Bipedal Locomotion in Early Hominids Until recently, the oldest fossil species to provide evidence for bipedalism was Australopithecus afarensis, of which the best example of is the 3.2 million year old skeleton called Lucy found in Hadar, Ethiopia. According to article 19: Sunset at the Savanna, in 1995 Meave Leakey of the national Museums of Kenya and her colleagues made public the discovery of and older hominid species Australopithecus anamensis (getting its name from the Turkana word for lake “anam” having been found near lake Turkana and the site of another ancient lake). Leakey’s team found a tibia from this creature that is quite human like and emphatically bipedal, “in size and practically all details of the knee and ankle joints… (it) resembles the one from the fully bipedal A. afarensis”. The site where the fossils were found was dated to 4.2-3.9 million years ago; making 4.2mya the oldest date at which we can say that bipedalism has been proven to have emerged. There are also many other more recent fossils which have evidenceof bipedalism: Australopithecus africanus, Australopithecus robustus, and maybe another recently found fossil classified Ardipithecus ramidusThere are several aspects of skeletal anatomy that indicate bipedalism. We learned in lab last week that the pelvis has features that indicate the mode of locomotion. A bipedal creature will have an ilium that is short and wide. The leg bones will give clues too. A bipedal creature has knees that point more directly forward than a quadrapedal creature (this is why apes look very awkward when they walk bipedally, their legs kick out to the side when they step forward.) Another skeletal feature that indicates bipedalism is a special design of the anklebones so that they would be able to take the weight of a bipedal stride. The knee bone of a bipedal hominid has a special feature too. It has extra spongy bone tissue that...
