eurasia for not having adequate dentition to eat harder foods or remove the durable husks from some tough foods. The new ecological conditions in Eurasia drive speciation and diversity. Throughout the Middle Miocene, great apes flourish thanks to the lush subtropical forest cover and consistently warm temperatures. The conditions made ripe fruits readily available and the habitat was very easily traversible. Homonoids began evolving modern cranial and dental features in Eurasia and then returned to Africa to adapt into even more advanced species, only after sea levels dropped again. Early Eurasian great apes, isolated from Africa by elevated sea levels radiated into a multiplicity of forms due to the combined effects of migration, climate change, tectonic activity and ecological shifts.

Revolution in human evolution (Gibbons):

New advances in DNA technology have forced a shotgun wedding between DNA specialists and researchers studying human origins and evolution. By studying DNA, researchers can learn about the ways our ancestors genetic legacy has shaped and informed our own genome. For example, an ancient variant present in Denisovans allowed them to use oxygen more efficiently than their contemporaries. This variant is now present in Tibetan populations and allow them to survive at high altitudes.

7. In the last few years there have been finds/analyses that raise questions about dividing early Homo into the two aforementioned taxa. Discuss one of these issues (for example, the suggestion made by the author of your text-Susan Anton--this is included on the handout.

Oldest finds from 2/8/2.75 mya that are only designated as "homo" without a species designation. Others still classify most if not all of these early homo finds under the genus Australopithecus. Two primary approaches to dividing homo habilis into h. Habilis and h. Rudolfensis: The larger and smaller forms mentioned above Not size, but facial shape: differences in anterior palate, mandible and facial shape. Taxonomic names not assigned. "1470 group": short and flat anterior dental arcade and relatively tall flat face versus the "1813 group": round and more projecting anterior dental arcade and a more primitive face

3. Who is Archicebus Achilles and how does he impact our understanding of early primate evolution?

Oldest known primate fossil (around 55 million years old). Suggests a pivotal event in human and primate evolution- the evolutionary lineage leading to modern human, apes, and monkeys. Very small and overturns idea that original basel primates were large.

An ancestor to call our own (Wong):

Orrorin tugenensis could fill the gap between Lucy and our divergence from chimpanzees. It has some homo traits, like a human like femur which could suggest bipedalism, but also a mix of primitive traits. Some scientists challenge claims of bipedalism and point out that the femur has other chimp-like traits and that the taxa may have been only partially bipedal in the way orange and chimps are. Another taxon, Sahelanthropus, another possible candidate for a human-ape common ancestor, was also found, though it had no postcranial bones, so we do not know if it was bipedal. It lacks the CP3 complex, showing a tendency towards human-like dentition, though it has strong ape like features, like a small brain case and widely spaced eye sockets, it could really be our last common ancestor with apes.

1. What are the epochs of the Cenozoic and what is the time frame for each?

Paleocene is 65-55 mya: K/T boundary means more angiosperms and insects, temperate with no seasons, time for plesiadapids Eocene is 55-34 mya; warmest epoch, NA and Europe start to break apart but there are still land bridges. Time of mammalian radiation, time for euprimates. Oligocene is 34-23 mya; cooling and drying period leads to the Great Cut, 90% of primates die, time for anthropoids. Miocene is 23-5.5 mya; cooling period in Africa during middle Miocene wipes out the proconsulids, as the forests shrink and there's an increase in savannahs and open woodlands, African and European plates reconnect, allowing for migration—radiation of apes. Late Miocene, refugia are all that remain, cercopithecoids radiate as apes die. Pliocene is 5.5-2.6mya; only refugia remain, gracile australopithecines Pleistocene is 2.6-10,000 BP; Vrba's turnover pulse leads to new, more open environments and harder foods, robust australopithecines emerge. Holocene is 10,000 BP-present PEOMPPH people eat over my pretty pink house

17. Do you think that the variation in H. erectus use (sensu lato) warrants a species level distinction? Why? Be specific. You can't be wrong but you have to defend your answer based on the morphology and understanding of how variability in a collection of fossils can be explained.

