Lucy was not alone. Scientists have unearthed fossilized bones that they believe must have belonged to the foot of another pre-human species that walked upright around 3 million years ago, the AP reports. It's the first evidence of such a species during that era since the one made famous by the Lucy skeleton. This foot clearly comes from a different species, but like Lucy its foot was designed to both walk and grab tree branches, with an opposable toe.
The bones were discovered in Ethiopia, and dated to 3.4 million years ago, according to the BBC. For now, scientists can't classify the creature further, because they haven’t found its skull. "We've kept digging," says the curator of the Cleveland Museum of Natural History. "We have a few isolated teeth, but that's all." Still, even this limited find "is really exciting," one London palaeoanthropologist says. "This new foot helps elucidate the process of how the bi-pedal foot evolved." (Read more Lucy stories.)