Anth 309 Post middy lec + lab content

What notable shifts in features do we see between australopiths and homo?

• Increased brain size

• Increased body size (mass, height)

• Change in body proportions (long legs, shorter arms)

• Decreased sexual dimorphism

List the species in the grade “Habilines”, include dates and location

Homo sp. 2.8Ma Eastern Africa

Homo habilis 2.4-1.4Ma Eastern and South Africa

Homo rudolfensis 2.0-1.8Ma Eastern Africa

Homo sp. (Ledi Geraru Manidble)

Likely a new species, more primitive than H.habilis

Mandible from Hadar, Ethiopia

2.8Ma

Derived Features: small molas/premolars, corpus shape

Primitive: sloping mandibular symphysis

+ KNM-ER 5431 set of teeth from Koobi Fora could be same taxon

Homo habilis

Where: Olduvai Gorge, Tanzania Turkana Basin, Kenya Omo and Hadar, Ethiopia Sterkfontein and Swartkrans, South Africa

Age: 2.4-1.4Ma

• Oldest material from east Africa (2.4Ma), South Africa younger (2.0Ma)

Type: OH7 Juvenile Partial Skeleton

Key Features: Brains size >600cc, tool making, primitive limb proportions, obligate biped, precision grip

Homo habilis cranial features

• Brain size 600cc (larger than apes/australopiths)

• Widely spaced temporal lines

• Supraorbital sulcus

• Double arched, small supraorbital torus

• Small dentition

• Rounder cranium

• reduced prognathism

Homo rudolfensis cranial features

• Brain size 752cc

• No supraorbital sulcus

• small supraorbital torus

• Large flat face - wide maxilla

• Larger anterior dentition

What are the apomorphies of H.erectus?

• Sagittal keel

• Occipital torus

• Long skull (football shape)

Homo erectus cranial features

• Brain size 1000cc

• Sagittal keel

• Large, shelf-like supraorbital torus

• Occipital torus

• Almost orthognathic

• Long skull, football shape

• Rounder/domed skull

• Smaller dentition (than H.habilis)

Home rudolfensis

Where: Turkana Basin, Kenya Omo, Ethiopia

Age: 2.0-1.8Ma

Type: no typ designated, lectotype: KNM ER 1470 skull

Key features:

• Brain size 752cc

• Large, flat face

• Larger molars than H.habilis

What material/info confirms that H.habilis and H.rudolfensis are different species?

A mandible (KNM-ER 6000) and face (KNM-ER 6200) attributed to H.rudolfensis show:

• Larger anterior dentition than H.habilis

• Large, flat face, not H.habilis-like

What was the historical view of what makes a species “Homo” and what has discredited this?

The 1960s view:

• Larger brain size

• Language

• Tool use

• Precision grip

We now know that australopiths had tool use and precision grip, blurring the lines between these two genus

What primitive features do we see in Habilines? Derived features?

Primitive:

• Small body size

• Australopith body proportions

• Teeth larger than later Homo

Derived:

• Larger cranial capacity (still smaller than later Homo)

• somewhat reduced dentition

• more developed precision grip

• rounder cranium shape

Homo erectus

Where: Africa, China, Indonesia, Georgia. Very wide dispersion (oldest fossils in Africa)

Key sites: Turkana basin, Kenya. Dmanisi, Georgia

Age: 1.9-0.4Ma

Type: Dubois’ skull cap (Trinil, Java)

Key features:

• Brain size +1000cc

• Molars similar size to modern humans (slightly larger)

• Acheulean Industry tools

• Postcrania similar to modern humans

Homo erectus postcrania

• Long legs and short arms

• Narrow pelvis

• Large leg joints

• Long femoral neck

(Very modern human-like)

What are the 2 hypothesis about H.erectus? What is the support for each?

H1: 1 variable species; Homo erectus

• Quantitative analysis (measurements): shows continuous variation and cannot separate asia and africa specimens

H2: 2 species; Homo ergaster (early african) and Homo erectus (asia)

• Qualitative analysis (presence/absence of traits): Suggests that the variation is geographically distributed and there is too much variation for this to be a single species

Explain the first out of africa event, why did it occur?

