Greetings and salutations, and I must say, it's good to have time to be able to read all the posts on the list again. Well enough of the mushy stuff.....
I just got back from vacation (after an extremely busy senior year, that was a welcome relief), and during that (the vacation, that is, not the senior year....*shudders*... :) ) time I had the opportunity to read Xu et al 2001 about Sinornithosaurus millenii. Here's my take on it.
The biggest thing that stuck out of the whole paper (despite the xeroxness of it all) were that the filamentous integument (i.e., the feather clumps). The filaments were all parallel. Now, the paper describes the taphonomy (for those of you who don't know what this means, taphonomy is the study of what happened to the carcass after death, during, before, etc. burial, fossilization, and all the "juicy" details of how the creature lost its juices....) of the animal as lying around for a while before burial. Well, for spending as much time as it did out of burial, those filaments are aweful straight. Not even the burial process curved or bent them to a significant degree (except the example in figure 4). The fact that the paper says that these feathers match the characteristics of downy feathers makes this seem more remarkable. Downy feathers are soft and stuff.... These feathers don't even look frayed. The paper also states that they appear to have been keratinaceous (sp.?), and keratin makes up harder parts like claw sheaths, armor, fingernails, etc..
All this led me to believe that these feathers, and possibly feathers from other non-avian theropods as well, were made of sterner stuff than are modern day feathers. That feathers serves as a self-defense mechanism, not as a give-away-and-leave-the-predator-with-a-mouthful-of-fluff type defense, but as a prickly kind of defense (where's the right technical term when you need it?????). These feathers could've been harder and acted like porcupine needles. They wouldn't have to be too rigid, just prickly enough to hurt, like many cacti do in the American Southwest (I know, I shouldn't compare cacti and dinos, but I think differently than most people so just trust me here....). Spines like these, for obvious reasons, would've been of great use to the animals on their necks. On the limbs and tails they would've been of great use because it would prevent predators from biting them there and dragging them to a better biting position. Larger feathers would've meant that that trait might've passed to offspring, and so larger quills (that's it!! Woohoo!) would've been more attractive to potential mates, and so they got larger. Then they might've gotten flashier to attract mates, and so on and so on.
Then they also could've doubled for flying, swimming, brooding, selling used cars, what have you....
Anywho, *_I_* think it's an idea worthy of further research. Anyone else?? WHO'S WITH ME???? :)