Human Evolution VII: Australopithecus anamensis
Source: https://www.mchenry.edu/origins/species/australopithecus-anamensis.html
Around 4.3 million years ago, the oldest known Australopithecus, a name from the Latin and Ancient Greek meaning 'southern ape', arose around modern day Kenya in the Turkana Basin. The oldest known Astralopithecus was given the name A anamensis, from the Turkana word 'anam', which means 'lake'.
By Guérin Nicolas (messages) - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6516216
First discovered in 1965, a portion of a humerus, or upper arm bone, was found near West Lake Turkana was originally thought to be 2.5 million years old, and that was later adjusted to 4.5-4.0 million years old based on the other animals found around the fossil. In 1994, more fragments, including a complete lower jaw, was found near Allia Bay. The jaw has a structure that resembles modern chimpanzees, but its teeth have more in common with modern humans. Twenty-one fossils were found in total, including an upper jaw, parts of the cranium, and parts of both upper and lower leg bones. The second find was also about 9.7 km away from where Ardipithecus ramidus was found, a species that lived roughly 200,000 years earlier.
By Phil H. - Own work, CC BY-SA 3.0 de, https://commons.wikimedia.org/w/index.php?curid=31933854
During the time that A anamensis lived, the area around Allia Bay was fairly wooded with more savannas opening up around the edges of the basin and in the higher lands around it. The trees in the area were likely nut or seed-bearing trees but more research is needed to know for sure. Wear on the teeth found show that 'nuts, seeds, and hard fruit may have been an important component to the diet of this species', though they still ate significant portions of softer forest fruits. Examination of their tooth enamel also show that they largely ate food 'from trees and shrubs along with nongrassy forbs and herbs and their fruits' with some grasses or sedges with about 90% of their diet coming from the former, though they also might have eaten insects that ate the former as well.
By 宜蘭第一公民 - This file was derived from: Australopithecus afarensis Cleveland Museum.jpg, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=137846047
A anamensis appears to be a transitional species between Ar ramidus and A afarensis, having traits of humans and other apes. It seems to have used knuckle walking based on its long arms and robust phalanges and metacarpals though some researchers believe these characteristics show that A anamensis spent time living in trees but was largely bipedal.



