Homo erectus appears to be the first to disperse out of Africa

• Left by 1.8-2.1Ma

• Very quickly spread across Asia

Why? Many possible reasons or a combination of them:

• Following prey

• Change of climate in Africa: middle pleistocene had lots of changes in climates

• population growth

• competition with other animals or hominin species

Explain the findings at the Dmanisi site

Site: ~1.8Ma

5 crania and 5 sets of postcrania + oldowan tools

• Lots of variation (including high sexual dimorphism)

• Small brain and body size (below 800cc)

• cranially oriented glenoid (like lucy, climbing feature)

Derived:

• Cranium shape

• limb proportions

Gibbons 2013 paper

What dietary shift do we see with the appearance of H.erectus? What evidence supports this?

Increase in brain size and body size in H.erectus suggests an increase in available energy, main suggestion for where this energy came from is a major increase in meat consumption

Evidence:

• Hominin anatomy

• New tools (Acheulean tools, often found with animal bones)

• Animal bones (increase in sites with stone tools present too, extensive processing)

• Changes in African communities (larger herds, carnivore decline)

• Tapeworms from raw meat consumption

Explain the Expensive Tissue Hypothesis and its relation to early Homo diet

Bigger brains and bigger bodies evolve ~2Ma in H.erectus which requires great energy to maintain

The expensive tissue hypothesis suggests that energy budgets are fixed and therefore tradeoffs occur between expensive tissues (in this case brain and gut)

H.erectus able to have a shorter,smaller gut because they consume meat (higher energy with less consumption needed)

When do we see first evidence of fire use?

Solid evidence that hominins used fire by at least 1Ma

• Soil chemistry changes that match campfires: high heat for prolonged periods produces oxidized soils

• Bones and plant remains that show changes consistant with >400°C

Controversial sites from 1.5-1Ma

What makes hominin carnivory unique amongst primates?

1. Use/manufacturing of stone tools

2. Acquisition of resources from animals larger than themselves

3. Complex mix of hunting strategies + scavenging

How does Hominin anatomy (H.erectus) support the theory of an uptick in meat eating?

Dentition: reduced teeth size, jaw size and muscle size

Larger bodies: easier to hunt large prey

Longer legs: can travel further for prey

Thorax shape: cone-shaped thorax no longer present in H.erectus, suggests smaller guts

Explain hypervitaminosis A and how this is evidence of H.erectus meat-consumption

Hypervitaminosis A is a condition that can be acquired by eating the liver of carnivores and can be evident on the bones

A 1.7Ma erectus skeleton from Koobi Fora displays this condition

Explain how tapeworms provide evidence of H.erectus meat-consumption

Tapeworms are gotten from consuming raw or undercooked meat

• All human-specific tapeworm species are closely related and giverged 780,000-1.7Ma

• +Our tapeworms are most closely related to those that live in African Carnivores

• Suggests that meat-eating was occuring with enough frequency that tapeworms adapted specifically to hominin hosts around this time

What is the alternate hypothesis to increased meat-consumption in H.erectus?

Suggests that the major change was cooking of plant foods, specifically of underground storage organs (tubers). This would reduce the energy needed to process these foods and make them more easily digestible and the energy more available

However there is lots of evidence that stone tools were being used to process meat specifically. Plus there is no compelling evidence of fire use 2ma

Homo aff. erectus

Homo affinity erectus as in similar to erectus but is something different

Where: Sima del Elefante, Atapuerca, Spain

Age: ~1.2Ma

Type specimen: none

Key material: facial fragment and mandible, tools, processed animal bones

Key features: First European hominin

• narrow face and distinct nasal region compared to erectus

• taller midface than H.antecessor

Homo antecessor

Where: Gran dolina, Atapuerca, Spain

Age: 900,000 - 800,000

Type specimen: ATD 6-5 mandible

Key material: 11 individuals to date - all but 1 juveniles/infants

Key features:

• Clear evidence of cannibalism

• Posses canine fossa

• short midface (more modern)

• infraorbital plate (under eye) sloped posteriorly

Explain the network of caves in Atapuerca, Spain. What has been found in each cave?

