Re: Regarding Spinosaurus

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Fam Jansma" <fam.jansma@worldonline.nl>
Sent: Friday, January 11, 2002 5:21 PM


> >*Carcharodontosaurus* was full of air-sacs that even extended into its
> tail.
> >Maybe this is an answer (just speculating). *Paralititan*, as a
titanosaur,
> >should have been pretty hollow likewise.
>
> As far as I know of the remains known from Carcharodontosaurus are very
> fragmentary, but are caudal vertebrae known of it?

Sorry, actually I was talking about one of those unnamed
carcharodontosaurids from Argentina which has pneumatic vertebrae from the
neck to the base of the tail, a pneumatic furcula and pneumatic ilia, or so
they say in the SVP meeting abstract.

> >That are just three.
>
> [...] Nigersaurus,

No sail mentioned in the description.

> Suchomimus,

If you want to call that a sail... IMHO it's a bit small for that.

> Rayosaurus,

Are neural spines known of *Rayososaurus* (which some lump with
*Rebbachisaurus* and *Limaysaurus* anyway)?

> Amargasaurus

No longer interpreted as a double sail by most, but as a double row of
spikes.

> Spinosaurus sp. (the huge skulled Spinosaurus)

?

> I rest my case...

That went fast IMHO.

> >They are cold-blooded and spend most of their time lying around.
> >*Suchomimus* at least looks like having spended much of its time at least
> >standing, if not walking, and was pretty certainly warm-blooded.
>
> Without real evidence there is no way to be certain about the matter, it
has
> been proven that maniraptors are partly warm-blooded,

Why "partly"?

> it has been proven
> Ornithopods were probably warm-blooded,

Why in your opinion exactly ornithopods?

What about sauropods?

> but there is no evidence saying that
> Spinosaurs were warm-blooded.

They are theropods, and they are dinosaurs, and share an anatomy that points
at the capability for sustained activity (if only standing, but they must
have been able to run, or so I think when I look at any theropod leg).

> Alright, I know, opening old wounds here, but
> the sail could be evidence that is was col-blooded.

The only thing that sounded like positive evidence for any cold-blooded
dinosaurs was the respiratory turbinates thing, and even that has been
pretty much falsified.

> "Carnosaurs" (wrong
> term...) have a totally different physiology than the agile
"Coelurosaurus"
> by being more massive and all,

More massive? Hardly. At first glance all theropods are exactly the same,
the rest is details. Big theropods are just bigger and adjusted their
proportions accordingly (when a cylinder doubles in length it must multiply
its diameter by, erm, 3.2 or so [forgot the exact number] to resist the same
bending stresses). Many small theropods were far less pneumatic than the
above-mentioned carcharodontosaurid, BTW.

> so when saying if the Coelurosaurs were
> warmblooded, than Carnosaurs must be warmblooded is a wrong thought.

But saying that coelurosaurs, ornithischians, sauropods and, erm, all others
:-) were warm-blooded can be used to propose that dinosauromorphs only
evolved warm-bloodedness once, so why should any big theropods have lost
that?

(A posteriori, I define warm-blooded as I have used it here as endothermic +
tachymetabolic + tachyaerobic + homoeothermic... well, classically
warm-blooded.)