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Re: pterosaur femora sprawl



----- Original Message ----- From: "David Peters" <davidpeters@att.net>
Sent: Wednesday, June 04, 2008 3:19 PM


Tested against _all_ prior contenders, civets/Ptilocercus/and a fossil rostrum (can't recall name) come closest, so the uncertainty is reduced. If you saw what I saw in the skeletons, you'd be on board.

But as long as it isn't published, what point is there in talking about it? As long as we can't see the paper, we can't meaningfully talk about it.


Chalicotheres and anteaters, also knuckle walkers, may have just one day decided to "save their nails." I don't know about how they changed patterns. Were some small and arboreal?

Anteaters, yes: most are still small and arboreal.

Chalicotheres: no, never. And not all even walked on their knuckles. Some were ordinary quadrupeds. Here it looks like the gait changed when the claws became too long and curved.

Either way, it's a single, fairly simple shift on the tree,
so phylogenetic parsimony is probably not the best way to judge the
likelihood of the proposed launch system.

Never discount phylogenetics. It's the key you're trying to ignore because it doesn't fit your paradigm.

Wow. That's strong stuff. That's an extraordinary claim, you know, of the sort that requires extraordinary evidence.


Shake off all prejudices and let the phylogenetic evidence guide you. It's real. It's not made up by engineers.

But it may be all wrong. The characters may be correlated, or fictitious, or devoid of phylogenetic signal, or unordered when they shouldn't be, or partitioned into states in an irreproducible way, or the matrix may be full of typos, or who knows what. Nobody knows as long as it isn't published.


I brought up short-legged, long-handed Nyctosaurus because it would seem it was operating with oversize "crutches" that would not have been able to be angled at a posterior vector for a quad launch that sent the pterosaur forward.

If I've understood the quadrupedal-launching scenario, the forward thrust is provided by the hindlimbs, and the forelimbs just push the animal up. Right?


Silver bullets:

Comparative number of silver bullets, you mean.