摘要：StW573, or ‘Little Foot’, is a nearly complete Australopithecus skeleton discovered in 1997 1 , in Member 2 of theSterkfontein Formation – the oldest fossil-bearing member of the cave 2 . The importance of StW573 lies not onlyin its completeness, which provides comprehensive anatomical and locomotor information on one individual, butalso in its age and phylogenetic relationships with other hominid species. The age of StW573 was first suggestedto be about 3.5 Ma based on its deep stratigraphic position and the absence of any other hominid fossils whichare so abundant in the higher Member 4 deposits. 3 McKee 4 argued on faunal grounds that it should be younger,but Tobias and Clarke 5 countered his arguments. Berger et al. 6 even suggested that StW573 ‘may be as young as1.07–1.95 Ma’. Their arguments were comprehensively countered by Clarke 7 . A date of 4.17±0.35 Ma was basedon cosmogenic burial dating of the breccia in which the skeleton was found. 8 Dating has also been applied to calcitespeleothems found in close proximity to the skeleton 9-12 , but careful stratigraphic mapping 13 refined and expandedin Bruxelles et al. 14 shows that the speleothems postdate the skeleton and thus cannot be used to determine morethan a minimum age for the specimen.
