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Re: Concavenator has two humps



In fact, you drew a general conclusion (which, I'll give you that, you
qualified), despite there not being any strong indication that a sail
was present.

>>The arrangement tends to favor that
>>dinosaur sails were for display
>>rather than supporting fat deposits
>>in at least some cases.

(incidentally, I fully agree that the fat deposit hypothesis is unlikely.)

Additionally, you claimed

>>there are two humps

but the tail seems not to show a hump (up-down), but simply to have
(if anything) a long, high ridge.

Yes, the spines seem to get proportionally larger in front, so that
their top line may or may not have pointed at the top of the dorsal
spine - which would indicate a sail. But have you had the chance to
play with HR scans, to articulate them without hyperextension, so that
we can see if that's true?

How you jump to the conclusion that a muscle function is unlikely for
the tail spines is beyond me. Equally possible is that the animal had
an unusually muscular tail (note that I am not saying it is likely, we
just don't know). Let's wait for a detailed description of the spines,
their 3D morphology - if that is unusual (i.e., if they are not just
scaled-up), then we can assume that the forces acting on them were not
just scaled-up muscle forces, and then we can claim that a more
muscular tail is dubious.

by the way, you're allowed to talk/write to me directly, no need to
address me in the third person. I am not Caesar, and not infallible.

Best
HM


On Thu, Sep 9, 2010 at 5:32 AM,  <GSP1954@aol.com> wrote:
>
> In a message dated 9/8/10 8:01:04 PM, heinrich.mallison@googlemail.com
> writes:
>
> << I'd be very careful about jumping to conclusion about a "sail".  >>
>
> Heinrich should be very careful about actually reading what a message says,
> I never actually said that this specific theropod's tail had a sail in my
> previous message, I merely noted that the thesis that sails in general
> carried fat deposits is questionable. In any case the Concavenator tail base
> neural spines are much taller than normal in theropods so a muscle function is
> dubious.
>
> GSPaul
>
> </HTML>
>