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Re: Fw: Dinosaurs and birds
Don Ohmes wrote:
But! What about bats and pteros? I mean, pteros and bats? No handy feathers
Pterosaurs and bats are assumed to have evolved from patagial gliders.
Unfortunately there is no direct evidence of what the incipient flight
apparatus of basal pterosauromorphs or basal "panchiropterans" may have
looked like. However, in pteros and bats both the forelimbs and hindlimbs
were/are incorporated into a continuous flight surface, which suggests that
they evolved from quadrupedal gliders that had this same arrangement.
Birds, on the other hand, evolved from terrestrial bipeds. Even though
maniraptoran theropods may have passed through some kind of facultatively
arboreal quadruped stage on the way to flight, their morphology essentially
remained that of a biped. Also, the initial stages of the evolution of
flight might have evolved on the ground, so many scenarios hypothesize that
incipient wings first evolved in terrestrial theropods.
Still, pterosaurs might have evolved from bipeds, especially if pterosaurs
are avemetatarsalians. I don't know much about the (undescribed) archosaurs
from Texas that have been interpreted as basal pterosauromorphs
("Pteromimidae"). Such as if they shed any light on the origin of pterosaur
flight, for example.
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