Nickname: Mrs. Ples
Site: Sterkfontein, Republic of South Africa
Date of discovery: 1947
Discovered by: Robert Broom and John T. Robinson
Age: Between 2.5 and 2.1 million years old
Species: Australopithecus africanus.

STS 5, a nearly complete adult Australopithecus africanus, was an important fossil find because skeptics had previously argued that the Taung Child was actually a baby chimpanzee that would have gained its ape-like features when it got older. This fossil showed that maturity wouldn’t make A. africanus less human. The main difference between STS 5 and the Taung Child is that this fossil's face is strongly prognathic, an ape-like feature that becomes more pronounced as A. africanus individuals grow up.

STS 5 was nicknamed 'Mrs. Ples' by scientist Robert Broom after initially hypothesizing that she was a middle-aged female Plesianthropus transvaalensis, which was the original name of this species---thus, ’Mrs. Ples.’ This skull now thought to have belonged to a male.

Often found alongside animal bones, Australopithecus africanus was once considered a “killer ape.” Now we know that members of this early human species were sometimes eaten by predators. Living together in groups helped these early humans protect themselves.

Why dynamite is not necessarily the best way to excavate human remains.... do you see the wedge-shaped portion of the forehead reconstructed here in a light color? If you follow that crack around to the rear of the skull, you’ll see why scientists are much more careful today when excavating, or digging for human remains. Mrs. Ples’ skull was actually blown into two pieces during its extraction from the breccia (a cement-like rock) because Broom used dynamite to expose the remains over backbreaking work with a pickaxe.


  • Title: Australopithecus africanus skull (cast)
  • Location: Sterkfontein, Republic of South Africa
  • Type: Skull
  • Rights: This image was obtained from the Smithsonian Institution. The image or its contents may be protected by international copyright laws. http://www.si.edu/termsofuse
  • External Link: View this object record in the Smithsonian Institution Human Origins Website
  • Scientific Name: <i>Australopithecus africanus</i>
  • Photo Credit: James Di Loreto and Donald E. Hurlbert; Jennifer J. Hill, Smithsonian Institution National Museum of Natural History
  • Historic Period: Between 2.5 and 2.1 million years old
  • Field: Anthropology

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