South African scientists claimed Thursday to have uncovered the most complete skeleton yet of an ancient relative of man, hidden in a rock excavated from an archaeological site three years ago. The remains of a juvenile hominid skeleton, of the newly identified Australopithecus sediba species, are the “most complete early human ancestor skeleton ever discovered,” according to Lee Berger of the University of Witwatersrand. The skeleton is thought to be around two million years old. “We have discovered parts of a jaw and critical aspects of the body including what appear to be a complete femur, ribs, vertebrae and other important limb elements, some never before seen in such completeness in the human fossil record,” said Professor Berger, who was involved in the finding. The latest discovery was made in a rock that lay unnoticed for years in a laboratory until a technician happened to see a tooth sticking out of the black stone last month. It was then scanned to reveal significant parts of A. sediba, whose other parts were discovered in 2009 in the world famous “Cradle of Humankind” north of Johannesburg. It is not certain whether the species, which had long arms, a small brain and a thumb, was a direct ancestor of humans’ genus, Homo, or simply a close relative.