A network of caves varying in age

Cave 1: Sima del Elefante

• Age ~1.2Ma

• facial fragment and mandible of Homo aff. erectus

• tools and processed animal bones

Cave 2: Gran Dolina

• Homo antecessor- 11 individuals (all but 1 juveniles/infants)

• cannibalism evidence

• stone tools and animals bones

Cave 3: Sima de los Huesos

• Age: ~400,000

• >5,000 bones (MNI=28) most agree to assign this material to H.heidelbergensis

• However share some features with Neanderthals (possibly ancestors to or early version of): midface projection, taurodont molars

• Provides evidence that H.heidelbergensis may be the ancestor of neanderthals

• Most died in their prime (18yrs old)

• Unknown how so many bounds ended up in this pit but was not accidental

Homo heidelbergensis

Where: Europe, Asia, Africa

Age: ~800,00 - 200,000

Type specimen: Mauer mandible (from Germany)

Key features:

• brain size ~1200cc

• Human-like postcrania

• Culture: Levallois tradition, hunting, fure, range expansion

Homo heidelbergensis technology and culture

Strong evidence for active hunting of big game:

• Butchered horses, rhinos etc.

• possible game drives

• Schonigen spears (wooden tools)

• Aucheulean industry tools + levallois technique: major innovations in flake preparation

Fire/cooking

Homo naledi

Where: Rising star cave system, South Africa

Age: 236,000-350,000 (controversial)

Type specimen: DN1 male cranium

Key features:

• small brained 456-610cc

• Habiline-like (compatible w/ ~2ma): similar to H.habilis or A.sediba

• Curved phalanges, cranially oriented glenoid, short stature

• BUT: modern limb proportions, smaller supraorbital torus, modern hands

Dr.cote puts this species in with the Habiline grade

Explain the rising star cave system, what was found in each cave?

A cave system in South Africa contained H.naledi specimens, 3 main areas:

Dinaledi:

• At least 15 individuals

• Dated but shows clear disturbance (+hard to access)

Lesedi:

• At least 3 individuals

• not dated

UW110:

• Found recently

• contains “Leti” - juvenile

Homo neanderthalensis

Where: Europe, Middle East, Central Asia

Age: 150,000 - 30,000

Type specimen: Feldhofer 1 - skull cap and partial skeleton

Key features:

• Brain size 1450cc

• Cold-adapted, robust postcrania

• Culture: Mousterian tradition, hunting, fire

Homo neanderthalensis cranial features

• Brain size 1450cc

• small, sloped forehead

• supraorbital sulcus + torus

• Tall midface with large nasal openings

• long, round skull

Apomorphies:

• Occipital bun

• Retromolar space

• midface projection

• Taurodont molars

Classic features (seen in other hominins, separates them from homo sapiens)

• no chin

• mental foramen below M1 (below p4 in sapiens)

• Absence of canine fossa

Homo neanderthalensis postcranial features

Short and stocky with large muscle attachment areas. Compared to Homo sapiens:

• Hyoid bone like modern humans

• Larger, wider thorax (larger lung size)

• shorter radius & ulna

• Wider pelvic inlet

• Larger, strongly muscled hands

• Ant-post bowed femur

• tibia shorter relative to femur

What is the origin of Neanderthals?

• Likely evolved from European branch of H.heidelbergensis

• Evident from Sima de los Huesas hominins which show some neanderthal traits

• “Classic” Neanderthal features don’t appear until later

What does Neanderthal tooth ware say about their behaviour?

• Large, worn anterior teeth suggest paramasticatory activity: pulled meat or hide through their teeth

Describe the life history of neanderthals

Neanderthals grow differently/faster than humans

• Teeth form quicker

• M3 erupted at age 14 (18 to humans)

• Rapid cranial growth early + late growth spurt in brain, especially occiptial lobe (hence occipital bun)

Neanderthal birth likely difficult but not the same as humans

• somewhat wider pelvis

• Do not experience the twist if fetus moving from pelvic inlet to outlet that humans do

Age of death 40-45yrs

• many older individuals

• many healed injuries

• suggests altruistic care

Describe the cold adaptions of Neanderthals, why would they need this?

