- Title: Fossil discovery reveals face of human ancestor
- Date: 28th August 2019
- Summary: HOUSTON, TEXAS, UNITED STATES (FILE - AUGUST 28, 2007) (REUTERS) 3.2 MILLION YEAR-OLD FOSSIL FRAGMENTS OF "LUCY" LAID OUT IN CASE JAW BONE RIB AND SPINE FRAGMENTS MODEL RECONSTRUCTION OF HOW LUCY MIGHT HAVE LOOKED AS AN ADULT
- Embargoed: 11th September 2019 17:34
- Keywords: Cleveland Museum of Natural History Australopithecus anamensis Lucy fossil human evolution paleontology
- Location: ADDIS ABABA / AFAR REGION, ETHIOPIA / UNIDENTIFIED LOCATION / HOUSTON, TEXAS, UNITED STATES
- City: ADDIS ABABA / AFAR REGION, ETHIOPIA / UNIDENTIFIED LOCATION / HOUSTON, TEXAS, UNITED STATES
- Country: Ethiopia
- Topics: Life Sciences,Science
- Reuters ID: LVA002AU4VD53
- Aspect Ratio: 16:9
- Story Text: Scientists on Wednesday (August 28) announced the landmark discovery in Ethiopia of a nearly complete skull of an early human ancestor that lived 3.8 million years ago, a species that possessed an intriguing mixture of ape-like and human-like characteristics.
The fossil dubbed MRD, which provides insight into a pivotal period for the evolutionary lineage that eventually led to modern humans, belongs to the species Australopithecus anamensis, which first appeared roughly 4.2 million years ago.
This species is considered the direct ancestor of Australopithecus afarensis, the species best known from the famous partial skeleton nicknamed Lucy unearthed in 1974 about 35 miles (55 km) from of the site in the Afar region of Ethiopia where the MRD skull was unearthed in 2016. Lucy dates from about 3.2 million years ago.
MRD and Lucy together stand together as watershed fossils for illuminating early human ancestors.
"This is really a game changer in a lot of ways and answers all the questions that we've had lingering around for decades," said Cleveland Museum of Natural History paleoanthropologist Yohannes Haile-Selassie, a leader of the research published in the journal Nature.
Until now, the only skull remains of Australopithecus anamensis were isolated jaw fragments and teeth, making it tough for scientists to fully understand the species. The cranium is critical for learning about a species including its diet, brain size and facial appearance.
The new discovery finally allows scientists "to put a face to the name" regarding Australopithecus anamensis, said paleoanthropologist and study co-author Stephanie Melillo of the Max Planck Institute for Evolutionary Anthropology in Germany.
MRD's species was much smaller than modern humans. Its skull, found about 340 miles (550 km) northeast of Ethiopia's capital Addis Ababa, measures about 8 inches (20 cm), front to back, and 4.5 inches (11.5 cm) wide. Previous research has suggested the species reached about 5 feet tall, but the researchers did not give a height estimate for this individual, apparently an adult male.
The MRD fossil hails from a time between 4.1 and 3.6 million years ago when early human ancestor fossils are exceptionally scarce.
The evolutionary lineage that led to people split from the chimpanzee lineage roughly 6 million to 7 million years ago, gradually acquiring traits such as upright walking, flatter face and increased brain size through a succession of species. Our species, Homo sapiens, first appeared about 300,000 years ago in Africa.
The upper jaw, sticking out of the ground, was the first piece found, leading to the recovery of the rest of the skull.
In scientific parlance, MRD's species is a hominin, a group consisting of modern humans, extinct human species and immediate ancestors including the various Australopithecus species. MRD's skull possesses a combination of primitive traits seen in earlier species as well as characteristics resembling those in later hominins.
The researchers said it apparently inhabited arid shrub land near a river delta and lake.
Until now, the oldest Australopithecus anamensis fossils were 3.9 million years ago. The age of the MRD fossil indicates this species co-existed for approximately 100,000 years with Lucy's species, challenging previous notions that the earlier species had evolved into the later one with no overlap.
"Rather, the ancestor, the potential ancestor, Australopithecus anamensis, and its descendant, Australopithecus afarensis, actually overlapped in time, at least for a hundred thousand years between 3.9 and 3.8 million years ago. So, this is a major discovery in terms of how we understand the phylogenetic relationships between those two," Haile-Selassie added.
Previous fossils showed the configuration of the ankle joint in Australopithecus anamensis was indicative that it was bipedal. There is some debate about whether other anatomical traits indicated it also still was adapted to living in the trees like earlier species. - Copyright Holder: FILE REUTERS (CAN SELL)
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