By Maina Kiarie
Australopithecus anamensis lived about 4.2 to 3.9 million years ago around Lake Turkana in Kenya and the Middle Awash region Ethiopia. Discoveries in 1994 by a research team led by paleoanthropologist Meave Leakey found numerous teeth and fragments of bone at Kanapoi in Northern Kenya at the same site where in 1965 a team from Harvard University led by Bryan Patterson had found an arm bone whose species they were unable to identify. Leakey and her colleagues determined that the fossils were those of a very primitive hominin and they named a new species called Australopithecus anamensis (‘anam’ means ‘lake’ in the Turkana lanaguage). Researchers have since found other Ausstralopithecus anamensis fossils at nearby sites (including Allia Bay), all of which date between about 4.2 million and 3.9 million years old.
Analysis of the upper end of the tibia (shin bone) showed an expanded area of bone and the orientation of the ankle joint resembling that of a human. This indicated Au. anamensis regularly walked on two legs. Long forearms and features of the wrist bones suggest these individuals probably climbed trees as well.
The species was possibly the size of a female chimpanzee and there is evidence showing that there was a difference in the size of males and females (a feature known as sexual dimorphism). They had thickly-built, long, narrow jaws with their side rows of teeth arranged in parallel lines. These strong jaws with heavily enameled teeth suggest the species may have eaten hard, abrasive foods and were generally plant eaters, relying on both fruits and tough foods such as nuts. The sites where the species have been found were forests and woodlands that grew around lakes.