Peter,
Quantified data is still data none the less, here say and such is just that, there are no peer reviews on internet sites including things like wikipedia etc, and certainly the data I presented above is what I have found to be relatively consistant, however the are always exceptions and the more specimens you examine the more robust the data set is and therefore the general accuracy of the overall picture. However While I do not expect anyone to listen to what i say or type (on face value alone) I would not state it, if it was not what my data had found.
I think that if people on a reptile site (regardless of which one) had to use their real names as opposed to hiding behind synonyms (I am not saying that you are doing this) then you would find a sharp drop in the amount of bull waste that seems to accumulate on forums. As people would be accountable for what they say. Sure post counts would drop, but so would the amount of waste to wade through.
I digress, ON Pseudechis porphyriacus, head width v body size I assume you are talking about Rick Shine's paper of evolution of P.p adapting their head to suit Rhinella?
I need to re read it (I have not read it recently) but I thought it would difficult to link head size shifts with the length of time that Rhinella has been in Australia, I mean if you look at the Rhinella release site and date (Gordonvale, Nov,1935 ) its only 83.5 years.
As the bufotoxin is very lethal (to most Australian snakes, Keelback are a recent invader from indonesia most likely 50,000 years ago and have evolved alongside native bufonids) and as snakes higher vertebrates I would think it would take quite awhile for a species to adapt/evolve to be able to survive with a reasonable ingestion on the toxin.
So to accept Shine's finding that toads have caused the significant evolution (head shape shift) of a higher vertebrate in as little as 27 odd generations I find possibly flawed. A possible answer could be that not all P.p pops are generalists but some are specialists (possibly mammal or squamate predators as opposed to anurans) and prior shifts within these populations have not only adapted their diet preferences but also their head shape.
Cheers,
Scott Eipper