The Australopithecus bahrelghazali is an extinct species of hominid found to the west of the Rift Valley in 1995 and exhibited in 1996. It is estimated that lived 3-3.5 million years ago. He is also known as Abel, in homage to the Poitiers geologist Abel Brillanceau, who died shortly before the discovery of the fossils.
Their finding called into question the East Side Story hypothesis that the first bipedal hominids only came from the eastern Rift Valley, and forced anthropologists to consider that they represent a different Australopithecus line from the one that evolved into the Rift Valley. Homo.
Australopithecus bahreghazali jaw
At that time it was questionable to define a species with such a poorly varied sample of fossils. However, derived traits, new forms, feeding styles and characteristics in modes of movement encouraged researchers to give a new species a different name.
Because the species represented a paradigm shift for paleontology, there are those who still point out that, due to its particular characteristics, this extinct species should have been considered only a local variant of Australopithecus afarensis.
Discovery
Bahr el Ghazal, Chad, site of discovery of fossils
The Australopithecus Bahrelghazali fossil was found on January 23, 1995, in the Chadian town of Bahr el Ghazal, in Koro Toro, in the Djurab desert, in Chad. This area is located 2500 km from the Rift Valley.
The team led by Michel Brunet, director of the Laboratory of Human Paleontology at the University of Poitiers, France, found the anterior part of a mandible with five teeth: an incisor, two premolars and two canines, with a date of about 3 or 3.5 millions of years.
Four fossil remains of Australopithecus bahrelghazali are known, all of jaws, found in three different sites in the Koro Toro region, close to each other and equidistant from the areas of Ethiopia and Kenya. These two places are referential for the finds of Australopithecines of East Central Africa.
characteristics
The shape of the Australopithecus bahrelghazali jaw was parabolic and had an anterior region that did not have any type of nodule or protuberance configured by bone tissue, essential characteristics in the jaws of the genus Homo.
The teeth studied by the researchers had thick enamel. In the case of the frontals, they were large with high crowns and elongated roots.
Abel's third premolar has two cusps and three roots, while the fourth premolar is molarized. The upper third premolars had an asymmetric crown and three roots.
The fact that Australopithecus bahrelghazali had premolars with three roots and molarized with a more modern appearance, differentiates it to a great extent from the fossils of Afarensis, which had only two roots. In addition, the shape of the jaw is very different in both species.
On the other hand, Abel maintained primitive features, such as premolars with three flared roots as seen in the genus Paranthropus.
The premolars of this species resemble those of humans: the front part of the jaw was reduced and was almost vertical.
Height and build
According to anthropological analysis, this species could have reached 1.20 to 1.40 meters. They were mostly small in size and thin build; some anthropologists defined them as quite fragile specimens.
In addition, experts point out that in Abel's case there was a marked sexual difference between males and females, with the size of the males being significantly larger than that of the females.
Cranial capacity
With the small amount of fossils found of the Australopithecus bahrelghazali species, it is impossible to ascertain without a doubt what its cranial capacity or its phylogenetic position was.
However, it is known that the brain of most Australopithecus species was around 500 cc, 35% of the size of the brain of modern man.
In this context, it is worth indicating that, although they presented many characteristics considered primitive, their movement or locomotion was carried out on two of their legs, which can provide information on the evolutionary level of the species.
Tools
Scientific studies carried out revealed that for more than three million years most hominids used implements to cut meat and separate it from the bones to which it was attached, which is why it is believed that this was the case of Australopithecus bahrelghazali.
This conclusion came from the discovery of two bone fossils that had marks that were made by a tool with sharp features.
The study suggests that, at the time when the animals to which the bones belong lived, hominids used instruments such as quite sharp stones that served to detach the marrow or remove the meat adhering to the bones.
Australopithecus afarensis was probably the first species to use tools.
Feeding
The diet of this species was mainly composed of fruits, vegetables and meat. This information was provided by various studies that have been carried out on the carbon isotopes present in hominid teeth.
Scientists have pointed out that Australopithecus bahrelghazali focused its diet on forest plants, which included varieties of tropical grasses and sedges.
Sedges belong to a species of grass-like plant that grows 8 to 12 centimeters in grasslands and leaves some particular marks on the teeth of animals. Abel is the oldest example of an ancestor of humans who may have ingested these types of plants.
Habitat
After the studies carried out, it was determined that this species lived in areas near lakes, surrounded by forests, wooded savannas and grassy areas.
The discovery of this species shows clear evidence that three and a half million years ago the Australopithecines had experienced particular situations of great intensity in East Central Africa (such as some type of radiation), which forced them to move, crossing the geographical barrier that was the Rift Valley.
The discovery of Abel was very important in this regard, since once the discovery was made, doubts arose about the most primary origin of Australopithecus.
References
- Mosterín, Jesús (2006) "Human nature." Retrieved on September 6 from the University of Seville: institutional.us.es
- Arsuaga, JL (2006) "The chosen species" Retrieved on September 6 from the Confederation of Scientific Societies of Spain: cosce.org
- "Australopithecus bahrelghazali". Retrieved on September 6 from Wikipedia: wikipedia.org
- Australopithecus bahrelghazali. Retrieved on September 6 from Encyclopedia Britannica: britannica.com
- Australopithecus Bahrelghazali. Retrieved on September 6 from Australian Museum: australianmuseum.net.au