During the upper pleistocene (when neanderthals existed) there was an ice age from 120-12Ka which means much of the Neanderthals range in time and space was associated with cold climates

• Large projecting nose: increase surface area to warm and humidify air

• short and stocky- allens rule

Describe the technology used by Neanderthals

Mode III tools:

• 300,000 - 35,000

• fewer bifacial cutting tools

• appearance of Levallois technique

Mousterian industry (a specific predominant industry within mode III):

• appears later with Neanderthals and includes Levallois-prepared tools

Evidence of complex tools

• Hafting points onto spears

What evidence is there for meat-eating in Neanderthals

Climate

• Human arctic foragers used as models (but they consume aquatic mammals so not exactly alike)

Nitrogen isotopes

• Neanderthals consuming more protein than cave bears from same archaeological sites

Animal bones

• Majority of animal bones found in and around neanderthal sites are from large prey

Coprolites

• Fossilized faeces contain meat

What evidence is there for plant-eating in Neanderthals

Dental calculus

• scraped from teeth of 3 neanderthals

• microfossils of plant starches and phytoliths preserved in the calculus

• barley starch grains show damage similar to having been cooked

Coprolites

• Fossilized faeces contain some plant material

Is there evidence of cannibalism in Neanderthals?

Yes it was relatively common behaviour, 25% of Neanderthal sites have some evidence of cannibalism

• Abri Moula best evidence: pattern of cut marks and bone breakage of neanderthal bones matches the butchery marks on deer of same site

What evidence of cilture/symbolic behaviour do we see in Neanderthals

Art/Symbolism

• cut marks on bones in simple patterns unrelated to butchering

• shells and talens perforated- looks like wearing as some sort of adornment

• controversial but some cave paintings have been re-dated prior to Homo sapiens arrival in area

• Jaubert et al.

  • Stalagmite accumulations/arrangements

Burial of dead

• carefully done with characteristic positions

• possible grave goods: animal bones, flowers, shells

What factors possibly played a role in Neanderthals becoming extinct?

1. Climate change: warming, megafaunal extinction

2. Homo sapiens: competition, disease introduction.

3. Demographics: small populations, inbreeding depression, reproduce slowly

What is aDNA? What challenges does this method have?

aDNA: ancient DNA recovered from fossils

Challenges:

• DNA can be destroyed by time, temp., oxygen, and water

• Nuclear DNA degrades faster than mtDNA, so often mtDNA is what is the aDNA available

• aDNA can be very easily contaminated by modern DNA

• Very time consuming and expensive to ‘amplify’ the tiny amounts of DNA extracted

How does aDNA tell us Neanderthals, Modern Humans and Denisovans related?

Neanderthal DNA demonstrates that Neanderthals are not part of Homo sapiens (genetically distinct) but there has been admixture (hybridization)

• aDNA indicates that LCA of Neanderthals and Modern humans >650,000

Denisovans are more closely related to Neanderthals than Homo sapiens but interbred with both

• aDNA indicates LCA of Neanderthals and Denisovans >400,000

What hominin species do we have aDNA from?

• Neanderthals

• Denisovans

• Modern humans

How old of a specimen can we likely get aDNA from? What is the half life of DNA?

currently thought that sequences older than ~1.5Ma will not be properly readable even with good preservation because DNA has a half life of 521yrs (meaning half the bonds between nucleotides are destroyed after 521yrs) so after a certain point so many of the bonds are broken that it is not possible to piece together

What is the oldest aDNA to date? What about oldest from a hominin species?