Personally, no I do not feel that the variation warrants a speciation event. While there are clear contrasts between Asian and African forms, in terms of the brow, occipital angle, sagittal keel and forehead slope, I believe this variation can be attributed to general variation as an adaptive response to varying ecological changes as they populated a large and varied area of the world during a time of varying climate from glacial advancements and recessions. I also think that the presence of OH9 in Africa with Asian traits and some fossils with seemingly trait from both suggest that the variation is not distinct enough to warrant speciation.

8. What is your perspective on the debate above the issue of variation in early Homo, how do you explain the variability in early Homo--one taxa, two, more than two? And if more than one, who will be ancestral to Homo erectus? Should we even keep the taxon H. habilis? Be specific in your reasoning.

Perspective 1: I view early Homo as one extremely diverse taxon (H. habilis sensu lato). The differences between the smaller and larger forms can be explained as general variation to adapt to differing climates. The Leakey's new find of a mandible to fit with 1470, displaced the mandible 1802 that had priorly been matched with it. Some say that because this jaw fits nowhere it could indicate another taxa, but because we have only the jaw and no others like it pathology cannot be ruled out to explain the variation. I do not feel that H. habilis should be killed off and considered an Au. because the forms show enough tendency towards Homo to be differentiated, such as significant brain reorganization, parabolic jaws, higher and rounder skulls with a loss of prognathism, and the evening out of teeth. Perspective 2: I feel that there are 2 taxons, H. habilis (sensu stricto) and H. rudolfensis. The variation between the "smaller" and "larger" forms (differing brain size, face shape, and dentition) is great enough to suggest the presence of two species. It is likely that H. erectus evolved from H. habilis rather than H. rudolfensis because habilis has thinner jaw with smaller, narrower molars and premolars and a less flat face that is broader across the upper face, which is more traditionally Homo. Rudolfensis, on the other hand, has a thick jaw with large, wide molars and has a broader flatter midface, reminiscent of australopithecine forms. The only non-consistent feature is the larger brain of H. rudolfensis, but this can be explained as the taxa possibly being larger in general and doesn't necessarily mean it had a relatively larger brain size. I do not feel that H. habilis should be killed off and considered an Au. because the forms show enough tendency towards Homo to be differentiated, such as significant brain reorganization, parabolic jaws, higher and rounder skulls with a loss of prognathism, and the evening out of teeth.

3. What traits do we see in the stem primates from this epoch that convince researchers that they are indeed true or euprimate?

Petrosal bulla, post-orbital bar, hands as an exploratory tool, opposable big toes and some thumbs, flexible bodies, nails, increase in brain convolutions, increase in vision decrease in smell, small and unspecialized incisors (unlike the rodent-like ones in plesiadapids) because hands are grabbing food, increase in teeth showing frugivory and folivory.

6. Today there are three primary hypotheses concerning the phylogenetic status of plesiadapids. Describe each including the data/morphology that supports that view. [Consider the additional data presented in class i.e., discoveries/analyses after the 2002 announcement of Carpolestes that you read about in the Sargis article. I refer to finding about the petrosal bulla and the recent news from May 2017 (article distributed in class.)] Which view do you hold and why?

Plesiadapis are not primates Had outward facing eyes Relied more on smell than common day primates They are primates but not true primates (euprimates), instead they belong in a distinct family Some mix of these characteristics They are true/euprimates Flexible ankles suggest arboreality Less spiky molars Petrosal bolla Maybe had grasping hands Grasping feet Nail on big toe

5. For the two isotopic/radiometric methods presented in detail in class, describe those methods being as specific as possible. That is, make sure that your explanation including data on the material, whether the method is direct or indirect, the time range, the half-life of the isotope (even though this is off-the-record), what is compared, etc.

