Australopithecus Anamensis: Characteristics, Skull, Habitat

The Australopithecus anamensis is a hominid species whose bones were found in Kenya in 1965, although at that time was not recognized as a new species. It was described as a new species in 1995 and is believed to be between 3.9 and 4.2 million years old. The exact site of the discovery was Lake Turkana and from there it derives its name, since the word anam in Turkana language means “lake”.

It was the year 1965 when a group of explorers – led by Bryan Patterson of Harvard University – discovered in an excavation located in Kanapoi, northern Kenya, what looked like a bone belonging to a primitive human arm.

Patterson could not locate other pieces in the place so, although he thought it was an important find, he could not reliably determine what species it was. 

In 1994, an expedition led by British-Kenyan Meave Leaky, a member of a three-generation family of paleoanthropologists based in Kenya, found numerous bone and tooth fragments near the same site.

The site became renowned, as it served to dispel Patterson’s doubts and establish that it was certainly the remains of a new species with an impressive date that ranged from 3.9 to 4.2 million years.

This new species was named Autralopithecus ( australis , which means “from the south”; and pithekos , which means “monkey”) anamansis ( anam means lake in the local language), due to the proximity of the excavation site to Lake Turkana.

The Autralopithecus corresponds to a genus of hominid primates that includes seven species: afarensis , africanus , anamensis , bahrelghazali , deyiremeda , garhi and sediba . They lived in Africa for more than 3.9 million years and until about 2 million years ago, when their extinction is estimated.

Physical and biological characteristics

The most remarkable thing about Australopithecus is that they moved bipedally. Although they still retained the ability to climb through foliage and vegetation, they could already stand on two feet without difficulty, alternating walks with movements through the trees.

The size of their brain was similar to that of today’s great apes, reaching an average capacity of 500 cc. Their appearance was quite similar to that of current chimpanzees.

It is estimated that these individuals were about the size of a chimpanzee (between 1.2 and 1.5 m) and weighed between 40 and 50 kg. The females were much smaller than the males and lived in the tropics of Africa, feeding on seeds, fruits and leaves.

Some researchers and scientists are inclined to classify Australopithecus afarensis and anamensis in a separate genus called Paranthropus , due to the size of their fangs and their flat face.

From the studies carried out on the humerus, tibia and femur fragments —some found later—, it is known that they are the oldest references of hominids that walked upright and on two legs.

Feeding

He could eat both typical foods from open spaces (seeds, reeds, herbs, among others) and fruits and tubers . He used stone tools with which he was able to tear and even fracture bones to take advantage of the marrow.

Their long arms and the shape of their wrist bones suggest that these individuals probably climbed trees, while also being able to walk for medium distances.

Teeth

Their jaws were characterized by being quite strong and at the same time somewhat narrow. For their part, the teeth were hard and had enamel.

The latter suggests that, in addition to feeding on plants, fruits and tubers, they also did so on nuts and other types of seeds that required powerful jaws to crush.

Cranial capacity

The brain of most Australopithecus species was around 35% (500 cc) the size of the brain of modern man, Homo sapiens .

The Australopithecus are a more modern kind of primates that Ardipithecus , of those considered successors. The main distinguishing features of this genus compared to other hominids are found in its skull and teeth.

The Australopithecus had a comparatively greater cranial capacity, of about 500 cc compared to the 300 cc of the Ardipithecus , who are estimated to be their direct predecessors.

It can be said with certainty that Australopithecus were completely bipedal thanks to the position and the way of connection of the spinal cord with the brain in the area of ​​the skull.

In contrast, the Ardipithecus had the ability to walk bipedally but for short distances, and usually combined with movement on all fours. As for their teeth, they had small-sized fangs, comparing them with those of their ancestors, as well as with current apes.

Instruments

Even with their limited brains, Australopithecus already showed skills – albeit archaic – to make tools that they used to facilitate the handling of their food and to defend themselves or to ward off animals that could threaten them.

