Australopithecines afarensis is the oldest of four species of australopithecines, an extinct genus of the hominid family found in E and S Africa between 4 and 1 million years ago dating, which is know to be at least 3.75 million years ago. Evidence from 3.6 million-year-old footprints, preserved in volcanic ash at Laetoli, and from postcranial skeletal remains show that Australopithecines afarensis was relatively small, standing 3.5 to 5 ft (1 to 1.6 m) tall and weighing 45 to 110 lb (20 to 50 kg). All four species shared a number of anatomical similarities, including a fully erect posture and bipedal gait. The most "primitive" feature was a small and apelike braincase, comparable in size to those of both gorillas and chimpanzees when measured relative to overall body size.