@Aedes,
... just saw the Discovery Channel's report on this:
Discovering Ardi. There's also a ton of information on the web - just released after almost 20 years of analysis.
I was highly encouraged and fascinated with the wealth of information this find brought. 4.4M Years old, pelvis clearly shows this one walked upright; and did so in a terrain (now Ethiopia) that was vastly different. She had opposing thumbs (including still the feet) yet still a much smaller brain. Apparently, this specimen falls in the human-line (not the "Y" in the road) but its age suggests that the the simian/human breakpoint is much older than thought previously. If true, the chimps we see today aren't what we evolved from; moreso, what we have today are the distant descendants of our common creature.
In any case,. it brought up many more questions, but still is an exciting piece of the puzzle.