Habitat

The Australipithecus anamensis is considered to be the direct ancestor of the Australopithecus afarensis , typified species with the discovery of the famous Lucy in 1974, who lived in the same region half a million years later.

The paleontological reconstructions of the deposits in Kanapoi, where Australopithecus anamensis emerged  , are very similar to those of Australopithecus afarensis  but occupying different settings: it inhabited open wooded spaces and also areas with thicker vegetation.

As we pointed out previously, its bipedal ability (but without ceasing to have climbing skills) allowed it to move over land in the African savannas and also to take refuge in trees and vegetation if necessary.

The research assessed the microstriation pattern of all Australopithecus anamensis specimens recovered until 2003, of which only five show a good state of preservation.

The results reveal that the diet of Australopithecus anamensis was similar to that of other current primates, such as baboons and the green monkey, which live in savannas with marked climatic seasons.

Tools

At first it was believed that the genus Homo had produced the first tools and utensils; However, more recent findings dating from the time Australopithecus existed suggest that they already had certain types of tools with which they cut the skin and bone of the product of their hunt.

The cuts that show bones dated in more than three million years could not be made except with at least stones sharpened for that purpose, trying to extract the marrow from them. This gives Australopithecus the ability to produce sharp objects, although quite archaic.

By practicing carrion, it was able to throw stones as tools to scare off predators and take advantage of the remains of its prey. Not having the management of fire, he consumed raw meat.

Activities

Nomadic in nature, Australopithecus anamensis moved along the savannahs surrounding the Serengetti, using its walking and climbing abilities. As for his locomotion, it is estimated that he walked on two legs.

The upper end of the tibia that joins the knee and the connection with the ankle is very similar to that of modern humans, indicating the ability to support the weight of the body on a single leg to walk upright on a regular basis.

The fossil of the same Australopithecus anamensis tibia shows a concave upper end, which indicates that there was considerable friction between both bones, such as that achieved with daily bipedal movement.

The thicker and wider ankle joint — adapted to absorb the shock of a bipedal movement — suggests that it was the usual and perhaps preferred way to move.

Wooded context

The environment in which Australopithecus anamensis lived must have been forested, in large areas full of plant life, which occurred near lakes. As mentioned above, the name of the species is derived from this: the word anam means “lake” in the Turkic language, which is typical of Kenya.

The work carried out by various teams of researchers for more than 50 years has served to shape all these fossils of great antiquity and that have formed a species that complements the links in the evolutionary chain that leads to Homo sapiens .

To this day, research continues to corroborate that this Australopithecus species really deserves to be separated from afarensis and if its previous evolutionary advance was represented by Ardipithecus ramidus .

Latest find

In December 2005, the team of Tim White, a paleoanthropologist and professor at the University of Berkeley in California, found remains of this species at the Asa Issie site, northeast Ethiopia, in the Awash Valley.

White and his team found a femur, some jaw fragments and teeth, including the largest canine found among hominids. All these elements were essential to complement the classification of the species.

References

  1. “They rebuild the diet of Australopithecus anamensis” (July 10, 2012) Agencia SINC. Retrieved on September 7, 2018 from: Agenciainc.es
  2. “Australopithecus anamensis: coming down from the trees”. Patri Tezanos in Antroporama. Retrieved on September 7, 2018 from: antroporama.com
  3. “Hominids used tools and ate meat much earlier than expected.” London Agency, BBC Mundo. Retrieved on September 7, 2018 from: bbc.com
  4. “Australopithecus already used tools 3 million years ago” (April 11, 2016) Chronicle. Recovered from cronica.mx on September 7 from: cronica.com.mx
  5. «What does it mean to be human? Autralopithecus anamensis »(24 August 2018) Smithsonian National Museum of Natural History. Retrieved on September 7 from: humanorigins.si.edu
  6. “Tim D. White American paleoanthropologist”. Mary Jane Friedrich (Aug 20, 2018) Encyclopedia Britannica. Retrieved on September 7 from: britannica.com

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