Potassium-Argon dating: indirect, dates volcanic material. Time range is from 10,000 to 4.5 billion years. The half-life of potassium to argon is 1.3 billion years. The longer time passes, the more argon accumulates; you want a tuff sandwich with volcanic material on either side. Radiocarbon dating: direct, dates bones. Time range from a few hundred years ago to 40,000 BP. Half-life of C14 is 5,730 years give or take 40 years. Compares the amount of the stable c12 to the unstable c14, which degrades over time.

2. What are the two broad categories of dating methods? What is one problem with drawing these categories?

Relative dating methods and chronometric dating methods. One problem is that "calibrated relative methods" do actually pinpoint a specific date by comparing a relative technique to an absolute time scale (ie. Paleomagnetism).

4. Who is Saadinius hijanzensis and how does he affect our understanding of early primate evolution? (For example, why would we say that Propliopithecus was an early catarrhine but that Saadinius was a derived catarrhine?)

Saadanius hijazensis has a 2123 dental formula and was an advanced stem catarrhine (right before split between cercopithecoids/hominoids). Lived 29-28 mya. Possesses features of both apes and monkeys. Exists in liminal state btw. these two categories. Lacks advanced sinuses of apes and monkeys. Has bony ear tube that was not developed in Propliopithecoidea.

10. Several taxa have been found that predate Lucy. What are their names, where and when are they from and how do they impact our understanding of human evolution? (There were several articles on the syllabus about some of these taxa, you might want to draw on one of them as you consider your answer).

Sahelanthropus tchadensis, 7-6MYA Central Africa, 320-380cc Debated biped, with an anterior foramen magnum, w flat horizontal nuchal plane No diastema, no C/P3 Parabolic dental arcade Orrorin tugenensis 6 MYA, East Africa Dentally primitive, but we have a femur that suggests it might be biped based on femoral head and muscle attachment Ardipithecus ramidus 4.4-3.9MYA East Africa, 300 - 350cc Anterior position of foramen magnum Pelvis mosaic is broad and short, like more humanlike forms Opposable big toe but not as curved as chimps Flexible wrist, so not a knuckle walker They challenge our understanding of human evolution because their bipedalism is unknown, and whether this bipedalism exists millions of years before Lucy will warrant a hominin status, changing phylogenies.

3. What do the terms sensu lato and sensu stricto mean?

Sensu lato = in the broad sense = h. Habilis encompassing all h. Habilis forms Sensu stricto = in the strict sense = 2 or more taxa: h. Habilis and h. rudolfensis

13. What are the ways that we assess variation in a collection of fossils? (Though there are many approaches to this I ask that you used the list discussed in class). This was asked last week as well but it is relevant here as well.

Sexual Dimorphism (physical differences between males and females beyond genitals) Chronological age (differences in individuals based on how old or young they were) Pathology (illnesses that could cause variation, needs to be ruled out) Geographic Origins (variation from adaptations to different geographic settings) General Variation (the variation from no two individuals being exactly alike) Time frame/chronological time (the fossils coming from different periods) Presence of more than one species

6. What are the ways that we assess variation in a collection of fossils? (Though there are many approaches to this, I ask that you used the list discussed in class).

Sexual dimorphism (male v female) Age (younger v older) Pathology (sick/well) Geographic origins (ancestry) General variation—more than one species present? Timeframe (ex. Fossils from 1 mya next to fossils from 300,000 bp)

7. This was off the record so I would never ask about it but for those who recall the story, what can we learn from the "rise and fall" of Sivapithecus?

Sivapithecus, one of the surviving great apes of Eurasia, had strongly built jaws, dentition well suited to soft fruits, shortened snouts and presumably large brains. Additionally, adaptations to suspensory locomotion with powerful grasping capabilities. Some believed the Sivapithecus like the Dryopithecus navigated the forest canopy like living great apes do but some skeletal features of the Sivapithecus suggest more quadrupedal habits. I really dont know and it doesnt matter.

19. Discuss at least three other aspects of what we know about H. erectus use (sensu lato) life styles (e.g, subsistence and the "other" categories from class, e.g., use of fire, life history/development, ?grandmothering", ?care of the elderly?, hair loss, ?art?). [The optional newspaper article packet explores these issues as does your text.]

