[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Chaoyangopteridae

Imagine the guy standing underneath a flock of them as they flew over, "Oh little bird, up in the sky, you did something in ......" :-)
Other comments inserted below.
JimC

----- Original Message ----- From: "Mark Witton" <Mark.Witton@port.ac.uk>
To: <dinosaur@usc.edu>
Sent: Tuesday, June 03, 2008 2:13 AM
Subject: Re: Chaoyangopteridae


Jim,

Just wondering: do your estimations of lung volume take into account
pulmonary airsacs distributed around the neck, torso and forearm?

Yes. For some years, I have seen pterosaurs as being highly pneumatic. My weight estimation technique allows for the amount of pneumaticity at each cross section to be adjusted. The pumping volume of the torso remains highly limited, and dead air space is a function of that, unless the pumping is being assisted by the flight muscles which is a possibility, but highly speculative.

Patrick O'Connor and chums gave an interesting talk on this at Munich: I
believe there is a paper in the works, but I'm not sure how far along it
is. Certainly the stuff at Munich looked pretty spiffing, so hopefully
it won't be too long in coming.

I look forward to reading that. I've been fascinated with Bill Akersten's work on avian pneumaticity. And, I love the video showing a pelican's leading edge inflating during the flapping stroke.

Oh, and while I'm here and talking about air-filled pterosaurs and
things: for the record, yes, my heavy 250 kg estimations _are_ pretty
much maximum masses. Seeing as my method of skeletal mass/body mass
regression was based around the same regression of modern captive
animals, we should imagine these pterosaurs as healthy, well fed
individuals: you know, the kind of pterosaurs we would expect to see in
zoos. Imagine being the guy would had to shovel the Hatzegopteryx guano.
Ugh.

Or just prior to leaving on a migration. As an example, the Whooper swan 'Stonker' (identified as JAP in research papers), when leaving Iceland for Scotland (and vice-versa) would weigh in at about 13 Kg, 50% more than his average weight, and would burn off as much as half that weight during the course of the flight. Stonker was the largest individual bird known to have flown by means of continuous flapping flight, and was the largest known bird of his species. He also made one of the most remarkable emergency flights I've ever heard about, during a gale off the coast of Iceland. At the end of that flight, he landed at a weight of about 6 Kg. As a fellow pilot, I have the utmost regard for him. Unfortunately, he disappeared during migration several years ago, but he was quite old for a swan, so I guess it was to be expected sooner or later.

All the best,
JimC