Scientists announced Wednesday the discovery of an almost complete skull of an early human ancestor in Ethiopia, which lived 3.8 million years ago, and displayed a fascinating blend of apelic and human-like features, providing insight into a crucial period for evolutionary descent, the eventually led to the modern man, the species Australopithecus anamensis, which first appeared about 4.2 million years ago.
This species is considered a direct ancestor of the Australopithecus afarensis, the best known by the famous partial skeleton nicknamed Lucy, which was excavated in 1974 about 56 km from the site in the Afar region of Ethiopia, where the MRD skull 201
MRD and Lucy collect water divisional fossils to illuminate early human ancestors.
"This is a unique discovery, and there was nothing that could have been done. This is exciting," said paleoanthropologist Yohannes Haile-Selassie of the Cleveland Museum of Natural History, a director of research published in the journal Nature. "We are talking about the most complete skull of an early human ancestor ever found in the fossil record that is over 3 million years old."
Previously, the only cranial remnants of Australopithecus anamensis were isolated jaw fragments and teeth that made it difficult To remove these Understand the species completely. The skull is crucial for learning nutrition, brain size and facial appearance of a species.
The discovery allows scientists to give a face to the name Australopithecus anamensis, said paleoanthropologist and study co-author Stephanie Melillo of the Max Planck Institute for Evolutionary Anthropology in Germany.
"The anatomical features of this skull help us to characterize this species, which in turn affects our understanding of evolutionary relationships between species," added Melillo.
MRD's species, which was bipedal but possibly also able to move in trees, was much smaller than modern humans.
Her skull, which was found about 550 km northeast of Ethiopia's capital, Addis Ababa, measures about 20 cm from front to back and 11.5 cm wide. Earlier research suggested that the species had reached a height of about 1.5 meters, but the researchers did not give a size estimate for this individual, apparently an adult male.
& # 39; A PRIMITIVE FACE & # 39;
The upper jaw emerging from the ground was the first piece found that restored the rest of the skull.
"What we see in the new skull is like a primitive face," said Haile-Selassie.
It had a sturdily built and long face with protruding pines and a well-developed "sagittal crest", a crest of bone on the head, indicating strong jaw musculature. The researchers said it apparently lived in a dry scrubland near a river delta and a lake.
It dates back to between 4.1 million and 3.6 million years, when fossils of early human ancestors were exceptionally rare.
The evolutionary lineage that led to humans Separated from the chimpanzee lineage about 6 million to 7 million years ago, it gradually acquired features such as bipedal walking, flatter face, and larger brain size through a number of species. Our species, Homo sapiens, appeared in Africa about 300,000 years ago.
In scientific usage, the MRD species was a hominin, a group of modern humans, extinct human species, and immediate ancestors, including various Australopithecus species. The MRD skull shows a combination of primitive features of older species and properties similar to those of later hominins.
MRD has some primitive features that resemble those of a previous group called Sahelanthropus, including a long and narrow form of the brain and the shape of the back of the skull where the neck muscles attach.
MRD also shows a reduction in dog size in older species, although these teeth are still larger than Lucy's species, as dog size decreases progressively among later hominins. Some aspects of the face indicated features in later types, such as the structure of the cheekbones anchoring important masticatory muscles.
So far, the earliest Australopithecus anamensis fossils were 3.9 million years old. The age of the MRD fossil indicates that this species lived together with Lucy's species for approximately 100,000 years, which challenged earlier ideas that the earlier species had evolved to the later ones without overlap.
"The fact that these two closely related species overlap Both temporally and spatially, they raise new questions as to whether they compete for resources such as food or space. "
" We see here that our evolution was not completely characterized by a linear transformation from one species to another, "added Haile-Selassie.
(This story was published in a feed of the news agency without text changes, only the title has been changed.)
August 29, 2019 07:59 IST