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.
There have been a couple of hominid bones found that are even older than Ardipithecus, but none with enough fossils to even begin reconstructing a skeleton. Link -via Metafilter