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Re: Pterosaur diversity (was: Re: Waimanu)


----- Original Message ----- From: "Michael Habib" <mhabib5@jhmi.edu>
To: "dinosaur" <dinosaur@usc.edu>
Sent: Tuesday, May 30, 2006 12:08 PM
Subject: Pterosaur diversity (was: Re: Waimanu)



Today's marine soarers care for non-flying baby for several months.  This
requires a predator-free island with close-by resources.

No, it doesn't require the latter. Albatrosses have been reported to have flown for up to 10,000 miles non-stop (I've not made an independent check to see how true that statement is). In any event, they routinely make very long flights while foraging, and are gone from the nest for significant durations. Sailplanes with performance similar to Quetz have been flown for more than 300 miles non-stop, and that is without the Quetz flap-gliding capability for extending non-stop range.

I think it is premature to make provisioning arguments at this time for all marine soarers of all clades. It is certainly something to keep in mind, though.

Well said.
I'll let Jim handle this, as he is the one that made the comment and has worked out the launch parameters. I'll just say that 1) yes he means a standing start and 2) be careful not to assume that performance must be limited by size. Launch rate in large soaring birds is constrained by size because of the particular way in which they launch. A quadrapedal pterosaur would have a very different launch system (one that allows them to use the forelimbs in launching; a very important point).

You handled it just fine far as I'm concerned. I'm not an evangelist for my views, but a quadrupedal launch is by far the most expeditious for a large pterosaur, and does not require the exhorbitant power requirements that other launch modes do.

I would be interested on your view about pterosaur latitudinal distribution and fish abundance in tropical vs. arctic regions.

They are known as far north as Alberta (however far north that was in the late Cretaceous :-)
Marine going species could have foraged at least another few hundred miles north of that.