Top questions
What does anamensis mean?
It comes from 'anam', the word for lake in the Turkana language of northern Kenya. The species was named in 1995 for the Lake Turkana basin, where the first fossils were found.
Did Australopithecus anamensis walk upright?
Yes. A shin bone (tibia) from Kanapoi in Kenya, about 4.1 million years old, has the shape of a bone that carried the body's weight on one leg at a time, which is the mark of walking on two legs. It also had features for climbing, like its descendants.
Is anamensis the ancestor of Lucy's species?
Probably, though not for certain. Anamensis fits the shape of an older version of Australopithecus afarensis and lived just before it in the same area. But a skull found in 2016 and described in 2019 shows the two species overlapped in time, so one did not simply turn into the other.
Who found the first anamensis fossil?
A Harvard team led by Bryan Patterson found a piece of upper arm bone at Kanapoi, Kenya, in 1965. It was not recognised as a new species for 30 years. Meave Leakey's team named Australopithecus anamensis in 1995 after finding more fossils at Kanapoi and Allia Bay.
Was it bigger than Lucy?
Roughly the same, though estimates vary. Males may have stood about 1.3 to 1.5 metres and weighed up to about 50 kilograms, with females smaller.
The species in brief
Australopithecus anamensis is the oldest known member of the genus Australopithecus, and most researchers think it was the direct ancestor of the best-known species of the group, Australopithecus afarensis. It lived in the woodlands and bush of East Africa around the Turkana basin of Kenya and in the Afar and Woranso-Mille region of Ethiopia between about 4.2 and 3.8 million years ago.
The species is a bridge between the older, more apelike creatures such as Ardipithecus ramidus, and the upright-walking australopiths that followed. Its fossils are mostly teeth, jaws and limb bones. A good skull was not known until 2016.
Discovery
In 1965 Bryan Patterson, a Harvard paleontologist, found a fragment of an arm bone at Kanapoi, a dry, hot site southwest of Lake Turkana in Kenya. It was about four million years old, and Patterson thought it was probably an australopith, but little could be said with a single piece of bone.
Thirty years later Meave Leakey of the National Museums of Kenya and her colleagues returned to Kanapoi and to Allia Bay, on the east side of the lake. In 1994 and 1995 they found jaws, teeth, a shin bone and other bones, more than twenty fossils in all. They named the species Australopithecus anamensis in 1995, after the Turkana word anam, meaning lake.
The skull from Woranso-Mille
For decades anamensis was a species without a face. In 2016, an Afar herder named Ali Bereino told the team of the paleontologist Yohannes Haile-Selassie about a fossil he had seen at Woranso-Mille in the Afar region of Ethiopia. It was a skull lying in the surface soil. The team’s 2019 report described the skull, catalogued as MRD-VP-1/1, as nearly complete and about 3.8 million years old.
It showed a small braincase of around 365 cubic centimetres, a projecting face, a pronounced brow and a canine tooth that was bigger than expected. The face is more primitive than that of afarensis, with a long, apelike snout, but with some features that link it to later australopiths. Its age is important because it overlaps in time with the earliest afarensis, so anamensis did not simply change into afarensis and disappear. The two species lived side by side for perhaps 100,000 years, and afarensis may have split off from anamensis as a branch.
Body and lifestyle
- Walking. The Kanapoi shin bone, about 4.1 million years old, has a broad lower end and a shaft built to absorb the stress of a body’s weight carried on one leg at a time. It is among the earliest clear evidence for upright walking in the human family.
- Climbing. Features of the arm and wrist suggest anamensis could still climb well.
- Size. Estimates vary: perhaps 1.3 to 1.5 m (4 ft 3 in to 4 ft 11 in) tall for the larger individuals, with a body mass of up to about 50 kg. Males were larger than females.
- Teeth. Thick enamel on the cheek teeth and a large canine suggest a diet that included some tough food, and probably fruit and other plants.
- Habitat. At Kanapoi the animals found with it include browsing animals, and fossil plant remains point to wooded country close to a river, with grassland not far away.
Where it fits in the family tree
A growing set of fossils from Kenya and Ethiopia between 4.2 and 3.0 million years ago has led most researchers to think that anamensis gave rise to afarensis, which in turn probably led to later australopiths and, possibly, to the genus Homo. That straight-line model, called anagenesis, is now less certain, since the overlap seen in the Woranso-Mille skull shows a more branching pattern.
Where to see it
The Kanapoi and Allia Bay finds are held at the National Museum of Kenya in Nairobi. The Woranso-Mille skull is kept in the National Museum of Ethiopia in Addis Ababa. Lake Turkana, where it was first named, is described on the Koobi Fora page.
Sources
- Smithsonian National Museum of Natural History, Human Origins Program. Australopithecus anamensis.
- Leakey, M. G. and others (1995). New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya. Nature 376: 565 to 571.
- Ward, C. V., Leakey, M. G. and Walker, A. (2001). Morphology of Australopithecus anamensis from Kanapoi and Allia Bay, Kenya. Journal of Human Evolution 41: 255 to 368.
- Haile-Selassie, Y. and others (2019). A 3.8-million-year-old hominin cranium from Woranso-Mille, Ethiopia. Nature 573: 214 to 219.
Cite this page
Bonelore. "Australopithecus anamensis." https://bonelore.com/species/australopithecus-anamensis/