he discovery of this hominin was significant as the skeleton shows evidence of small skull capacity akin to that of apes and of bipedal upright walk akin to that of humans, providing further evidence supporting the view that bipedalism preceded increase in brain size in human evolution ...

And the lesser known Ardi:

A. ramidus feet are better suited for walking ...

Researchers infer from the form of Ardi's pelvis and limbs and the presence of her opposable big toe that she was a facultative biped: bipedal when moving on the ground, but quadrupedal when moving about in tree branches. Ardi had a more primitive walking ability than later hominids, and could not walk or run for long distances.

Goes to show bipedalism arose before the increase in brain size.  

Ardi is even more interesting due to:

The canine teeth of A. ramidus are smaller, and equal in size between males and females. This suggests reduced male-to-male conflict, pair-bonding, and increased parental investment. "Thus, fundamental reproductive and social behavioral changes probably occurred in hominids long before they had enlarged brains and began to use stone tools"

Implying modern human-like in-group socialization and conflict resolution, and the relatively well developed pre-frontal cortex required for such, arose first ... even before 100% bipedalism and tool use.  

Ever since I learnt about confirmation bias I've started seeing it everywhere