From frosen conditions we have siberian mammoths (>1Ma), a horse from a leg bone (560,000-780,000) and envrionmental DNA (2Ma) that is readable to the family level

Oldest hominin aDNA: Sima de los Huesos (that Neanderthal ‘pit of bones”)

• ~400,000 yrs old

• Femur and incisor have produce aDNA

Denisovans

Where: Denisova Cave, Siberia, Russia

Age: ~40,000 - 160,000

Type: none designated (species hasnt been named)

Key features: Large molars (for age/time period, larger than modern humans and neanderthals)

Material: 1 finger bone, 3 molars, skull fragment (from older layers, could be 285,000yrs old)

Explain the Denisova cave and what aDNA has told us about the specimens here

Denisova cave in Siberia, Russia contains a long archaeological sequence of bones and artifacts. It was known from archaeology that both Neanderthals and modern humans had occupied this cave over time but aDNA of the hominin bones allowed us to identify the Denisovans.

aDNA of the bones in this cave also allowed identification of interbreeding between the 3 species and their phylogenetic relationship

Denisovans vs Homo longi

A cranium in Harbin,China was published as a new species Homo longi but through preoteomics and the discovery of Denisovan eDNA at the site it is likely that this is actually Denisovans from China

• +similar molar size and morphology

• Many similarities to Neanderthals (like Denisovans)

What species are still present during the Late Pleistocene and where?

• Homo neanderthalensis (Europe)

• Homo longi/Denisovans (China)

• Homo Erectus (China)

• Homo floresiensis (Flores, Indonesia)

• Homo sapiens (Africa → disperse)

Describe the model for the origin of modern humans: Multiregional model

Argues for a singular Out of Africa event, H.erectus. So has all been 1 species since about 2ma and evolves into modern humans:

Suggests that the spreading of Homo erectus out of Africa led to populations in Europe, Asia and Africa, interbreeding between these populations maintain them as a singular species (continuous gene flow between regions)

Describe the model for the origin of modern humans: Out of Africa model

Suggests 2 Out of Africa events and Homo sapiens evolving completely independently within Africa before dispersing and replacing other hominins in Europe and Asia:

Suggests that Homo erectus spreads out of Africa and other hominin species (ex. Neanderthals) persist in Europe, Asia and Africa. Then Homo sapiens evolve in Africa and disperse out of Africa replacing the other hominin species in each area

Describe the model for the origin of modern humans: Admixture model

The middle ground model: Argues that Homo sapiens mark a second out of Africa event but as they dispersed they interbred with other hominin species (rather than just replacing them)

Suggests that Homo sapiens evolve independently in Africa and disperse out of Africa after H.erectus. As the disperse some interbreeding with other hominin species occurs

What predictions come with the Admixture model for the origin of modern humans? Does evidence support these predictions?

P1: Small genetic differences between groups, most variation is within groups

• Based on genetic/DNA data we can see a serial founder effect: genetic diversity decreases with distance from Africa

• This aligns with the model because the groups that migrated out of Africa would be quite small and as would each migration beyond that (founder effect occurs in each new place) + farther areas from Africa would have been founded more recently so less time for genetic diversity development

P2: Shallow genetic roots because all humans are derived from a recent speciation event

• both mtDNA and nDNA shows the greatest variation in African populations and that the LCA of all humans today was ~200,000 - 300,000 yrs ago

P3: Modern humans appear in Africa first

• oldest Homo sapien specimens found in Jebel Irhoud, Morocco (North Africa), dated to 300,000 (some consider these late H.heidelbergensis)

• Oldest widely accepted Homo sapiens fossils are from Ethiopia (Omo Kibish skulls 200,000+)

P4: Evidence of interbreeding with other hominin species

• Homo sapiens moved into the Eastern Mediterranean and lived in this region with Neanderthals for 60,000yrs, this aligns with when genetics tells us the first admixture event occurred

• See evidence of interbreeding with Neanderthals and Denisovans in genomes of modern humans

P5: Modern human archaeology appears in Africa first

• Evidence of blade technology, bone tools, long distance trade and use of pigments/decoration in Africa during Middle Stone Age

Describe the 2 models for the development of behavioural modernity

Cognitive leap at ~50,000

• Richard Klein suggests there was a “creative explosion” - modern human behaviours arose suddenly and simultaneously throughout the Old World about 40,000 - 50,000yrs ago

• is based on archaeological evidence of Europe that shows advanced tools, art etc. around this time

Gradual increase throughout modern human history (the correct theory)

• Africa evidence shows that the archaeological evidence found in Western Europe dated to the Upper Paleolithic era (40,000 -50,000) are evident in Africa during the Middle Stone Age (different naming method for time periods in African research, this era is earlier than the upper paleolithic)

