I heard they found another skull with the same size. Some argued that it was statistically improbably to have two microcephalic individuals in the same area. I suppose one argument could be that the type of microcephaly these individuals had was genetic and possibly hereditary (proof of evolution?). Another argument could be that the microcephaly was rare and scattered in time and space but that the normal humans gathered them together in that location (in space, if not time) for some reason.