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Re: New findings Support Spinosaurus Sail as thermal regulator (My own theory)



In living sailfish, from what little I have read on the subject, the sail may 
serve multiple functions, from sexual signaling and (possibly) thermoregulation 
to herding prey. The same could have been true in sail-bearing tetrapods - 
there is no reason to suppose that there is only one "right" explanation for 
their sails (any more than there is for bird wings), and the proximate cause of 
their evolution could have shifted as they grew larger. 

Ronald Orenstein 
1825 Shady Creek Court
Mississauga, ON
Canada L5L 3W2
ronorenstein.blogspot.com

> On Sep 15, 2014, at 7:05 AM, Dann Pigdon <dannj@alphalink.com.au> wrote:
> 
> 
>> On Sun, Sep 14th, 2014 at 12:14 PM, Vlad Petnicki 
>> <bucketfoot-al@justice.com> wrote:
>> 
>> I'll throw something out to the professional scientists out there that 
>> dawned on me today:
>> 
>> The sail could not only have been added ballast, it may indeed have served a 
>> heat regulatory
>> purpose. I think this is doubly likely since the new findings establish that 
>> it was skin covered
>> rather than a hump - the easier to warm the blood that courses through the 
>> vessels just under the
>> skin.
>> 
>> Think about this: Crocs need to get out of the water to sun themselves (yes, 
>> I KNOW that
>> Spinosaurus was most likely NOT (as) cold-blooded as Crocs are), but 
>> regardless of how
>> "warm-blooded" it was, if the water ever got too cold, the swimming/wading 
>> Spinosaurus could
> just
>> turn the sail towards the sun - and voila - thermal regulation that does not 
>> require it to leave
>> the water.
> 
> The problem with thermoregulatory explanations for dorsal sails is that often 
> there were closely 
> related species living in the same part of the world at the same time that 
> lacked them completely. 
> Large dorsal sails tend to be extremely rare amongst dinosaurs in general, 
> and when they do occur 
> it's usually in a species that is far from representative of their particular 
> group (Ouranosaurus, 
> Armargasaurus, Spinosaurus, etc).
> 
> The various sizes and shapes of dorsal sails amongst the spinosauridae might 
> suggest that species 
> recognition was their main purpose. Spending a lot of time wading in deep 
> water might have 
> obscured other clues, such as differences in colouration or bodily 
> proportions. Dorsal sails of 
> different sizes and shapes (and perhaps colours) that stuck out of the water 
> might have helped to 
> advertise what species animals belonged to, allowing them to easily tell a 
> potental ally (or mate) 
> from a competitor.
> 
> -- 
> _____________________________________________________________
> 
> Dann Pigdon
> Spatial Data Analyst               Australian Dinosaurs
> Melbourne, Australia               http://home.alphalink.com.au/~dannj
> _____________________________________________________________
>