Re: Evidence For a Feathered Velociraptor...

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

----- Original Message ----- 
From: "Dora Smith" <villandra@austin.rr.com>
Sent: Friday, September 21, 2007 2:02 AM

> I know it's heresy to point this out - but dinosaurs first had feathers for
> warmth.   And probably also for display.

Heresy? That has been orthodoxy for 11 years (since the discovery of 
*Sinosauropteryx*).

> But I read both the Yahoo news article, adn the Discovery news article, 
> and
> it's missing some key information.

No, the fossil is missing some key information.

> Where on its body did Velociraptor have these feathers?

We have no idea, because the direct evidence for feathers is limited to the 
quill knobs, which show that wing feathers were present on the forearm. (Or, 
strictly speaking, on the middle 1/3 of the forearm.) However, wing feathers 
are a specialized sort of feathers, so an animal that has only them and no 
other feathers would be unexpected, and we already know that, whenever 
preservation allows it, maniraptorans in general have feathers all over, so 
the simplest assumption is that *Velociraptor* was feathered all over, too.

An interesting question is whether wing feathers were also present along the 
hand, including the 2nd finger, but the fossil doesn't tell that.

----- Original Message ----- 
From: "Dann Pigdon" <dannj@alphalink.com.au>
Sent: Friday, September 21, 2007 4:02 AM

> That may be true of adult animals, but what of juveniles with their
> relatively longer forelimbs and much smaller mass? Perhaps dromaeosaurs in
> general out-grew their ability to fly (or at least 'flutter').

Interesting idea.

> We know from fossils that juvenile dromaeosaurids had fully-developed
> feathered fans on their forelimbs.

One of them anyway (NGMC 91).

----- Original Message -----
From: "Tim Williams" <twilliams_alpha@hotmail.com>
Sent: Friday, September 21, 2007 4:50 AM

> Guy Leahy wrote:
> > As the authors note, the presence of quill knobs in> Velociraptor is 
> > consistent with the idea, championed> by Gregory Paul and others, that 
> > dromaeosaurs were> secondarily flightless, as flightless birds are less> 
> > likely to possess quill knobs.
>
> Turner &c. are a little more circumspect, saying "This [quill knobs in 
> _Velociraptor_] raises the possibility that ulnar papillar reduction or 
> absence in large-bodied derived dromaeosaurids reflects loss of 
> aerodynamic capabilities from the clade's ancestral members.  Quill knobs 
> in _Velociraptor_ could reflect retention of feathers from smaller 
> possibly volant ancestors, but such feathers may have had other 
> functions."  The way I read it, "aerodynamic capabilities" could mean 
> powered flight, or something less demanding in terms of aerial behavior 
> (e.g., parachuting, gliding).

It could be anything -- steering while running just as well as VLOP. 
Parachuting and gliding are IMHO less likely, because for those you need to 
climb first...

> However, it raises interesting questions as to *why* _Velociraptor_ 
> actually retained feathers on its arms.  For a predator that used its 
> hands to grasp prey, what use would feathers be?  I'd have thought that 
> long forelimb feathers would be as useful as tits on a bull.  In other 
> words, worse than useless.  Wouldn't forelimb feathers be an almighty 
> hindrance when the predator was grappling with prey (a la the 
> _Velociraptor_ vs _Protoceratops_ fighting dinosaurs)?

As was beautifully illustrated for the 1st time in 2001 (Ostrom Symposium 
volume), full-grown wings wouldn't matter much, because the feathers are at 
90° to the claws and tangential to the prey. Grasp the screen in front of 
you with both hands: your wing feathers would point downward.