• This suggests that lots of this technology, cognitive abilities and culture existed before Homo sapiens left Africa and their behaviour/technology gradually developed as they dispersed/time progressed

Homo sapiens

Where: Africa first, the everywhere

Age: Molecular clock says earlier, fossils 200,000+

Type specimen: Carl Linnaeus

Key features:

• Brain size 1350cc average

• chin

• forehead

• small face

• culture: art, symbolism, language

• slow maturation and extended juvenile period

What are the theories on why chins evolved in Homo

1. Helps a thin mandible to resist bending forces from chewing/talking

2. Sexual sexual for chins

3. Not an adaption, a by-product of something else (aka a spandrel)

H3 is the leading hypothesis

Homo floresiensis

Where: Island of Flores, Indonesia

Age: ~100,000–60,000 (bones), 190,000–50,000 (stone tools)

Type specimen: LB1 skull and partial skeleton

Material: At least 9 individuals in the Ling Bua cave, stone tools, evidence of fire use

Key features:

• Short stature (3.5’ tall)

• Small brain ~400cc (chimp. sized)

• Postcrania is a mix of early Homo and Australopithecus features

• Culture: Tools similar to H.erectus in Asia, big game hunting, fire use

When and how did Hominins arrive in Flores

The island of Flores in Indonesia has been isolated for a long time so to get to the island either they would have had to use “boats” or sweepstake dispersal occurred - transported there during a storm/weather event

Evidence (stone tools) suggests that hominins arrived on the island ~1Ma

What are the 3 hypothesis of what H.floriesensis are? What evidence supports/discredits each?

H1: These are just small Homo sapiens and LB1 (type) is microcephalic

• Discredits:

  • - Reconstruction of LB1 brain compared with many humans shows that not similar in shape to H.sapiens

  • - Discovery of more specimens shows they are of similar stature and brain size to LB1

H2: Descendants from a population of Homo erectus that evolved reduced body size

• Supports:

  • Reconstruction of LB1 brain is most similar in shape to H.erectus reconstructions

  • Insular dwarfism is a common occruance when large mammals are isolated on islands

• Discredits:

  • Brain size-body size ratio more like australopiths and in insular dwarfism brain size usually reduces at the same rate as body size

  • postcrania not similar to H.erectus

H3: Descendants from an earlier unknown immigrant hominin species from mainland Asia

• Supports:

  • Postcranial features similar to Australopith or H.habilis, but with longer feet

  • Evidence of hominin activity on the island much earlier than H.floriesensis:

    • Mata Menge, Flores is a 700,000yr old site that contains mandible, cranial fragment and teeth of individuals that were all smaller than LB1

    • + site has tools similar to H.floresiensis (behavioural stability?)

Homo luzonensis (+validity of species)

Min. 3 individuals found in Callao Cave, Phillipines dated to 50,000-67,000

Poorly known: Dwarf species, teeth smaller than H.floresiensis, curved phalanges

Argued that there is not enough comparison to H.floresiensis to prove they are different species

Label the skeleton

A- skull

B- mandible

C- clavicle

D- scapula

E- thorax

F- ribs

G- humerus

H- radius

I- ulna

J- pelvis

K- sacrum

L- coccyx

M- carpals

N- metacarpals

O- phalanges

P- femur

Q- patella

R- tibia

S- fibula

T- calcaneus

U- tarsals

V- metatarsals

W- phalanges

Label the skull

A- frontal

B- parietal

C- temporal

D- occipital

E- zygomatic

F- mandible

G- maxilla

H- nasal

What differences do we see between human and chimpanzee skulls?

Foramen magnum location

• Inferior and more anterior on human

• more posterior on chimp

Temporal lines

• Less prominent, widely spaced in humans

• Prominent and close together in chimps

Supraorbital torus

• Reduced, not prominent in humans

• Large, prominent in chimps

Prognathism

• Flat face in humans

• Strong prognathism in chimps

Nuchal line position

• more inferior, smaller in humans

• more superior, larger in chimps

Post orbital constriction

• not present in humans

• present in chimps

Dental formula for chimps? Humans?

