Ok, signing off for a while now. Among other things, the above will get discussed when I get back: the image on the right (from here) might look somewhat, err, 'inspired' if you're familiar with the original produced by Mark Witton (see here and here). So long for now. Oh, actually, one last thing...
You all know that 2008 is Year of the Frog. As I discussed back in December 2007, tiny sums of money (relatively speaking) are all that are needed to get individuals of many endangered amphibians into captivity, and hence away from the chytrid fungus that is making them extinct in the wild. And urgent news is that an effort to save a Mexican species on the brink of extinction, the Mexican Large-crested toad Ollotis cristata [shown here], only requires a further $17,000 to come to completion: a massive effort to save the species has already raised most of the money that was required, with $17,000 (of a required $50,000) being the shortfall. May 5th - or Cinco de Mayo - is Mexico's annual holiday celebrating the 1862 victory of Mexican forces over those of the French, so this is an excellent time to bring attention to this cause: please check out the story at Frog Matters, and spread the word if you can!
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Who knows, maybe the giraffe comparison will become the new standard for giant azhdarchid portrayals. The Japanese site seems to have completely ignored why Mark made the image in the first place - there is no way something dimensionally approaching a giraffe is going to weigh 70 kg. Oh yes, and the pictures of mangled people with animal-like poses is utterly hysterical.
Well, that stings. Not the use of the picture, but the fact that the woman in the photograph is a), much bigger than me (if she's the same size as the scale used in my picture, she's at least 8 ft tall, and b), much more attractive.
Still, where I come from, promoting shameless rip-offs of your work is fighting talk. Hence, to raise the bar in the 'pterosaur pictures to make your jaw drop' competition: ver wonder how big Hatzegopteryx was compared to a fairly typically sized human being? I may have something to say on that at Flickr in the next few days.
Giraffe: "I said to stop paying attention to her. Are you even listening to me?" :)
have fun, Dr. Naish, and take your time - we'll be here whenever you return. we all look forwards to what you will share when you come back.
The item on the left looks like a flint nodule. Not quite dark enough for Brandon though. What the hell is that frog looking thing doing in there?
Re: BlindSquirrel
It was a huge pre-Fortean phenomenon to discover animals trapped inside of rocks. Supposedly happened all the time in quarries--usually frogs and toads, usually alive. The 19th century equivalent of Bigfoot sitings: well known and much publicized in newspapers.
And once, supposedly, a live pterodactyl was found. The whole phenomenon, but especially the pterosaur, gets brought up a lot by creationists looking for "evidence".
We need to figure out what the Japanese site is saying... I was under the impression that it was meant to inform Japanese folks about Mark Witton's ideas, with the artist's own interpretation of Quetzalcoatlus standing next to a giraffe.
We dont need to see it next to a giraffe, we need to see it fly, dammit!
Thats the only `Toad in the hole` in captivity in Brighton museum, correct me if wrong?
That Japanese site also seems to have gotten the lift explanation for airplane wings wrong. Common error though. It shows up a lot.
I love the helpful diagram to show that horses are actually walking on their toes - it looks even more painful than a penguin impression.
Could such gigantic beast fly? Maybe Azhdarchids walked around shallow waters like monsterly four-legged herons or cranes...
Of course, why not?
On the edges of their toenails. Birds walk on their toes.
Because (as I tried to suggest in the previous thread that used a similar illustration) everything we understand about muscle-powered flight in birds suggests that the power required becomes greater than the power available at a body mass of about 20 kg. Based on this knowledge, a 150-250-kg pterosaur would have needed qualitatively different skeletal muscle tissue to pull it off. It's a good question.
But a flying animal does not have to rely solely on continuous muscle powered flight. Argentavis was close to four times the limit and presumably got around by soaring. It seems that takeoff was still a problem for the bird and it was an adept walker (as a result?). I don't believe the mechanics of giant azhdarchids have been studied as in-depth and it would be curious how they dealt with the problems of much more extreme size. You should see Mark's flickr on Hatzegopteryx...
Since the Tertiary was a much warmer world, I presume hurricanes were more frequent and possibly more powerful. How would one of these creatures cope with a category 5 hurricane - or did they rely on high wind speeds to help them take off?
Great conference! I really enjoyed every single presentation. Good work :-)
No. It just needs a few mechanical tricks plus a flight mode that consists of anaerobic bursts plus soaring, and a quadrupedal takeoff technique which is nicely confirmed by the wing bones. The math has been done; check out Jim Cunningham's e-mails to the Dinosaur Mailing List (archives here).
Besides, what else could they have done with those amazing wings and shoulder girdles?
The extra-huge pterosaurs didn't even need wind to take off. Strong winds probably gave them trouble. However, hurricanes come from large temperature contrasts, not from high temperatures alone, and those contrasts were generally small in the Mesozoic, ice-free poles and all.
Argentavis, on the other hand, seems to have relied on strong constant winds.
Picture: Of the three, the one on the left looks most appealing... if still a little tall for me. But I think there's more mileage in the one on the right...
Conference: Fantastic! Darren, I expected to enjoy it a lot, and I enjoyed it all even more than I expected, thanks to all who were there. It seemed amazingly well-organized and 'together' even with some late changes to the line-up of speakers. I took 40 A5 pages of notes, I'm surprised to see.
Year of the Frog: Darren, have you noticed there's a giant frog looking upward on the 'I Am Legend' bus adverts? I don't remember any giant frogs in that film.
Pterosaur flight: I was amazed and gratified that my question 'Was the air they inhabited significantly different from ours?' drew such a response at the conference. For anyone interested, answers given referred to these books:
"Oxygen: the molecule that made the world", by Nick Lane.
"Out of thin air: dinosaurs, birds and earth's ancient atmosphere", by Peter Ward (includes refs. to the papers below)
Dudley R. 1998. Atmospheric oxygen, giant Paleozoic insects and the evolution of aerial locomotor performance. J. Exp. Biol. 201:10431050.
Dudley R, Chai P. 1996. Animal flight mechanics in physically variable gas mixtures. J. Exp. Biol. 199:18811885.
(Ancient flying things and arthropods grew bigger than any we now see. I thought there might be something in the idea of -say- double our present atmospheric pressure in the past. Or more O2. Or something.)
No such thing is necessary to explain even the biggest pterosaurs.
The biggest insects, however, almost certainly show that the atmosphere contained upwards of 30 % oxygen in the Late Carboniferous and (IIRC) Early Permian.