The discovery of the distal end of this tibia (bone of the lower leg) of Australopithecus anamensis, meant that it was possible to determine that this species was indeed bipedal and therefore is classified as a hominin. It is still the most secure earliest evidence for bipedality, at 4.1 million years.A weight bearing bone has a distinctive morphology and if you study this distal tibia and compare it to the same bone in a primate that walks on four legs (such as a baboon or a chimpanzee) you can see that it is much more robustly built beneath the articular surface.
The proximal end of this bone was also recovered, however the middle section of the shaft was never recovered despite a large excavation.
Kanapoi is a site to the south west Lake Turkana, an area of undulating hills covered in basalt pebbles that cover the sedimentary deposits. The pebbles make it extremely difficult to spot any fossils on the surface.