The dental formula for both chimps and humans is 2123

What features of the Toumai skull of Sahelanthropus tchadensis cause disagreement about the sex of the specimen?

Large supraorbital torus suggests male

Small canines suggest female

Explain the basics of writing tooth positions

When you write out a tooth, you would use lower case or subscript for teeth of the lower jaw, and upper case or superscript for teeth of the upper jaw, as follows:
Upper jaw (Maxilla): I1, I2, C, P3, P4, M1, M2, and M3 OR I¹ , I² , C^x , P³ , P⁴ , M¹ , M² , and M³
Lower jaw (Mandible): i1, i2, c, p3, p4, m1, m2, and m3 OR I₁ , I₂ , C_x , P₃ , P₄ , M₁ , M₂ , and M₃3

What is a key postcranial feature of ardipithecus ramidus that differentiates this species from others?

Opposable hallux (big toe)

What do the features of ardipithecus ramidus suggest about the species’ locomotion? What feature that is no preserved would be helpful in better understanding their locomotion

• Opposable hallux suggests not a committed biped

• Phalange length and curvature suggest strong muscle attachment, useful for climbing

Calcaneus (a foot bone) is not preserved, this would be useful to see if they had an arch, a feature that helps with bipedalism

How does the pelvis of Australopithecus afarensis (lucy) compare to chimps and humans?

Lucy’s pelvis is much more similar to humans than chimps:

• Wide, short sacrum in lucy/humans, narrow and long in chimps

• Short illiac blade in lucy/humans, tall in chimps

• Deep sciatic notch in lucy/humans, shallow in chimps

• Anterior/inferior illiac spine present in lucy/humans, absent in chimps

• large area for hip abductors in lucy/humans, small in chimps

How do the cranial features of Australopithecus afarnesis compare to chimps and humans?

Prognathism

• Intermediate prognathism in lucy, chimps more prognathic and humans orthognathic face

Sagittal crest/temporal lines

• Close together temporal lines (almost sagittal crest) in lucy, sagittal crest presence varies in chimps, widely spaced temporal lines in humans

Zygomatic arch

• Thick and laterally wide in lucy, narrow in chimps and humans

Post-orbital constriction

• Strong in lucy, stronger in chimps and not present in humans

Dental arcade

• angled teeth rows so intermediate inn lucy, parallel in chimps and parabolic in humans

Mandibular symphysis

• intermediate thickness in simian shelf + small slope in lucy, thick with sloping simian shelf in chimps and thin + vertical with no simian shelf in humans

How do the molars and premolars of gracile Australopiths compare to chimps and humans?

• In size the molars and premolars of Australopithecus are larger than both chimps and humans

• premolars are “molarized” in Australopithecus like humans: bicusped, ant-post expanded, no honing

What 2 features can be used to indicate the size of the temporalis muscle?

• Temporal lines/sagittal crest: this is where the temporalis muscle initiates

• Lateral width of zygomatic arches: the temporalis muscle fits behind the arch to connect to the coronoid process

What are the 2 main muscles involved in mastication?

• Temporalis muscle (temporal lines → coronoid process)

• Masseter muscle (ascending ramus → zygomatic process)

What cranial differences do we see between H.erectus and H.habilis?

Supraorbital torus

• larger shelf-like supraorbital torus (more developed supraorbital sulcus) in H.erectus

• less prominent in H.habilis

• both have double-arch

Prognathism

• stronger in H.habilis

• H.erectus almost orthognathic

Cranial vault

• Smaller and less round in H.habilis

• rounder and larger, football shaped from side in H.erectus

What cranial differences do we see between H.rudolfensis and H.erectus?

