The world’s oldest known child that lived 3.3 million years ago had a human-like spine, showing it evolved much earlier than previously believed.
New analysis of two-and a half year-old Selam’s fossilised remains found she had only 12 pairs of ribs – fewer than in most apes.
The earliest humans climbed trees and walked on the ground. This flexibility helped them get around in diverse habitats and cope with changing climates.
The new study has found portions of human skeletal structure that enable efficient walking were established millions of years before it was thought.
Professor Zera Alemseged, who led the study, told MailOnline: ‘Up until our discovery, most of the suggestions were tentative if not speculative.
‘In our publication we are demonstrating, based on hard evidence for the first time that the human type of spine segmentation and number of vertebrae was human like by at lease 3.3 million years ago.’
The fossil, known as ‘Selam’ is the most complete spinal column of any early human relative, including vertebrae, neck and rib cage.
It was discovered in Dikika, Ethiopia in 2000 by researchers at the University of Chicago.
The spinal structure comes from a nearly complete skeleton of a two-and-a-half-year-old child who was from the species Australopithecus afarensis – the same species as the famous Lucy skeleton.
Recovered in the mid-2000s in Ethiopia, the skeleton is that of a small child, who was probably two or three at the time of death. It was buried in a flash flood and its bones were found in a big sandstone block.