Re: The Permian-Triassic Extinction

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

> I'm not sure if I'm responding with another non sequitur, but with the
> continents jammed together to form one giant landmass (Pangaea), the
> terrestrial biotas were exposed to harsher, drier environments that 
> resulted
> from a drastic decrease in the ratio of coastline to the vast interior.

This would not mean an increase in global average temperatures, and that's 
what Dora seems to be saying.

> A sudden drop in global temperature followed by global warming
> is usually attributed to the Siberian Traps.

The drop would require sulfate aerosols, and these would require explosive 
volcanism -- that's the opposite of effusive volcanism which by definition 
must have produced the traps.

> The bolide hypothesis does not have much
> support when it comes to the Permian/Triassic extinction.

At least the supposed craters aren't published yet.

> No Permian dinosaurs (as others have pointed out, with admirable 
> restraint).
>  There were dinosaurian ancestors back then, in the form of basal
> archosauromorphs (and maybe archosauriforms).

Only one archosauriform -- the proterosuchid *Archosaurus rossicus* -- is 
known from the (very latest) Permian.