A. afarensis had a slender physique, resembling a young individual of the African Australopithecus Australopithecus africanus. A. afarensis is believed to be more closely related to the genus Homo (which includes the modern human species, Homo sapiens), being either its direct ancestor or a close relative of an unknown ancestor. Some researchers include A. afarensis in the genus Praeanthropus. There is no photo of the Afar Australopithecus, but those who want to understand what this animal looked like can enjoy unique illustrations and mock-ups that reconstruct the appearance of this primate. Modern technologies work wonders, because thanks to them, the appearance of Australopithecus was reconstructed using computer graphics in many documentaries.
The most famous fossil of Afar Australopithecus is a partial skeleton nicknamed Lucy (3.2 million years old), found by Donald Johanson and his colleagues, who during their work repeatedly included the Beatles song “Lucy in the Diamond Sky”.
Discovery story
Australopithecus afarensis fossils have been discovered only in East Africa. Despite the fact that the Laetoli region is a typical locality for Afar Australopithecus, the most extensive remains attributed to this species are found in Hadar, the Afar region of Ethiopia, including the aforementioned partial skeleton “Lucy”.
Compared to modern and extinct large monkeys, A. afarensis had shrunken fangs and molars, although they are still relatively larger than in modern humans. Full-length photographs of Afar Australopithecus (or rather, its reconstructions) show that these animals were much lower than modern humans. A. afarensis also has a relatively small brain size (about 380-430 cm 3 ) and a prognathic facial structure with jaws protruding forward.
Bipedality
Significant debate in the scientific world was conducted mainly about the locomotor behavior of Afar Australopithecus. Some studies show that A. afarensis was almost exclusively bipedal, while others suggested that these creatures were partially arboreal. The anatomy of the arms, legs, and shoulder joints is largely consistent with the latest interpretation. In particular, the morphology of the scapula appears monkey-like and is very different from that of modern humans. The curvature of the fingers and toes (phalanges) approaches the curvature of modern monkeys and suggests their ability to effectively grab branches and climb trees on them. Alternatively, reducing the size of the big toe and, therefore, losing the ability to grab objects with the feet (a feature of all other primates) suggests that A. afarensis has lost climbing ability.
A number of features in the skeleton of Afar Australopithecus strongly reflect bipedalism. In addition, some researchers had previously suggested that bipedality developed long before A. afarensis. In general anatomy, the pelvis is much more human-like than the ape-like. The ilium is short and wide, the sacrum is also wide and is located directly behind the hip joint. Strong attachment to knee extension is evident. While the pelvis is not fully humanoid (being noticeably wide or branched, with laterally oriented iliac bones), these features indicate a structure that can be considered radically reconstructed specifically to adapt bipedality to the locomotor repertoire of this animal.
Ecology
Climatic changes about 11-10 million years ago affected forests in East and Central Africa, establishing periods when gaps in forest branches impeded normal life at the canopy of trees, because animals could not even normally hide from the rain. During such periods, proto-hominids could take up vertical walking for ever-increasing ground travel, while the ancestors of the gorillas and chimpanzees continued to specialize in climbing vertical trunks of trees and creepers with a bent thigh and a gentle knee. This differential development within the larger community of hominids led A. afarensis to be adapted to vertical bipedalism for extensive hiking trips, while still using, of course, the ability to climb small trees. Nevertheless, protogominids and ancestors of chimpanzees and gorillas were the closest relatives, and they had similar anatomical features, including the same wrists.
Earliest hominids
Some studies suggest the presence of a vertical spine and predominantly vertical body structure even in primates belonging to the species M. bishopi in the early Miocene 21.6 million years ago, the earliest human primates. Known from fossils found in Africa, Australopithecus is a group from which the ancestors of modern humans came from. It is worth noting that the term “Australopithecus” often covers all early hominid fossils from about 7 million to 2.5 million years ago, as well as some later hominids that lived from 2.5 to 1.4 million years ago. After this period, Australopithecus is already considered extinct.
Sexual dimorphism and social behavior
One of the best indicators of the social behavior of extinct fossil species is the size difference between males and females (sexual dimorphism). By comparison with the behavior of modern monkeys and other animals, the reproductive behavior and social structure of Afar Australopithecus can be assumed. One of the difficulties is that the average body size difference between a man and a woman A. afarensis varies greatly from skeleton to skeleton. Some suggest that the males are significantly larger than the females, and outwardly slightly similar to gorillas and orangutans. If A. afarensis is characterized by the same relationships between sexual dimorphism and the structure of social groups as modern gorillas, then these creatures may have lived in small family groups, including one dominant male and several breeding females. Other studies have shown that the sizes of females and males of Afar / African Australopithecus do not differ too much - thus, in this respect, they were more similar to modern people. Much more than modern monkeys.
Afar Australopithecus: traces of material culture
For a long time, none of the known discovered stone tools associated with A. afarensis, and paleoanthropologists usually believed that stone artifacts belong only to hominids that appeared after 2.5 million years ago. However, a 2010 study suggested that some species of early hominids ate meat, cutting it off from animal carcasses with primitive stone tools.
Further findings in Afar, including many hominid bones in this area, led to the assumptions of Johanson and White that individuals from the Koobi-Fora region coincided with individuals from Afar. In other words, Lucy was not unique in terms of bipedalism and a flat face shape - these features arose among many Afar Australopithecus living in this region.
Modern hominids
In 2001, Mike Leakey proposed introducing a new genus and species for the fossil skull, labeled KNM WT 40,000. The fossil skull seems to have a flat face, but its remains are highly fragmented. It has many other characteristics similar to A. afarensis residues. He is still the only representative of his species and kind, and its owner lived approximately at the same time as the Afar Australopithecus, period.
Another new species, called Ardipithecus ramidus, was found by Tim White and his colleagues in 1992. It was a completely bipedal animal that lived from 4.4 to 5.8 million years ago, but seemed to live in a forest environment.