 This angular joint was in contrast to an ape, which has the femur and tibia forming a straight line.Tom Gray walked up, and when shown the tibia on its own, thought it was a monkey, but when shown the angle formed with the tibia, agreed that this was from a hominid.This was an immensely important find, as it would be the first showing upright walking hominids from 3.4 million years ago.