Complex sentence: Previously, evidence of stone tool use by "Australopithecus" has been suggested on the basis of marks on animal bones, but those findings have been hotly debated, with no scientific consensus forming on either side of the debate.
Split into simpler sentences: Previously, evidence of stone tool use by "Australopithecus" has been suggested on the basis of marks on animal bones. The findings have been hotly debated, with no scientific consensus forming on either side of the debate.