Early hominids

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Early hominids

• A.africanus
• A.robustus/A. boisei
• H.habilis

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SA dating techniques

• Chronometric techniques not possible in SA
• Correlate with Plio-pleistocene fauna at the East
  African sites
• Breccia
• Secondary deposits Bob Brain
• South African sites 4.4 1.5 mya

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Australopithecus africanus

• 3.6 to 1.4 mya (South Africa)
• 410 533 cc
• Increased cranial capacity
• Reduction in face and tooth size
• No semi-sectorial premolar, no canine diastema
• Descendants Homo and Robust australopithecines

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Little foot (3.6 to 4.4 mya)

• Sterkfontein Cave
• Ron Clarke team - 1998
• Evidence of hominid locomotion

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Taung child 2.0 mya

• Raymond Dart -1924
• Child between 3 4 years of age

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Mr (s). Ples (Sterkfontein)
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Mr (s) Ples (2.5 mya)
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"Robust"australopithecines

• 2.5 mya climate changes and becomes more dry/
  savannah
• Robust forms are seen in both East and South
  Africa
• Robust refers to cranial architecture while
  body size is the same as a. africanus

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A. robustus

• 2.0 to 1.5 mya
• Cranial capacity 587 cc
• Robust masticatory apparatus
• Grinding of hard foods seeds, tubers etc
• No descendants? contemporaneous with h. habilis

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Swartkrans 1.5 mya
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Mr. Ples (2.5 mya) Swartkrans (1.5 mya)
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A. boisei

• Hyper-robust hominids East Africa 2.3 to 1.0
  mya
• Zinjanthropus 1.75 mya (Olduvai)
• 60 size of a. aethiopicus
• No descendants, contemporaneous with H.habilis
• More specialized diet than a. robustus

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Genus Homo

• 2.3 to 1.5 mya
• Increase in brain size
• Posterior teeth decrease in size
• Elongated thumb, shortened fingers, precision
  grip (tool development)
• Visible anterior nasal spine
• Short cranial base, foramen magnum more
  anteriorly placed.

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Homo habilis

• Olduvai Gorge, Koobi Fora, South Africa
• 631 - 775 cm3
• Oldowan tool makers
• Immediate use
• Cores, crude flakes, hammerstones
• Ancestors a. africanus
• Descendants other early h.sapiens and h.
  erectus

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A. robustus H. habilis 12

• Sexual dimorphism used to assess taxonomic
  classifications
• Dental measurements (MD/BL) for 1st molars
• Modern humans and Vervets
• MD/BL ratio low in males (1.06 to 1.09) and high
  in females (1.11 to 1.14)

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A. robustus H. habilis 22

• A. robustus MD/BL ratio 1.08 0.06
• Early homo MD/BL ratio 1.13 0.07
• This suggests that some species assigned to A.
  robustus and early homo are conspecific

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Summary 12

• Pre-Australopithecines (7.0 to 4.4 mya)
• Sahelanthropus, Orrorin and Ardipithecus
• bipedal
• primitive dentition
• Australopithecines (4.2 to 3.2 mya)
• A. afarensis, A.africanus
• Small brain, large teeth, and bipedal

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Summary 22

• Australopithecines (derived) 2.5 to 1.4 mya
• "robust" australopithecines (paranthropus)
• Facial architecture
• Early Homo (2.4 to 1.8 mya)
• Decrease in dentition
• Greater encephalization

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Generalizations

• From the earliest hominids to homo habilis
• Efficient bipeds
• Increase in brain size relative to body
  size
• Decrease in tooth size
• Increase in the manipulation of tools