Lecture 12 - Souther African Australopithecus Flashcards
1
Q
sites
formation of south african sites
A
- Cave sites, formed as layers of bedrock were dissolved and filled with sediments
- No volcanic ash layers → chronometric dating is extremely difficult
2
Q
sites
S vs. E African site differences
A
S. Africa
- Cave sites
* Fossils often found in breccia
* Easier to say fossils may be from one individual
E. Africa
* Open sites
* Fossils erode out, sometimes surface finds
* Harder to definitely say fossils may be from one individual
3
Q
au. africanus
general info
A
- c. 3.7 - 2 Ma
- South Africa
4
Q
au. africanus
fossil discoveries - Piltdown Man
A
- robust mandible
- Large teeth
- Large brain
- Associated with primitive tools
- Eoanthropus dawsonii
- Charles Dawson
HOAX
5
Q
au. africanus
Taung Child
A
- Small brain
- Modern/small teeth (small canine)
- natural endocast (rare)
- Foramen magnum is anterior
- Australopithecus africanus
- Found in Taung, South Africa in 1924
- Raymond Dart
6
Q
au. africanus
“Mrs. Ples”
A
- Sterkfontein, SA, c. 2 Ma
- May be male!
- Very prognathic
7
Q
au. africanus
STS 14
A
- Sterkfontein, SA, c. 2.5 Ma
- One of several associated skeletons
- adolescent
- Biped - pronounced lumbar curve
8
Q
au. africanus
killer apes
A
- Found with large amount of animal bones
- “Osteodontokeratic culture”: Hunting made apes into humans
9
Q
au. africanus
subsistence
A
- Modern interpretations portray this hominin as prey, not hunter!
- Several of the broken bones were broken by natural processes
- A. africanus was probably largely a vegetarian
10
Q
au. africanus
comparisons
A
- Smaller cranial capacity than A. afarensis
- Reduction in dentition and more parabolic arcade than A. afarensis
- Obligate biped
- Shows more adaptations to arboreal locomotion than A. afarensis
- Prognathic (but STS 5 is exceptionally prognathic)
11
Q
A. prometheus
A. prometheus debate - “Little Foot”
A
- Sterkfontein, SA
- 3.7 Ma
- Oldest Southern African hominin
- Foot discovered in 1980
- Then 90% complete skeleton discovered in 1998, Finalized in 2018!
- eldery female
- relatively long legs
- still somewhat opposable thumbs
- small brain size
- debated taxonomy - africanus vs prometheus
12
Q
au. sediba
general info
A
- c. 1.98 Ma
- Malapa, SA
- Key fossils: MH1, MH2
- Mosaic morphology
- Likely descends from A. africanus
- Close relative of Homo?
- MH1 - subadult male (12-13 yrs old)
- MH2 - adult female
13
Q
au. sediba
crania
A
- Cranium only present for MH1
- Small cranial capacity
- Slightly prognathic
- Relatively small dentition (MH1 and molars for MH2)
14
Q
au. sediba
hand
A
- one of the most complete hands in fossil record
- well developed flexor sheath ridges (strong flexion, arboreal trait)
- expanded apical tufts - precision gripping
- strong FPL attachment - good thumb flexion/loading (primitive or convergent evolution to Orrorin & Ardi?)
15
Q
au. sediba
thumb
A
- Very long thumb relative to third digit
- Long thumbs have been suggested to be related to tool use
- But no stone tools have been found at Malapa (yet)
16
Q
au. sediba
pelvis
A
- Sciatic notch
- Iliac blades lateral, but more vertical (Homo-Australopithecus-like)
- Larger lumbosacral angle (Homo-like)
- Likely influenced by locomotion, not obstetrics
17
Q
au. sediba
summary
A
- Mosaic of primitive and derived features
- Bipedal
- Small cranial capacity
- Very long thumb
- Observations made on two specimens (one subadult male and one adult female)
