Re: Fw: late night thoughts: misunderstand what?

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

> I think we are assuming different margins of error. My assumptions are 
> quite large. It boils down to the probability of a given individual 
> organism being both preserved and found, something that varies according 
> to lifestyle and environment. I think that combined probability for 
> terrestrial vertebrates is very, very, very low. Finding one individual in 
> a given location indicates a long presence on the planet and says little 
> about real geographical distribution.

Are you saying your hypothesis is not testable?

I hope you aren't.

> Our perspective on evolution is evidently very different. I don't think 
> that the end theropod being the biggest, and the end sauropod being the 
> most armored, and quite large, does anything to falsify the notion of a 
> prey/predator size race.

But that's not the case. Armor has AFAIK not been found on anything bigger 
than *Isisaurus*, which was bigger than *Opisthocoelicaudia*, 
*Nemegtosaurus*, *Quaesitosaurus*, and at least most of *Alamosaurus*. 
Furthermore, it lived in India in the absence of any known extra-large 
theropods, and it's rather average for Jurassic sauropod measures. 
*Puertasaurus* is huge, but again lacks known extra-large theropods in its 
environment.

And then there's, again, the fact that neither minimum nor maximum nor 
average sauropod (or even sauropodomorph) size increased across the 
Mesozoic. Your hypothesis says they did grow bigger, the fossil record says 
they didn't, your hypothesis loses. Am I missing something?

> From what you (and others) say, that was the situation. That T.rex evolved 
> separately from the allosaurids seems indicative to me that the 
> evolutionary sub-strate was conducive to creating mega-predators.

Interesting, then, that there's no or almost no size increase in allosaurids 
from the Late Jurassic (*Saurophaganax*) to the beginning of the Late 
Cretaceous (*Carcharodontosaurus*, *Giganotosaurus*); and AFAIK the one or 
two later known allosaurids were smaller again.

> Why would I conclude that sauropods weren't a part of that?

Because they exhibit a complete lack of any trend towards increasing body 
size.

> Where's the beef?

The slaying of a beautiful hypothesis by an ugly fact.