The subheading says: A study of associations between stone tool evidence and fossil hominin remains shows that a wide range of species made stone artifacts. P

The subheading says: A study of associations between stone tool evidence and fossil hominin remains shows that a wide range of species made stone artifacts. Perhaps in the context of the field, the hypothesis is more clear. Also, does "study" refer to a particular published study that the author is reviewing, or to this blog post?