In a discovery sure to fuel an old debate about our evolutionary history, scientists have found a remarkably complete skeleton of a 3-year-old female from the ape-man species represented by "Lucy."

The remains found in Africa are 3.3 million years old, making this the oldest known skeleton of such a youthful human ancestor.

"It's a pretty unbelievable discovery... It's sensational," said Will Harcourt-Smith, a researcher at the American Museum of Natural History in New York who wasn't involved in the find. "It provides you with a wealth of information."

For one thing, it gives new evidence for a contentious feud about whether this species, which walked upright, also climbed and moved through trees easily.