Supraorbital torus/sulcus

• Supraorbital sulcus present in H.erectus, not in H.rudolfensis

• Large shelf-like torus in H.erectus, smaller in H.rudolfensis

Sagittal keel

• Present in H.erectus, not in H.rudolfensis

Occipital torus

• Present in H.erectus, not in H.rudolfensis

H.rudolfensis has a large, flat face. It is wide particularly around the maxilla

List the key features of Sehelanthropus tchadensis

• Foramen magnum is intermediately positioned (between chimps and humans)

• Large brow ridges

• No sagittal crest

• Honing canines (but reduced compared to chimps)

List the key features of Orrorin tugenesis

• small molars (relative to chimps)

• curved phalanges

• Femur indicates bipedalism: long femoral neck, large femoral head, wide shaft

List the key features of Ardipithecus ramidus

• Abducted hallux

• Larger molars and premolars (than chimps, relative to size)

• No honing

• Foramen magnum anterior, inferior

• Long phalanges with bony ridges

What are the key features of Australopithecus afarensis

• Superior temporal lines

• Curved tooth rows

• No honing complex

• Wide, Large and anteriorly positioned zygomatic arch

• Human-like pelvis

What are the key features of Australopithecus africanus

• Large molars and premolars

• Reduced supraorbital torus (compared to aferensis)

• zygomatic positioned further anteriorly

What are the key features of Kenyanthropus platyops

• Large, flat face (NOT DISHED) + zygomatic positioned anteriorly

• small molars

• very wide maxilla

How can we differentiate between Australopithecus , Paranthropus and Homo skulls?

Australopithecus

• Larger post-canine dentition than homo, smaller than paranthropus

• No sagittal crest

• less zygomatic flaring than paranthropus

Paranthropus

• Large post-canine dentition

• Dished face

• Zygomatic flaring= large face

• Sagittal crest (variably present)

Homo

• Rounding of cranium

• Very reduced prognathism

• Reduced post-canine dentition

• Large cranial vault

What are the key features of Australopithecus anemensis

• Simian shelf present: mandibular symphysis (middle of mandible) thick and posteriorly sloped

• Parallel tooth rows

• Honing complex (in males)

• Buccolingually expanded molars

What are the key features of P.aethiopicus

• Very large sagittal crest (largest of paranthropus species)

• More posteriorly positioned zygomatic arches

• long skull

• face positioned in front of brain case

How can we differentiate between the species of Paranthropus

P. boisei is the MOST robust- widest zygomatic arches, largest M and P

P. aethiopicus is the intermediate: large sagittal crest, long skull with face positioned fully in front of brain case

P.robustus is the LEAST robust

H.habilis vs H.rudolfensis vs H.erectus skulls

H.habilis

• Supraorbital sulcus

• Small double-arches supraorbital torus

H.rudolfensis

• No supraorbital sulcus

• relatively small supraorbital torus

• Wide (especially maxilla) flat face

H.erectus

• Shelf-like large supraorbital torus

• Occipital torus

• Long skull (football from the side, teardrop from the top)

• Large cranial vault

• sagittal keel

• smaller dentition

• **+ major height increase

What are the key features of H.habilis

• Has a supraorbital sulcus

• Double arched, small supraorbital torus

• Smallest brain size/cranial vault of Homo species

What are the key features of H. rudolfensis

• No supraorbital sulcus

• Relatively small supraorbital torus

• Large, flat face (wide maxilla)

What are the key features of H.erectus

• Sagittal keel

• Shelf-like supraorbital torus + supraorbital sulcus

• Occipital torus

• Long skull (football from size)

H. erectus vs H. heidelbergensis skull

skull shape

• Long, low, stretched → H. erectus

• Higher, rounder → H. heidelbergensis

brain size (relative)

• Smaller → erectus

• Larger → heidelbergensis

brow ridge

• Straight, thick bar → erectus

• Segmented / double-arched → heidelbergensis

Occipital torus

• Prominent → erectus

• Variable, less prominent, more rounded cranium → heidelbergensis

What are the key features of Homo neanderthalensis

• Occipital bun

• Mid-face projection: puffiness in nasal and maxillary region

• Retromolar space: empty space behind m3 and M3

• Mental foramen is below m1

H. neanderthalensis vs H. sapiens skull/femur

Neanderthals

Skull

• occiptal bun

• mid-face projection

• retromolar space

• supraorbital torus

• mental foramen below m1

• small, sloped forehead

Femur

• Bowed anteriorly-posteriorly

• more robust

Humans

Skull

• mental foramen below p4

• canine fossa

• Boney chin

• large, vertical forehead

Femur

• less robust