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Re: Dinosaurs and birds



Mike Taylor wrote:

His explanation of this was (again,
from memory) that these "early birds" were small and dwelled in
forests, so fossils would be expected to be pretty scarce. (An
argument that works a lot better for pterosauromorphs and
pan-chiropterans than for avialans, IMHO.)

Also, critters like coelurosauravids, _Longisquama_, _Sharovipteryx_, drepanosaurids, and kuehneosaurids manage to get themselves fossilized.


Why, what arboreal adaptations do oviraptorosaurs have?

Not a whole heckuvalot. Hopson (Ostrom symposium volume) notes that _Protarchaeopteryx_ has hindlimb proportions consistent with arboreality. That's it.


Mike Taylor wrote:

For this reason, Olshevsky proposed the name Brontosauria for a group
uniting Sauropodomopha with Segnosauria, but thankfully this name has
not been used much (in fact, at all, so far as I can tell).

I quite like the name Brontosauria, irrespective of its original content.

In this
formulation, Sauropodomorpha would be paraphyletic, which I guess may
be what Mike (Keesey) was referring to.  But AFAIK George has never
proposed separate origins for sauropods and prosauropods.

I think he does now. Ornithischians and prosauropods are regarded by him (=Olshevsky) as closer to theropods than to sauropods. As Mickey M. said, this kind of scenario illustrates the pitfalls of basing a "phylogeny" on a single character.


Cheers

Tim

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