Re: The New Paper That Time Forgot

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

> My question in regard to all of this is do we actually know that any 
> dinosaur had a cross-current unidirectional system in place? I can accept 
> that the most bird like dinosaurs (maniraptors, deinonychosaurs etc) 
> probably had the full suite of avian respiration in place, but I'm less 
> inclined to say the same thing for dinos further from the avian side of 
> the family.
>
> We have evidence of air sacs, but what evidence do we have for 
> unidirectional flow of air? Surely one likely came before the other. As 
> there are other animals today (certain snakes and insects) that have air 
> sacs, but no flow through system of gas exchange, I'm inclined to think 
> that air sacs came first; flow through second.

Sure, but what is the possession of both cervical and abdominal air sacs 
good for? And evidence for both is known from carnosaurs (most prominently 
*Aerosteon*) and sauropods.

> The authours [sic] argued that Lehman and Woodward had based their data 
> strictly off of long bone studies, but they didn't. Lehman and Woodward 
> used the exact same specimens that Erickson et al had used. Sander and 
> Clauss obviously had no problem with those specimens, as Erickson et al 
> was frequently cited, so I see no reason for them to complain about the 
> Lehman and Woodward study either.

OK, I'll read the paper. (I'm woefully behind on dinosaur literature.)

> The authours also stated that gastric mills were not present in sauropods. 
> Has that been confirmed now? Are sauropods officially considered not to 
> have gizzards anymore?

There was a paper on this topic a few months ago that got a lot of DML 
coverage, as I recall.