Re: Are dinosaurs really reptiles?

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

> That would indeed be an excellent name for the sauropsid crown group!

Perhaps it should be reserved for something apomorphy-based, though, because 
many early amniotes are preserved in materials that might occasionally 
preserve skin impressions (and regularly preserve the relief of ossified 
dermal, as opposed to epidermal, scales). It's not like the amnion, where 
the probability of fossilization is completely negligible. Scales of 
Cretaceous squamates are regularly preserved in KonservatlagerstÃtten, and 
there's a Middle Triassic *Macrocnemus* with scales; the JVP of December has 
a paper on a *Leptorophus* specimen (called *Melanerpeton*, which nobody 
else seems to do; may or may not make sense) that preserves the pigment 
pattern of the skin -- and that's around the Carboniferous-Permian boundary.

And then, how old exactly are mammalian tail scales? Monotremes lack them, 
but is that just because there are no mouse-sized monotremes with long tails 
(anymore)?