Re: Are dinosaurs really reptiles?

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

> 1) If we found vague impressions in a "stem-scutellate", could we
> really be sure they were homologous?

They wouldn't need to be vague. Or even to be impressions, as opposed to 
carbonized organic matter.

> 2) Just because it might be preserved doesn't mean that most fossils
> preserve it.

Of course most don't.

> 3) Isn't there some osteological character that suggests the presence
> of an amniotic sac in embryos? I can't quite recall what it is at the
> moment, but I'm sure I've heard of something along those lines.

I haven't. All I've read is that herbivory (as in diadectids) requires close 
association between hatchlings and adults and thus the amniotic egg so that 
the gut bacteria can be passed on, but that's simply wrong -- *Siren* is 
mostly herbivorous and even a hindgut fermenter, and that's an aquatic 
salamander that probably has external fertilization.

> 4) "Apo-Scutellata" would be available for the apomorphy-based clade, 
> anyway.

Yes, but this presupposes the Pan- "convention", which very few people have 
actually convened upon...