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Re: Dino/Birds? was Mesozoic snow?
Actually, the discussion pertains to when therapods developed feathers -
though I did pick up currents of rejection of hte entire idea. There are
ongoing rather desperate efforts to reject the notion that therapod
dinosaurs had feathers.
The discussion came from a discussion of Jurassic climate. Question was
whether dinosaurs ever saw snow. I asked, if they didn't, what would they
have needed to develop feathers for. Since birds are about teh only
therapod dinosaurs that ever evolved the ability to fly, dinosaurs clearly
developed feathers for another reason, and insulating body covering is
consistent with being warm blooded. Being warm blooded has a number of
advantages, such as intelligence, speed of locomotion, and speed of growth,
but body covering is specifically an advantage if it is cold. Someone
pointed out that body covering is also an advantage if it is hot or if there
are temperature extremes over the course of a day - but the cold blooded
species all have ways to cope with both situations.
I've not had time to look properly into it, except to look in the book where
I first found it, which doesn't explain. But I had said that the triassic
was a time when Earth's climate got cool and dry. The first ice age did
not occur during the Cenezoic. Actually, the one detail my book does give
is that there is evidence of widespread glaciation during the Permian on one
of the two continents that existed at that time.
I also learned that there was a second major extinction at the end of the
Triassic, due to a large meteorite landing in Quebec, which created the
Manicouagan Crater. This is consistent with the fact that there were ever
more than two layers of iridium. At the same time, there was major
volcanism as the continents rifted.
Also, it says that "climates became more seere, with marked seasonal changes
and aridity in many areas." as the continents changed their location.
----- Original Message -----
From: "Mickey Mortimer" <Mickey_Mortimer111@msn.com>
Sent: Tuesday, June 14, 2005 9:13 PM
Subject: Re: Dino/Birds? was Mesozoic snow?
> Andrew Simpson wrote-
> > I am shocked. We continously being told that all these
> > theropods are feathered. The artists are putting
> > feathers on everything thesedays. But you seem to be
> > saying that we have only two theropods with proof of
> > feathers?
> > Madness.
> > What is up with all those Dino-Birds in china. Are
> > they flat out birds or is there some cross into the
> > dino realm?
> Tim and Tom were only discussing dinosaurs earlier than the Late Jurassic.
> We have many non-bird theropods with preserved feathers-
> Dilong paradoxus
> Sinosauropteryx prima
> Shuvuuia deserti
> Yixianosaurus longimanus
> Beipiaosaurus inexpectus
> Protarchaeopteryx robusta
> Caudipteryx zoui (=C. dongi)
> Pedopenna daohugouensis
> Jinfengopteryx elegans
> Sinornithosaurus millenii
> Cryptovolans pauli
> Microraptor zhaoianus
> Microraptor gui
> Scansoriopteryx heilmanni
> All of these except for Shuvuuia are from China. And much like we can
> safely assume prehistoric mammals had fur, we can assume other related
> dinosaurs (basically every coelurosaur, except maybe large tyrannosaurs)
> were feathered too. None of the above are birds, except perhaps
> Scansoriopteryx and Pedopenna, assuming you don't call Velociraptor a
> There are also a lot of actual birds from the same Chinese deposits,
> from primitive things like Shenzhouraptor to advanced ones like Yanornis.
> Mickey Mortimer
> Undergraduate, Earth and Space Sciences
> University of Washington
> The Theropod Database - http://students.washington.edu/eoraptor/Home.html