Re: taxonomy is not stratigraphy (was Re: JVP 25(2): New Dinos, Birds, Discoveries)

[Tim Williams <twilliams_alpha@hotmail.com>]

Tim Donovan wrote:

> > Agreed.  Unless the adult titanosaur was wounded or sick.
>
> P. Currie mentioned healed bite marks on sauropod bone from the Morrison, 
> IIRC, suggesting that even early theropods attacked sauropods capable of 
> defending themselves.

Well, I'm not suggesing that the predator had a 100% success rate.  Even 
weak and sick prey manage to escape sometimes.

>  Giganotosaurus and Argentinosaurus,
> Carcharodontosaurus and Paralititan,
> Torvosaurus/Epanterias and Brachiosaurus etc. Starkov mentioned other 
> examples.

This reprises some of what Denver said: just because a given habitat 
includes both a very lage predator and a very large herbivore does not 
necessarily means that the former specifically targeted the latter.  
Medium-sized predators may have sought prey larger or close to the size of 
themselves (e.g., _Velociraptor_ vs _Protoceratops_; _Deinonychus_ vs 
_Tenontosaurus_, maybe).  Large predators may have sought prey much smaller 
than themselves.  There is a chapter in the new _Carnivorous Dinosaurs_ 
volume dedicated to this issue.  I think Starkov's one-on-one predator-prey 
match-ups are too simplistic.

>  Yes, but Tarbosaurus was smaller than T. rex,

Not by much (if at all).

> Based on that, and the Tyrannosaurus-like TMM 41436-1 in a titanosaur 
> dominated mid Maastrichtian environment, it appears that Starkov is right 
> about the origin of T. rex. Like
> previous theropod giants, it apparently arose in response to large 
> sauropods.

Or vice versa.

Cheers

Tim