Respiratory Conchae

["Steve Brusatte" <dinoland@lycos.com>]

Hey,
Okay, here's my taken on Ruben et al.'s RT study.

Frankly, I think that, athough it has a basis, his study leaves out a lot of 
evidence.  I do respect Ruben's research, but he does leave out a lot, much of 
which is mentioned in HP Guy Leahy's Scientific American Book of Dinosaurs 
chapter, as a previous list member mentioned.

Leahy writes that structures that appeared to support respiratory conchae have 
been found in ceratopsids and anklyosaurs, both Cretaceous lineages.  I have 
read some of the previous posts on this list, mostly by our new member, which 
have discussed RTs and their role in extinction.  If RTs did play any role in 
extinction, ceratopsids may be the place to look...

Also, Leahy writes in his chapter, that some sauropods, hadrosaurs, and other 
herbivorous dinosaurs were found to have large enough nasal passages to possess 
these RTs.  Furthermore, he writes, that some birds possess very small nasal 
chambers, and still do possess conchae.

Of course, these arguments are all very good ones, but the most important issue 
that we should all remember is that RTs are CARTILAGE in birds, and likely were 
composed of cartilage in dinosaurs, too (in mammals they are often bone...look 
in the skull of a deer or wolf to see the numerous thin sheets of bone).  
Except in rare places, cartilage does not fossilize very well, and, therefore, 
finding direct evidence of these RTs is difficult at best.  More attention 
should be given to muscle attachment sites and nasal sizes.  Even then, though, 
nobody is quite sure exactly if RTs are that important in dinosaur research.  
As one list member posted earlier today, 'nobody cares by Ruben.'  This isn't 
necessarily true, but close...

Steve

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Steve Brusatte-DINO LAND PALEONTOLOGY
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