Wednesday, January 07, 2009

Confusing Pterosaur Take-Offs

This confuses me greatly. According to a new paper published in Zitteliana by Mike Habib, pterosaurs launched themselves into the skies quadrapedally with a "leap-frog" motion. I cannot, for the life of me, envision this. I remember seeing this concept as a poster session at last year's SVP, but there, as here, there are no figures showing exactly how this would work. What we really need is an animation. Can somebody explain this one to me?

Ridiculously awesome update: In the comments, Christopher pointed to the launch sequence of a vampire bat. I'm sold, and it would probably work for rhamphorhynchoids, too.


ScottE said...

I thought this was pretty keen, and is a great explanation for how they could get so big.

It takes off by jumping from all four limbs, not just the hindlimbs.

I'd love to do a stop-motion model animation of this, to illustrate it though. (Even with just an armature!)

Will Baird said...

I buy it for the pteradactyloids, but what about the tailed bunch? Would this work?

Christopher said...

I think it must help a lot if you have seen footage of vampire bats launching, because it is the exact same method that pterosaurs use. I have seen such footage on tv so that must be why I find it strange that this isnt just completely intuitive for everyone.

Anyway, I tried looking for a photo sequence but couldn't find one. I did find this schematic:

And heres a photo of a bat at the end of the launch sequence, just before it starts the flap cycle.

And I see no reason why it wouldnt work for a rhamphorhynchoid grade pterosaur.

John Jackson said...

In some ways the ideal way for an animal to leap up is to extend itself, throwing as many bits upwards as possible and leaving the ground when fully stretched and the extremeties moving as fast as possible, but for things with relatively strong front limbs, using them to push up with allows stronger muscles to be used. I can't remember if the vampire bats I saw on TV gave themselves upwards velocity using their arms then finished off with a foot push, or whether the arms left the ground with or after the back legs.