[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: respiratory turbinates



In message <199609111623.LAA17785@juliet.ucs.indiana.edu>,
nking.ucs@smtp.usi.edu writes

>This information may be from an article published in Science (v. 273, 30 
>August, 1996, p. 1204-1207), by J. A. Ruben, W. J. Hillenius, N. R. 
>Geist, A. Leitch, T. D. Jones, P. J. Curie, J. R. Horner, and G. Espe 
>III, entitled The Metabolic Status of Some Late Cretaceous Dinosaurs.
>
>They examined the nasal regions of Nanotyrannus, Ornithomimus, 
>Dromaeosaurus, and Hypacrosaurus, looking for evidence of, or room for, 
>respiratory turbinates, as are found in more than 99% of living birds and 
>mammals.  They concluded that the dinosaurs examined did not have room 
>for such structures [...]

>The authors suggested that presence or absence of respiratory turbinates 
>may be used to assess the metabolic status of extinct vertebrates.  
>Respiratory turbinates and otherwise enlarged nasal passages are believed 
>to be associated with elevated lung ventilation rates, and, by extension, 
>with high routine metabolic rates.  

I'm fine so far, I merely note that association does not imply
causation...

>Their absence implies that metabolic and lung ventilation rates were
>sufficiently low that evaporative water and heat loss was not a
>problem.

And I can imagine that turbinates might increase evaporative area and
therefore heat loss.  But I can't make out how they would help to
conserve water.  Or am I misunderstanding the above, and also Fastovsky
and Weishampel's little textbook which seems to say the same thing?  

I guess that any hypotheses about other dinosaurian ways of getting rid
of heat must remain untestable speculation?  Or can anybody make a
suggestion?

Dr Richard Keatinge, 
fan of fast dinosaurs

http://www.ihi.aber.ac.uk/Other/maternity.html
am fanylion gofal mamolaeth gorau yng Nghymru / for details of best maternity
care in Wales