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Re: Mesozoic snow?
Amtoine Grant wrote:
What feathered reptiles were these? Are you referring to Longisquama?
AFAIK, there are supposed feather impressions were a dilophosaur sat,
although some[maybe most] people claim that these are drag marks.
You're absolutely right. The 'feather' imprints appear in reality to be
drag marks in very thick and very slick mud.
The earliest undisputedly feathered dinosaur is Archaeopteryx, if I recall
correctly, from the Late Jurassic.
Yep - with the emphasis on 'undisputed'. We have direct proof of feathers
in _Archaeopteryx_, but not for any other pre-Cretaceous theropod (or
anything else, for that matter). Phylogenetic bracketing would suggest that
all coelurosaurs either have feathers, or are descended from taxa that did.
Theropods like _Ornitholestes_ and _Gasosaurus_ fall into this category,
although their feathers (if present) would have have been of the downy,
non-pennaceous variety ('dino-fuzz'). After all, if tyrannosauorids did,
why not these guys? Of course, theropods might have been primitively fuzzy,
so _Coelophysis_ and _Zupaysaurus_ might have been fuzzy too. But these
taxa currently fall outside the bracket for this character.
The larger branches that could get get by by virtue of their size's
heat-retainment would not have needed to.
Downy body covering might have been advantageous to the young'ns, no matter
how big the grown-ups got.