Subsistence: We know from their tool use that H. erectus relied mostly on scavenging and small game hunting. It has been suggested that they may have also hunted big game through persistence hunting, keeping a larger animal running to exhaustion. This is possible because erectus was built to run, but we don't have enough evidence to know for sure. It is also possible that they were territorial scavengers, meaning that they managed their resources within their territory, though we don't know for sure. We do know that meat became an increasingly important part of their diet, as it was crucial to feeding their growing brain and body. Fire: there is eveidence that H. erectus exibited intentional use of fire. There are various possible advantages to this, such as cooking meat or other foods to make it more digestible, keeping warm, providing light, keeping away predators, etc. Loss of Body Hair: At about 1.8 MYA we see a divergence of 3 different types of lice, head lice, body lice, and genital lice. This suggests that erectus lost enough body hair to differentiate between hair in those three areas.

5. For the last twenty or so years, some researchers have drawn a distinction between Homo habilis (sensu stricto) and Homo rudolfensis. On what basis do they make this distinction (be specific in terms of morphological contrasts) that researchers traditionally have made between the "large" and "small" forms?

The "larger" would be h. Rudolfensis. The "smaller" is h. Habilis (sensu stricto). LARGER: BRAIN: 600-800 ccs, avg 750 cc FACE: More australopithecine-like, broader and flatter TEETH: larger molars, thicker jaws SMALLER: BRAIN: 500-670 ccs, avg 610 FACE: More homo-like (broad but not as flat) TEETH: smaller molars, thinner jaw

3. Name the other two candidates for earliest hominoid. Why do some researchers think that they are better candidates?

The Afropithecus and Morotopithecus are other candidates for the earliest hominoid. The proconsul is very primitive in some respects especially in regard to the backbone, pelvis and forelimbs which are more monkey-like characteristics -- suggesting the proconsol would have been better suited to travelling along the tops of trees. The Morotopithecus is thought to have been more suspensory but the evidence is inconclusive. The Afropithecus which migrated to Eurasia by land-bridge when global sea levels had a thick covering of enamel [good for processing hard foods and exploit food resources not available to the proconsol] -- this dental innovation may have played a key role in helping their descendant establish a foothold in Eurasia at a time when most of the early Miocene apes were going extinct.

16. Discuss one other new find that either helps to clarify the situation or adds more confusion to the issue of variation in H. erectus (sensu lato). [You can refer to the finds as the experts do, by their names or their numbers, e.g., Bouri, Illeret, Olorgesallie, SM3, Dmanisi]

The Dmanisi finds, of 5 skulls all in the same cave, further confuse the variation among H. erectus. Dmanisi 5 for example ha the basic erectus plan but is much shorter and has a tiny brain. They show great variability amongst themselves and look as if they could even be intermediate forms between erectus and habilis (Dmanisi 5 even shows australopithecine traits). Could mean additional taxa, could mean that H. habilis and erectus are the same species, could mean that there was just lots of developmental plasticity to cope with environmental stresses.

6. Why do researchers agree that the Middle Miocene forms from Africa and Eurasia are definitive hominoids? Be specific in terms of morphological features.

The Dryopithecus and other Middle Miocene forms are considered definitive hominins for these reasons: Evidence of knuckle-walking (SL) Fruit-eating (dentition) Tool use (powerful grasping capabilities) Evidence of Hunting (SL - especially in elbow joint which was fully extendable and stable throughout a full range of motion (Dryopithecus)) Living in highly complex social groups Forest-living (powerful grasping capabilities)

Sunset on the Savanna (Shreeve):

The Savannah Hypothesis for bipedalism has been popular since Darwin, but hard data linking the environment to human evolution was missing —> maybe drying up of African environments triggered "turnover pulse" —> that was proven untrue by soil testing. In 1995 Leakey discovered Anamensis, the habitat of which remains uncertain but could make or break the savannah hypothesis. (It's still debated.) Ramidus (which aligns with Afarensis) definitely lived in a wooded area. If it turns out to be bipedal, then that's it for the savannah hypothesis!

