Two-million-year-old Australopithecus sediba's awkward strut would eventually send a modern man begging for a knee or hip replacement, but scientists are stunned at how evolution equipped her for both climbing trees and walking.

The latest research on an unprecedented set of fossil bones from South Africa reveal an ancient creature with long arms and primitive shoulders like an ape, but legs that could straighten, dexterous hands and a human-like thumb for precision grip.

'Just a weird, weird combination,' said Jeremy DeSilva of Boston University, lead author of one of the six articles in the US journal Science that describe the most complete set of bones ever found for an early hominid.

The latest findings offer more distinctions from the famed hominid Lucy, who was discovered in 1974 and whose species Australopithecus afarensis roamed eastern Africa 3.2 million years ago, experts said.

'What these papers suggest is that sediba probably doesn't come from the East African species that Lucy comes from,' said Lee Berger, who in 2008 discovered the fossil site of Malapa, north of Johannesburg, where excavations are ongoing.