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Re: [dinosaur] Fwd: Tyrrell's 1884 Albertosaurus skull + early bird liftoffs + near-dinosaurs + larval temnospondyl + more
Brad McFeeters <firstname.lastname@example.org> wrote:
> Does anyone think that Yi was not an arboreal theropod?
(1) I don't know. (Speaking solely for myself.)
(2) Even if _Yi_ was an arboreal theropod, it has no bearing on the
origins of arboreality and/or flight in birds. As the original
description states: "they [scansoriopterygids] appear to represent a
case of extreme morphological divergence near the origin of birds" So
scansoriopterygids appears to be an aberrant/'oddball' group.
(3) It seems likely that _Yi_ was capable of some form of aerial
locomotion. But without knowing the exact morphology or extent of the
patagium, it's difficult to infer what kind of aerial locomotion. If
_Yi_ was capable of launching from the ground, it could reach tree
branches without climbing. So it could be arboreal without being
scansorial. If _Yi_ could pull off patagium-driven "ground-up"
launches, then there might be parallels between 'flight' in
scansoriopterygids and the evolution of pterosaur flight. Pterosaur
ancestors likely had strong erect hindlimbs, as in _Scleromochlus_ and
dinosauromorphs (e.g., Witton DOI 10.7717/peerj.1018); and saltatorial
abilities in _Scleromochlus_ (http://
would be consistent with a terrestrial leaping origin for pterosaur
flight. But I'm straying OT here....