Lucy, you might remember lived about 3.2 million years ago, and was actually discovered about 46 miles from where "Ardi" was discovered.
The first seventeen fragments of an A. ramidus fossil were found in 1992-3 by a research team headed by Tim White. More fragments were found in 1994, making up 45% of the total skeleton. The fossil was originally labelled an Australopithecine, but White and his team soon renamed the genus "Ardipithecus".
Her feet are able to grasp things, much like a chimp's. However, she walked upright, and her teeth are closer to modern human teeth, and so are the teeth of the male ardipithecus, which I believe suggests an earlier move to peaceful domestic living than was previously believed.
Note that she is not a "missing link" between humans and chimps. Carl Zimmer: "Chimpanzees may be our closest living relatives, but that doesn’t mean that our common ancestor with them looked precisely like a chimp. In fact, a lot of what makes a chimpanzee a chimpanzee evolved after our two lineages split roughly 7 million years ago. Ardipithecus offers strong evidence for the newness of chimps."
Also Carl Zimmer:
"Men have stubby canines, which many scientists take as a sign that the competition between males became less intense in our hominid lineage. That was likely due to a shift in family life. Male chimpanzees compete with each other to mate with females, but they don’t help with the kids when they’re born. Humans form long-term bonds, with fathers helping mothers by, for example, getting more food for the kids to eat. There’s still male-male competition in our lineage, but it’s a lot less intense than in other species.
White and his colleagues found so many teeth of different Ardipithecus individuals that they could compare male and female canines with some confidence. The male teeth turn out to be surprisingly blunted. This result suggests that hominids shifted away from a typical ape social structure early in our ancestry. If this was a result of males forming long-term bonds with females and helping raise young, this shift was able to occur while hominids were still living a very ape-like life. Ardipithecus existed about 2 million years before the oldest evidence of stone tools, suggesting that technology was not the trigger for the evolution of nice hominid guys.""Six months ago, we would have said our common ancestor looked something like a chimp," said Tim White of the University of California at Berkeley, a senior researcher on the project. "Now all that has changed.
"What we found in Ethiopia at 4.4 million years ago is the closest we've ever come to that ancestor along our own line," White said.
Science Magazine has extensive articles on Ardipithecus, something like 15 years in the making.
Discover Magazine explains why this hominid is so significant.