Skull of oldest-known human ancestor identified
August 29, 2019 - Palaeontologists have excavated a near-complete skull of an early human ancestor that lived 3.8 million years ago. Until now the only cranial remains of Australopithecus anamensis were jaw fragments.
The fossil has been dubbed MRD by a team led by Ethiopian paleoanthropologist Yohannes Haile-Selassie of the Cleveland Museum of Natural History in Ohio. The team have identified MRD as a hominin believed to be the direct predecessor of the famed “Lucy” species, A. afarensis.
In 2016 an Ethiopian goat herder unearthed MRD about 56km (35 miles) from of the site in the Afar region of Ethiopia where the famous partial skeleton of Lucy, which dates from about 3.2 million years ago, was unearthed in 1974.
The new fossil could reshuffle that ancient relationship; the authors argue this week in the journal Nature.
Researchers hail the skull as one of the most significant hominin discoveries in decades. MRD measures about 20cm (8 inches) front to back and 11.5cm (4.5 inches) wide. Previous research suggested the species reached about 1.5 metres (5 feet)tall, but the researchers did not give a height estimate for MRD, an adult male.
The species that led to modern humans split from the African apes some 6-8 million years ago. Our ancestors gradually acquired traits such as bipedal walking, flatter face and increased brain size. Homo sapiens appeared roughly 300,000 years ago in Africa.