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RE: Yet more on pterosaur quad arm posture
It counts as climbing.
What you probably meant to say is that, though flightless, it has inherited
features from ancestors, such as the hallux, that allow it to do this.
Again, for perching adaptations to evolve, there was a population of animals
that went into elevated perches WITHOUT such adaptations, and that provided the
selection pressure for them to evolve. Were basal paravians all doing that, and
did it take until, say the Sapeornis node in Avialae for the arboreal
adaptations to arise?
The only other way it could have happened is if there were exaptations, such as
gripping feet (Fowler et al. 2011), that allowed elevated perches and were
later replaced by reversed halluces. This exaptation is reported for
dromaeosaurs, which are also paravians.
And, when we ask what good the intermediate stages of flapping flight would be,
a valid answer is "to get 1 meter off the ground into a low roost", because
living basal birds (tinamous, galliforms, anatids) still share the character of
roosting this way.
From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] on behalf of David
Sent: Friday, July 12, 2013 9:43 AM
Subject: RE: Yet more on pterosaur quad arm posture
> OK, my incredule, here is a flightless Weka (Gallirallus australis) in a
> And, as I say, chicks and pinioned birds that can't fly do it too.
Let me just quote from what it says under the photo:
"Wekas really aren't meant to be off the ground, and the best part was when
this particular one kept falling off the branch. I saw this silly bird on Ulva
Island, a small island in a bay of Stewart Island."
"The tree was more of a large shrub, and it hopped up from branch to branch."
Seriously, this does not count as climbing.
> Of course Strigops does as well, but it is zygodactylous, after all.
It's a parrot. Parrots _are_ good climbers.