ATH 351-01

Dikika Child

age & sex estimation

  • dental CT scans
  • unerupted teeth
  • fit into lower range of australopithecine tooth size
  • indicates female sex
  • approx. 3 years old, est.
  • growth & development closer to chip than human
  • brain volume ~300cc

Lucy’s contemporaries

  • Kenyanthropus platyops
    • flat-faced man
    • fragmented skull
    • 3.5mya Kenya
  • Australopithecus bahrelghazali
    • resembles A. afarensis
    • mandible & teeth
    • 3.5mya Chad

“Little Foot”

  • species unknown
    • complete skeleton
    • partly divergent big toe
    • 3.3mya S. Africa

Darwin program tonight ch 16, Darwin’s Darkest Hour

Evolutionary significance chart

alternative phylogenies

  • A. afarensis is common ancestor of other Australopithecines and humans
  • A. afarensis is not ancestral to A. africanus

Ardipithecus ramidus – origin of bipedalism – oldest hominin fossil skeleton known

  • remains of 36 individuals available
  • ARA-VP 6/500
  • 110 specimens
  • oldest confirmed
  • originally called Australpithecus ramidus, changed later
  • discovered Aramis, Ethiopia (western Afar Rift)
  • 6000 other species fossils discovered in same strata, indicates woodland environment
  • kills savannah hypothesis
  • 4.4mya, via argon dating

Pelvis & femur – graphics

  • wide, flaring pelvic ilia
  • lower pelvis apelike
  • insertion points for muscle indicate large glutes, indicative of bipedalism
  • insertion points for large hamstring, indicative of climbing

Pelvis comparison chart

hand & foot bone comparison

arms & legs approx. same size: intermembral index .95

no evidence for brachiation or knuckle-walking

Os peroneum limits big toe abduction

Ardi’s skull & dentition

  • cranial capacity
  • incisor breadth
  • postcanine length
  • maxillary canine height
  • lower face prognathic but not like chimp
  • looks similar to Sahelanthropus
  • no canine premolar honing complex

skeletal diagram

phylogenetic significance chart

last common ancestor Humans shared with chimps

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