— A skeleton named Little Foot is among the oldest hominid skeletons ever dated at 3.67 million years old, according to an advanced dating method.
Little Foot is a rare, nearly complete skeleton of Australopithecus first discovered 21 years ago in a cave at Sterkfontein, in central South Africa.
Previous dates ranged from 2 million to 4 million years old, with an estimate of 3 million years old preferred by paleontologists familiar with the site, said Darryl Granger, a professor of earth, atmospheric and planetary sciences at Purdue, who in collaboration with Ryan Gibbon, a former postdoctoral researcher, led the team and performed the dating.
Purdue University professors Darryl Granger (left) and Marc Caffee stand in front of the gas-filled magnet detector in the Purdue Rare Isotope Measurement Laboratory.
Stone tools found at a different level of the Sterkfontein cave also were dated at 2.18 million years old, making them among the oldest known stone tools in South Africa.
The detector was used to date the Little Foot skeleton.(Purdue University photo/John Underwood) Download Photo The dating relied on a radioisotopic dating technique pioneered by Granger coupled with a powerful detector originally intended to analyze solar wind samples from NASA's Genesis mission.The new date places Little Foot as an older relative of Lucy, a famous Australopithecus skeleton dated at 3.2 million years old that was found in Ethiopia.It is thought that Australopithecus is an evolutionary ancestor to humans that lived between 2 million and 4 million years ago.
Ronald Clarke, a professor in the Evolutionary Studies Institute at the University of the Witwatersrand who discovered the Little Foot skeleton, said the fossil represents Australopithecus prometheus, a species very different from its contemporary, Australopithecus afarensis, and with more similarities to the Paranthropus lineage."It demonstrates that the later hominids, for example, Australopithecus africanus and Paranthropus did not all have to have derived from Australopithecus afarensis," he said.