Australopithecus deyiremeda was a hominid who walked the Earth at the same time as the well-known Australopithecine Lucy. Fossils of the previously unknown species have been discovered in Ethiopia, adding to the diversity of known human ancestors.
Fossils of teeth and jaws from at least three individuals were discovered within clay in the Afar region of that nation. Although some characteristics of the fossils were similar to other predecessors of Homo sapiens, the samples were recognized as belonging to a previously unknown species of human ancestor.
The newly discovered species possessed both human-like and ape-like qualities, as did Australopithecus afarensis, the species to which Lucy belonged. Based on the relatively small size of the teeth discovered, researchers believe that A. deyiremeda looked more like modern humans than did Lucy and members of her species. Each of these human ancestors lived between 3.5 and 3 million years before our own time.
This discovery marks the first time that two different species of human ancestors were found to be living together at the same time and place before the evolution of our own genus, Homo.
"The new species is yet another confirmation that Lucy's species, Australopithecus afarensis, was not the only potential human ancestor species that roamed in what is now the Afar region of Ethiopia during the middle Pliocene," said Yohannes Haile-Selassie, curator of physical anthropology at The Cleveland Museum of Natural History.
The new finding could help scientists learn more about human ancestors in the ancient past, millions of years in the past, as primates became more intelligent.
One of the great questions coming from the find is determining how the two species coexisted. Researchers believe these populations may have been bitter rivals if they were each foraging for the same resources in the wild. Examination of the dental evidence suggests that Lucy and her ilk may have eaten a diet far different than that consumed by deyiremeda. Kenyanthropus platyops, another ancient relative of human beings, also lived fairly close to the two species of Australopithecus at around the same time.
Lucy was unearthed in 1974, from a site just 30 miles away from the location where the new species was discovered.
Our own species, Homo, first evolved about 2.8 million years ago, and the first true Homo sapiens were born roughly 200,000 years before our own time. At one time, researchers believed just a single species of human ancestor existed at any given time in the period between three and four million years ago.
"The story is becoming more complicated as more branches are added to the human phylogenetic tree," said Stephanie Melillo of the Max Planck Institute for Evolutionary Anthropology.
Discovery of Australopithecus deyiremeda was detailed in the journal Nature.
Photo: Tim Evanson | Flickr