1. What features help us to distinguish hominoids from other anthropoids? Why is there difficulty in talking about shared derived traits for this group?

The features that distinguish hominoids from other anthropoids include: Cranials - increase complexity of brain; relatively larger brain; broader nose and palate; hominoids retain simple molars - 5 cusps (Cercopithicoids have bilophodant molars with 4 cusps: ridge between each pair... great for slicing and dicing leaves and hard foods) Post Cranials - No more tail; scapula moving towards the back facilitating 360 rotation; longer arms than legs; less flexible lumbar region for stability (stiffening vertical column); mobile wrists; broader and more shallow ribs xx

Alas, poor Notharctus (Alexander):

The first complete skull of a Notharctus lemur is found in Wyoming (small/broad face, fully binocular). A puncture behind eye reveals he was murdered by Vulpavus, an arboreal predator. Notharctus was a leaper with long, clinging hands and a long tail. It demonstrates the advancement of primate evolution even 50 mya during the Eocene.

15. What are some of the problems in drawing a clear distinction between "Asian" and "African" finds? For example, why is the skull labeled OH9 -analyzed by the class—such a problem for a neat geographic split?

The problem encountered is that odd finds have been found in both Asia and Africa that blur the distinction between the two. OH9, for example, is an Asian looking form with an angled braincase, thick (but curved) brows, and a sloping forehead, but it was found in Africa. This is especially problematic for people that want to divide Asian and African forms into two taxons, H. erectus (sensu stricto, Asian forms) and H. ergaster (African).The presence of OH9 makes dividing H. erectus much harder because the geographical distinctions between them are less clear.

Mystery Human (Wong):

This article chronicles Berger's discovery of hominin fossils in an underground cave. This discovery garnered much controversy, as his rush to publish his findings and unearth all the fossils led many to believe his dating was messy and unearthing the fossils severely damaged them. However, the placement of the fossils raises many questions about whether intermediaries buried their dead/cashed them into this cave, or whether the placement of these bodies was a mere accident.

Stalking the giant ape (James):

This article covers Olsen and Ciochon's quest to find fossils of Gigantopithecus (also known as Giganto) in Vietnam. Evidence suggests that the giant ape may have lived at the same time as and interacted with homo erectus and the scientists want to know if man could have been partially or fully responsible for their extinction. Though most Giganto fossils are found in China (all teeth, mainly large molars) the chinese practice of using crushed fossils medicinally pushed them to look in Vietnam, where recent finds had shown Giganto and man to be present together. They were brought to Lang Trang, a fossil rich cave which has so far not healed a Giganto fossil but has shown promising evidence that some may be present.

Ape at the brink (Savage-Rumbaugh, S and R. Lewin):

This article follows a team of scientists as they try to get a chimp to recreate tools made by hominins. In part, the scientists want to know whether early tool use and creation was beyond the cognitive capabilities of apes, or apes simply did not make tools. Although Kanzi learns the necessary technique to make Oldowan tools, analysis showed that he did not measure up to the same consistency and efficiency as the tools made by the original makers of Oldowan tools.

Burning Man (Wrangham):

This article suggests that humans evolved as a result of H. erectus cooking its food. We, the modern Homo sapien, have small teeth, small guts, weak jaws, and lower tolerance to toxins and tannins than most mammals. Cooked food is softer, easier to digest, gives more energy so less needs to be spent on digestion, and helps make food high in toxins digestible. These traits then could have evolved in response to our ancestors cooking food. Additionally we see H. Erectus, around the time it lost its climbing adaptations, started to sleep on the ground which is rare for primates. The presence of fire could explain this, as it would keep predators at bay.

2. What traits suggest to some that Proconsul is the earliest hominoid? What features raise questions about this for some so that they think he is a derived catarrhine?

