Re: On rearing in sauropods

[Heinrich Mallison <heinrich.mallison@mfn-berlin.de>]

Waylon Rowley schrieb:
> > A sauropod neck leaves ample room for such 'second heart' cavities, 
> and arterial walls
> > are muscular anyways. Evidence? None, sadly!
>
> Since you're speculating, what about this:
>
> Not only are there 'auxilliary hearts', but also lungs. The pneumatic 
> spaces in the cervical vertebrae are covered in respiratory epithelia, 
> with a rich supply of arterial and veinous blood running through it, 
> like a simple lung (lungfish-like), but unpowered. So, as deoxygenated 
> blood flows away from the brain, it gets reoxygenated (partly) in the 
> neck, then shunted into the arterial vessels leading back up to the 
> brain....it doesn't need to travel up the entire neck, reducing 
> pressure demands on the heart. Maybe sauropods could temporarily 
> created a closed loop high up on the head and neck, allowing them to 
> raise the neck suddenly. Thoughts?
This idea - neck = second lung - did indeed crop up in several debates 
in Bonn. However, we are totally unsure about how much these air sacs 
were ventilated, leaving the oxygen content in them open for discussion. 
An interesting model, in any case :)

--
Dr. Heinrich Mallison
Museum fÃr Naturkunde - Leibniz-Institut fÃr Evolutions- und
BiodiversitÃtsforschung an der Humboldt-UniversitÃt zu Berlin
Invalidenstrasse 43
10115 Berlin


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Email: heinrich.mallison@mfn-berlin.de