Re: Pterosaur diversity (was: Re: Waimanu)

[Nick Pharris <npharris@umich.edu>]

Quoting Tim Williams <twilliams_alpha@hotmail.com>:

> > Ceratopsids, yes (probability of the increase I get being all random 
> > = 0.511 %, so the increase is highly significant... if it isn't an 
> > artefact of coding them all as either "Campanian" or 
> > "Maastrichtian", that is). But if I just add 5 more species to get 
> > Coronosauria complete (*Bagaceratops*, *Protoceratops* spp., 
> > *Leptoceratops*, *Montanoceratops*), the significance shrinks below 
> > what >is considered acceptable (it rises 26-fold to reach 13 %).
>
> OK, that surprises me.  I would have thought the effect of those 
> runty mid-Cretaceous psittacosaurs and "protoceratopsians", at one 
> end, and the ginormous Maastrichtian ceratopsids (like _Torosaurus_ 
> and _Triceratops_), at the other, would have given you a 
> statistically significant trend.  So much for my back-of-the-envelope 
> calculations!  There's that "psychological artifact" at work.

I suspect _Montanoceratops_, being small but late, may have much to do 
with this.

--
Nick Pharris
Department of Linguistics
University of Michigan

"Creativity is the sudden cessation of stupidity."
    --Edwin H. Land