Ardi's femur and pelvis offered a close look at the stride of Ardipithecus ramidus, and it again came as a surprise. Although Ardi worked with a more primitive bipedal gait than her supposed ancestor Australopithecus, when on the ground she stood upright and was bipedal, at least when standing on the ground, in contrast to extant African apes. Ardi could still move about in trees, as evidenced by powerful hindlimb muscles, but by 4.4 million years ago, our ancestors were already well-established walkers.
Sources
Lovejoy, C. O., et al. 2009 The Pelvis and Femur of Ardipithecus ramidus: The Emergence of Upright Walking. Science 326:71e1-71e6.
- Ardipithecus ramidus, the blog post, which has links to recent news stories
- Lucy, famous Australopithecus afarensis
- Hominin
- Aramis, Ethiopia
- Bipedal locomotion
- Middle Awash