Traits that suggest the Proconsul is the earliest hominoid: Cranial -- larger, rounded braincase; small incisors; short, vertical face; neck area faces back and down; orbits fully front-facing. Post-cranial -- its limb and body proportions as well as its adaptation for climbing enable us to assume the proconsul was a quadrupedal, arboreal monkey-like form. The more monkey-like characteristics such as the backbone, pelvis and forelimbs of the proconsol suggest it was better suited to travelling along the tops of trees leading some to believe the proconsolids are ancestors to chimpanzees and actually are derived catarrhines. Essentially th proconsol had not yet adapted limb mobility or brain size associated with modern apes.

1. What was the ecological and geological context for the Eocene and how might this have affected primate evolution during this epoch?

Warmest geological era,tropical rainforests good for arboreality and frugivory. Land bridge between Eurasia & America allows for primates to spread outacross land mass

12. Two new species of Australopithecus have been announced in the past year. Who are they, were and when are they from and why are they important?

We don't know the answer 4 this **know one for the exam. Know name, date, location, and nutshell fact. Australopithecus prometheus. 3.5-3.3 mya. East Africa. Small foot but big ankle—puts the attention on South Africa. 3.67 mya. East Africa (Ethiopia) strong jaw, bipedal. Both are contenders for Lucy (Australopithecus afarensis), upright walking early hominin.

10. Given what you know of tool making in other animals, primate and non-primate (e.g., birds such as the one in the video posted to the class wiki-in the news) to what extent to you view this as a distinguishing aspects of humans? Are there aspects of human tool making that in your view make it different?

We know that toolmaking is not unique to the genus Homo as once believed. It was once also thought that it was the use of stone tools that differentiated us, but the finding of Lomekwian tools dated 3.3 MYA dampens this and suggests someone much older used stone tools as well (chimps have also been filmed manufacturing and using them). Ultimately, what differentiates tool use in Homo is the extent of its impact on lifestyle. Tools in other animals, primate and non-primate, are useful, but don't trigger a big lifestyle change as seen in Homo.

1. What are the current options in terms of where and when the earliest anthropoids emerged? Can you name one of the candidates?

Where: Africa or Asia When: 40 mya, 45 mya, 50, or 55 Achilles-name of oldest primate fossil (lived 7 mya)

6. How do Au./P. robustus and Au./P. boisei differ from each other?

Whereas Au. robustus can be called a "chewer", boisei can be called a "super-chewer" --- boisei is hyper-robust Boisei has, relative to robustus, -Less prognathism -A dish-shaped midface -A saggital, or nearing completely flat, face -Post-orbital constriction -Much larger P and M, with tiny tiny canines and incisors -Has a huge, thick jaw with thicker enamel -Highly sexual dimorphic -Prominent sagittal and nuchal crests, but not compound as in afarensis -Strong facial buttressing, with boisei having a more "saddled" face Jaw and cranium make a more perfect right angle in boisei, where robustus is a little more oblongly angled

New women of the ice age (Pringle):

"Black Venus" figurine found in a village in the Czech Republic. At 26,000 years old, it ranks as one of the oldest depictions of women and may reflect the sexual politics of the Ice Age. Originally thought to serve as a male-made depiction the feminine in a society where women were pampered while men hunted big game with spears. However, recent evidence suggests that women were involved in food gathering and techniques of hunting using woven nets, a communal practice involving the labor of children and women. Moreover, the conception of Ice Age men as big game hunters is also most likely false, instead they were probably scavengers who picked berries and picked the meat off of decaying bones.These Venuses weren't made for pornographic purposes, but rather played a key role in shamanic divination rituals centered around women.

2. What does the term "stem" mean when we refer to stem primates or stem anthropoids?

"Stem primates" indicate primates that haven't yet evolved into strepsirrhines or haplorhines. They are primates that haven't yet developed the morphological features to be categorized as such (same goes with stem anthropoids). The split of stem primates into strepsirrhines and haplorhines happened about 58 mya. Stem primates split btw. 58-48 mya.