Re: more about "feather" find

["David Marjanovic" <david.marjanovic@gmx.at>]

Here's another blog post on it, with links to more.
http://chinleana.blogspot.com/2009/03/new-feathered-cretaceous.html

> It says that a fossil of a small dinosaur of the saurichian line was 
> covered
> with long very primitive feathers.

No, it's an ornithischian, and that's part of why it's such a surprise!!!

> Have any of you looked closely at the fur of a cat?  Some modern mammals
> could be said to have very primitive feathers.

Less so than *Tianyulong*. *Tianyulong* has pretty stiff bristles that were 
half a millimeter thick -- that's more like the keel of a feather than like 
a hair.

http://scienceblogs.com/notrocketscience/2009/03/tianyulong_-_a_fuzzy_dinosaur_that_makes_the_origin_of_feath.php
"They were very gently curved but otherwise rigid - no bends or waves were 
found."

> When did synapsids develop their fibrous body covering?

The docodont *Castorocauda*, closely related to 
Mammalia-in-the-strictest-sense, had fur, but beyond that we don't know. The 
dinocephalian *Estemmenosuchus*, a Middle Permian animal, appears to have 
had naked skin. Somewhere between these two, then... that's a lot of 
space...

> Maybe this is parallel evolution.

Of course. Ornithodirans and synapsids aren't sister-groups. Do the names 
Sauropsida and Theropsida (mind the o!) ring a bell for you?

> Clearly it was an advantage to develop hom[e]othermy.

In some environments, yes.