Lecture 11 - Aus. from E/C Africa Flashcards
1
Q
Aus. anamensis
general info
A
- 4.2 - 3.8 Ma
- Kenya/Ethiopia
- discovered by Meave Leakey & Kamoya Kimeu
2
Q
Aus. anamensis
postcrania evidence
A
- distal humerus found in 1960s
- complete radius, long
- tibia shows features associated with bipedalism
> enlarged lateral condyle
> bony buttness
> straight shaft - partial femur
> found in middle Awash
> no linea asper: muscle insertions that modern humans have (unlike Lucy)
3
Q
Aus. anamensis
dental evidence
A
- U-shaped dental arcade
> P3 is unicuspid
thick enamel
> compared to Ar. enamel which is thinner
> unites all individuals of Aus.
4
Q
Aus. anamensis
cranial evidence
A
- only one specimen, found in 2019
- relatively small brain
- more derived than cranium than Ar.
5
Q
Aus. anamensis
summary
A
- U-shaped dental (pleisomorphic)
- P3 unicuspid (pleisomorphic)
- thick enamel (australopith synapomorphy)
- bipedal (hominin synapomorphy)
6
Q
from anamensis to afarensis
A
anagenesis?
* mandibular inclination at the symphysis
* shape of P3 - radical ends are different once again, but middle traits are similar
* New date range (2019) means overlap of 100,000 years between the two species
7
Q
Aus. afarensis
general info
A
- ca. 3.9-2.9 Ma
- Ethiopia, Kenya, Tanzania
- Maurice Taieb & Donald Johanson, 1974
8
Q
aus. afarensis
general info/ discovery of Lucy
A
- 3.2 Ma
- Hadar, Ethiopia
- small girl, among the smallest of the Au. afarensis mandibles
- long arms, curved phalanges suggest arboreal adaptations
- lower limb shows strong evidence of bipedal locomotion
- debate about locomotion -> facultative versus bipedal predominant (carry-over)
9
Q
aus. afarensis
the first family
A
- Hadar A.L. 33 site
- c. 3.2 Ma
10
Q
aus. afarensis
size variation (sexual dimorphism)
A
- A.L. 822-1, ‘female’
> ape-like prognathic snout
small endocranial volume (<400-500 cc)
> unique supraorbital form
A.L. 444-2, ‘male’ - renewed research at Hadar shows fossils with intermediate morphologies
> ~400 specimens found at Hadar - estimated stature: ~3.5ft to 5.4ft
- estimated body mass: 55lbs to 150lbs
11
Q
locomotion debate
Laetoli Footprints
au. afarensis
A
- (almost) direct evidence that Laetoli hominins were bipedal
- c. 3.7 Ma, Tanzania
- recently discovered footprints at the site show evidence of sexual dimorphism
- scalpula is human-like in adulthood but gorilla-like in infancy
- femur is relatively short –> especially matters if you consider Orrorin evidence
- first evidence of a bicondylar angle
> chimps = hip joint, knee joint, foot = linear straight down - MTT & phalanges
> dorsoplantary explanded metatarsal bases (MTT)
12
Q
Selam, “Lucy’s baby”
A
- Dikika, Ethiopia
- 2.4 (~3 yr old girl)
- c. 3.3 Ma
13
Q
aus. afarensis
hand/tools
A
- Pad-to-pad precision grip is debated
- thumb length increased
- manual proportions intermediate between humans and great apes
- coincides w/ earliest evidence of butchery & changes in diet
14
Q
aus. afarensis
summary
A
- earliest hominin to be well-preserved
- variability = sexual dimorphism?
- variability in age of individuals allow to study development
- locomotion debated, some elements of arboreality & bipedalism
15
Q
au. bahrelghazali
general info
A
- Bahr el Ghazal, Chad
- ~ 3.5 Ma
- Only teeth/jaws
- First australopithecine west of Rift Valley
- Geographical variant of Au. afarensis?
16
Q
kenyathropus platyops
general info
A
- Found in 1998
- Lomekwi, Kenya
- c. 3.2-3.6 Ma
- Within Au. afarensis time span
- Wide midface
- Small postcanine teeth
17
Q
The Burtele foot
A
- Not attributed to a taxon!
- Evidence of diversity in locomotor patterns
- c. 3.4 Ma, Ethiopia
- Locomotor pattern similar to Ardipithecus
- Opposable hallux
18
Q
au. deyiremeda
general info
A
- c. 3.4 Ma, Ethiopia
- Teeth and jaws only
- More robust mandibular corpus and more vertical symphysis than Au. anamensis
- Seem to overlap substantially with Au. afarensis
- Potentially linked to Burtele foot…
