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

["T. Michael Keesey" <keesey@gmail.com>]

On Mon, Nov 17, 2008 at 11:59 AM, David Peters <davidpeters@att.net> wrote:
>
> Yes and perhaps not, IMHO. The transition from dinos to birds

I assume you mean the origin of avialans (flying coelurosaurs) here.

> happened in
> China. The transition from longtailed to shorttailed pterosaurs happened in
> Solnhofen -- unless the transitions were happening worldwide and only
> preserved at these two locations. Seems doubtful considering present day
> analogs.

A) But why would you assume present-day geography?
B) What transitions are going on today that are analogous to the
origin of avialans? I can't think of a single one.
C) What transitions are going on today that are analogous to the
origin of pterodactyloids? And since this is a clade within a flying
clade, why couldn't it have wide geographical distribution?
D) The origin of pterodactyloids had already taken place by the time
the Solnhofen deposits were created, so it clearly did not happen at
that time.

> Still the timing is right. Not sure about the Chinese geography,
> 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.

Changes can occur anywhere -- look at our own species.

-- 
T. Michael Keesey
Technical Consultant and Developer, Internet Technologies
Glendale, California