A three-million-year-old skeleton of a three-year-old child has been uncovered in Dikika in Ethiopia.
The child, probably female, belongs to Australopithecus afarensis , an ancient pre-human species that lived around three to four million years ago and includes the famous 'Lucy' skeleton found in Ethiopia in 1974. However, this new fossil is actually about 200,000 years older than Lucy.
The skeleton is remarkably complete for such an ancient pre-human specimen. It includes a well-preserved face, brain case, lower jaw and all but two of the teeth, including unerupted teeth still in the jaw.
'This is a very special find,' said Chris Stringer, human evolution expert at the Natural History Museum. 'It's not until we come to intentional burials by Neanderthals and modern humans in the last 100,000 years that we otherwise find such well-preserved infant remains, because of their fragility.'
The specimen reveals the child had many morphological similarities to African apes such as in the hyoid bone found in the throat. This is the first time a hyoid bone has been found from this time period. Clues from her feet and lower limbs show she could walk upright but her gorilla-like scapula and long and curved phalanges or finger bones suggest that she also climbed trees.
Chris adds, 'The new fossil reinforces the view that the australopithecines (southern apes) were human-like in the lower part of the body (hips, legs, feet) but still rather ape-like in the upper part (shoulder, arms, hands), walking on two legs when on the ground, but retaining the ability to climb in the trees.'
The infant was found in sediments at the bottom of a slow-flowing channel between a river and a lake. The slow flow of water buried the body intact and the sediment flowing in the water would have quickly covered it up, helping to preserve her so well.
Zeresenay Alemseged, from the Max-Planck Institute for Evolutionary Anthropology in Germany, spent thousands of hours carefully removing the hard sandstone that encased the skeleton.
A. afarensis was a possible ancient human ancestor that lived three to four million years ago. This species existed at an important time in human evolution sharing similarities with both apes and humans.
'This infant australopithecine is a very valuable addition to the hominin fossil record,' said Louise Humphrey, human evolution expert at the Natural History Museum.
'The skeleton is exceptionally well preserved and promises to reveal an enormous amount of information about the lifestyle of this young australopithecine.'
'The skeleton and dentition (teeth and jaws) can provide remarkable insights into how australopithecines developed and advance our understanding of when modern human growth and life history patterns evolved.'
This research is reported in the journal Nature .