Both specimens of Australopithecus sediba recovered from Malapa Cave included partial pelves, allowing researchers to reconstruct a male and female pelvis and make comparisons between Au. sediba and other hominids. The pelves include both australopithecine and homo-like features.
According to the scholars researching Malapa Cave, the Au sediba pelvis seems to have already taken on some architectural features of modern humans, without a corresponding expansion in brain case size. Researchers have argued that the female pelvis widened expanded as a result of larger brain cases; in Au. sediba's case, the widening seems to have happened prior to the enlargement of the cranium.
Sources
Berger LR, De Ruiter DJ, Churchill SE, Schmid P, Carlson KJ, Dirks PHGM, and Kibii JM. 2010. Australopithecus sediba: A New Species of Homo-Like Australopith from South Africa. Science 238:195-204.
Kibii JM, Churchill SE, Schmid P, Carlson KJ, Reed ND, De Ruiter DJ, and Berger LR. 2011. A partial pelvis of Australopithecus sediba. Science 333:1407-1411.
