News Bite: Cosmic rays date ancient human ancestor

Dating fossils might sound like Saturday night for a paleontologist, but it’s serious science! In a new study, a group of physicists and paleontologists teamed up to re-date one of the most complete skeletons of a human relative ever discovered.

The skeleton was discovered in a cave in South Africa twenty years ago, but the geology of the cave made it tough to figure out how long ago the animal, nicknamed “Little Foot” was washed in an buried. The date paleontologists were working with was 2 million years old, making this specimen that belongs to the genus Australopithecus a much younger animal than its cousin Lucy (Australopithecus afarensis).

Using a new technique that looks at how the atoms in the sand grains around the specimen changed after being sealed in the cave, away from cosmic ray bombardment, the team discovered the specimen is 3.67 million years old! That put the South African animal on the landscape at the same time as Lucy. That means two species of Australopithecus were wandering around at the same time. How did they share the landscape? Which species is more closely related to us? The paleontologists working on Little Foot are still getting it ready for a full anatomical description, but this new study presents a new way to date fossils once thought impossible to get an age from and makes us even more eager to know more about the anatomy of this ancient cousin of ours!

Little-Foot-Story

Check out this video if you want to learn more about the machine used by the physicists to date the sand around the Little Foot specimen:

The study:

Darryl E. Granger, Ryan J. Gibbon, Kathleen Kuman, Ronald J. Clarke, Laurent Bruxelles, and Marc W. Caffee. 2015. New cosmogenic burial ages for Sterkfontein Member 2 Australopithecus and Member 5 Oldowan. Nature. DOI:10.1038/nature14268

 

Filed under: Africa, Australopithecus, Cenozoic, Fossils, Geology, Hominids, Hominins, Human ancestors, Human evolution, New methods, Paleoanthropology, Paleontology, Paranthropus, Pliocene, Purdue University, South Africa

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