Re: question concerning respiratory turbinates

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

 

So if pterosaurs don't have RT's, then there's no conclusive way to say that dinsoaurs, because of a general lack of RT's, are not endothermic.

Yes. (Just that I don't know whether pterosaurs have RT's.)

Am I correct in assuming that RT's or a lack thereof, are non-evidence against endothermy in dinosaurs?

Probably. However, many dinosaurs have structures that probably served as RT's (think of the complicated bone sheets in ceratopsian noses), and often RT's are cartilaginous and won't fossilize. The famous CT scans of theropod skulls say nothing IMHO, because of crushing and poor resolution. BTW, elephants don't have RT's, and there are several other complicating factors that have often been reviewed onlist.

When you say that they are endothermic because of point #3, their fur, would that not, by the same reasoning, imply coelurosaurs are endothermic?

Of course, and vice versa. The air-sac system even implies that endothermy is a synapomorphy of Ornithodira or so (if it is monophyletic).