Posted: Nov 26, 2019 12:36 am
Which looks extremely fishy to me, I suspect that small holes in 3-million-year-old fossils may not be exactly the size they were in life?
Well, those holes didn't get smaller after the organism died.
This point is well away from the regression line: if correct, the claim is that australopithecines had a very noticeably lower blood flow to the brain than would be expected for haplorhines in general, and great apes in particular.
That is indeed the claim (well, not the bit about haplorhines in general, as I don't know how you arrived at that), but it's also a fact insomuch as australopithecines must have had a noticeably lower level of blood flow to the brain as seen by the relative size of their arterial foramina.
I think the point you're missing, however, is the 3 million year gap, and consequent morphological evolution, between all these modern species and australopithecines.