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Re: Tyrannotitan, new carcharodontosaurid from Argentina

>   Lions are vulnerable to hyenas and leopards, but
> remain key predators.

  I think you meant leopards are vulnerable to lions
but remain key predators.

> Spinosaurids are claimed to be vulnerable to carchs,
> but 1) *Spinosaurus*
> probably massed more than *Carcharodontosaurus,*
> which would have been slender,
> narrow and gracile, as in other allosauroids,
> whereas the
> "megalosaur/spinosaur" groups are distinctly robust
> and broad, and the ribcage
> in the Egyptian "fisheater" was extremely broad. 2)
> There is no such thing as a
> HUGE exclusive piscivore, and all large piscivores
> today (including whales,
> sharks and gharials, relative to their ecologies)
> take non-piscine prey
> frequyently enough to be considered opportunistic.
> 3) The snout of spinosaurs
> also appears to lack many piscivore traits including
> a rounded cross-section,
> but is mediolaterally narrow with deep roots,
> indicating a strong adaptation to
> vertical compressive forces, such that spinosaurs
> likely had a VERY powerful
> bite, as opposed to a weak bite in, say,
> *Allosaurus*.

  Why else would an elongated snout and jaws evolve?
If spinosaurs were more massive and powerful than
carcharodontosaurs, and piscivory seems questionable,
could they have been sauropod hunters, using their
long jaws to reach the necks of titanosaurs or
rebbachisaurs? Could their manual claws have been
offensive instead of defensive weapons, used to rip
open a sauropod's throat or sides?

> So, gives points 1, 2
> and 3, it is more likely that the jaw and body
> variation cleanly separated
> spinosaurs from carchs in both prey choices 

  The variety of suitable prey for giant predators in
the Baharije environment doesn't appear to have been
great. What else was there for a big predator besides
sauropods? Stomatosuchus? Ouranosaurus wasn't present
in that environmnt.

> ecology, and if anyhing, in a
> fight, I'd bet on spinosaurs to come out kicking and
> winning.

  Carcharodontosaurs are usually thought of as
sauropod hunters. If spinosaurs were more powerful,
maybe they took on the largest sauropods, like
Paralititan, and became extinct with such big prey by
the Turonian.

> <Lamanna mentioned a Campanian carcharodontosaurid
> and suggested that the
> Maastrichtian Abelisaurus might be one.>
>   Some ideas need to wait for publication before
> being used to counter
> arguments. We should use published, verifiable data
> first.
   That was from a JVP article. 


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