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Re: The birds vs. the pterosaurs



-----Original Message-----
From: King, Norm R <NKing@usi.edu>
To: 'dinosaur@usc.edu' <dinosaur@usc.edu>
Date: Tuesday, February 06, 2001 4:53 PM
Subject: RE: The birds vs. the pterosaurs


>I'm doing some more idle yet fevered musing.
>
>From: Larry Febo (Tuesday, February 06, 2001 9:20 AM):
>
>>As for pterosaurs, by the end of the cretaceous, the
>>only existing ones were large, fish eating species,
>>near the top of the food chain, and thus hit very hard.
>
>This seems to be an odd situation where a terrestrial animal (pterosaur) is
>at the top of the aquatic food chain.


Every organism is some part of some food chain. If you can suggest to me
what could have caught and fed upon these large pterosaurs on a regular
basis, then I will have to conceed that they were not at the top of their
particular chain!

>It reminds me of a scene from Walking With Dinosaurs, when a plesiosaur (or
>was it a mosasaur--I don't remember) reached up and captured a theropod.
>Thus, this aquatic animal was clearly at the top of the terrestrial food
>chain.  Actually, I didn't like that hypothesis at all.


I think it was some type of mosasaur, and it`s attack, (if it could have
happened at all), was an unusual event. Hardly what would qualify placing it
at the top of a terrestrial food chain.It seems that the large pterosaurs in
question were specifically adapted for skimming the surface, and catching
fish on a regular basis, thus qualifying their placement as top predators in
this particular food chain. PS,...I don`t believe a food chain has to be
constrained to specific physical boundaries, ie...aquatic vs terestrial or
airborn.


>Back to pterosaurs.  I figured the pterosaurs that survived to the end of
>the Cretaceous, which were flying eaters of fish and therefore dependent on
>sight for finding food, simply couldn't see anything to catch in an
>environment where the brightest light intensity was only a fraction of that
>of the full moon.


Could have been. I was even going to mention this, but again, I think the
root cause of the KT extinction was the short term (couple of months)
depletion of the photosynthetic base of the food chain. That alone would
account for the extinction of some forms, and the survival of others. This
is seen as > the main cause < of the extinctions in the oceans, so why
should terrestrial extinctions at the K-T boundary have some other cause???