New insights into half-human, half-ape skeletons found in South Africa reveal a potential missing link that may require a rewrite of the story of human evolution.
The species, called "Australopithecus sediba," had human-like teeth, a pigeon-toed walk, subsisted mostly on vegetables and spent much of their time in trees. A new paper describes how the species behaved and looked.
"Sediba shows a strange mix of primitive australopithecine traits and derived Homo traits - face and anterior dentition like Homo, shape of the cranium like Homo, other parts of the face and size of the cranium like an australopithecine, arms like an australopithecine, pelvis and lower limbs like Homo and feet and ankles like an australopithecine," project leader Lee Berger told Discovery News.
The precursor to "Homo erectus" was long considered to be "Homo habilis," however the new research indicates that "Au. sediba" may be a more likely forebear, given its humanlike qualities and the fact that it existed almost 100,000 years before "Homo habilis." Specifically, an examination of the skeletons' dental structure reveals that it is classified separately from "Au. afarensis," a species that includes the skeleton Lucy found in 1974.
According to Berger, "Au sediba" embodies a "ghost lineage" that is completely separate from what was once thought to be the precursor to modern humans.
"Everywhere we look in these skeletons, from the jaws on down to the feet, we see evidence of the transition from australopith to 'Homo,' " co-author and Texas A&M University professor Darryle de Ruiter said in a statement. "Everywhere we see evidence of human evolution."
" 'Au sediba' looks more like 'Homo' than any other australopith known," de Ruiter wrote in an e-mail to The Verge, "and for this reason represents an excellent candidate ancestor for the genus 'Homo.' "
Though debate over human evolution in Africa will certainly continue, the new research could help illuminate these alternative theories.
"We thought we knew how this part of human evolution worked, and sediba comes along and says, 'Here's another option,' " Berger said.
In other human evolution news, the Neanderthal genome was published in late March. Though the genome was sequenced before, this new genome by German researchers was of a much higher quality that allowed for greater detail.
