Re: What the fossil record tells us about trends in pterosaur diversity

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

----- Original Message ----- 
From: "David Peters" <davidpeters@att.net>
Sent: Monday, November 17, 2008 8:59 PM

> Yes and perhaps not, IMHO. The transition from dinos to birds
> happened in China.

What? Where do you get that idea from? We have *Archaeopteryx* in the 
Tithonian, very similar teeth in the Kimmeridgian, "dromaeosaurine" teeth 
also in the Kimmeridgian, an unnamed troodontid (apparently in addition to 
*Koparion*) in the Morrison Fm and thus perhaps as old as Oxfordian, and so 
on!

> The transition from longtailed to shorttailed
> pterosaurs happened in Solnhofen --

What do you think about *Herbstosaurus*?

Also, if you really mean "short-tailed pterosaurs" rather than 
"pterodactyloids", we have *Batrachognathus* which is at least as old as 
*Anurognathus*, and *Jeholopterus* which might be even older (though it's 
probably quite a bit younger).

> unless the transitions were
> happening worldwide and only preserved at these two locations.

Or unless they had happened long before and simply didn't leave any fossils 
in the places where we've been looking.

Which returns us to the very point of Butler et al.: The pterosaur fossil 
record so strongly reflects taphonomic and similar biases that it cannot 
tell you anything about pterosaur evolution, diversity or extinction (unless 
you use an extremely coarse scale). Throughout this e-mail, you try to take 
the fossil record literally. Butler et al. have demonstrated that you 
shouldn't.

> Seems doubtful considering present day analogs.

Like what?

> Still the timing is right.

Why?

> Not sure about the Chinese geography,

A couple lakes in a forest. Much like Messel 70 million years later.

> but as I recall, the Solnhofen
> geography was made up of isolated islands with lots of beach front
> property. Sort of like the Galapagos, only on a larger scale? Prime
> real estate for changes to occur.

That does not follow.

> So, do certain niches with variable landscape and weather seem to 
> accelerate change?

What makes you think the plated-limestone basin had variable weather?

I don't think any halfway quantitative research has been done on directional 
vs stabilizing selection in different environments.

> And do such landscapes create Lagerst[ä]tte[n]?

The Galápagos obviously don't... they are eroding volcanic islands 
surrounded by deep ocean...