Re: egg development and O-2

[David Marjanovic <david.marjanovic@gmx.at>]

> Test:
> Has anyone compared the pore diameters of fossil hard-shell archosaur
> eggs (pick a group) over geologic time?

Probably not, but it should be easy to do... except perhaps for the fact 
that known fossil eggs are very unevenly distributed over time...

> There must have been at least a few taxa around at the Permian-Triassic
> boundary that layed hard-shelled eggs.

Why? The archosaur crown-group is surely younger than that; so are the 
geckos and so are the few turtles that lay hard-shelled eggs.