Deinonychus claws again

[tlford@ix.netcom.com (Tracy Ford)]

Well, I had a very busy day. I finished up my theropod lips article and 
sent it off to the Mesa South West Museum, Jim Kirkland, Will Elder's 
and my abstract for Dinofest. Running around to work, gas, kinkos, 
postoffice then hitting a movie all before 2 and then going to a Padre 
game that night (for the Sky Show, a fireworks show that needs to be 
seen to believe).

It's my birthday, and instead of going to a bar after the show to 
celibrate, what do I do, go to the San Diego Natural History Museum for 
45 minutes to look at once again, the Jurassic Park show. A true dino 
nut.

What the #$%^ does this have to do with Deinonychus? Well, they have 4 
mounted skeletons in a running pose is what. I thought, hey, I'll check 
out the feet. All but one foot had Mt II in a flexed postion. The one 
that didn't have it flexed had the toe next to the others in in the 
last phase of the foot before it is brought forward. The length of the 
claw in that position is just short of Mt III. In this position, 
takeing the length of the claw into factor, the foot isn't all that 
different from other theropods. Some of the Deinonychii had the Mt II 
pulled back like G. Paul depicts them, others had them just like how 
Ostrom drew them in the Osteology that he wrote. 

What I think of all of this is that I really want to get my hands on a 
good cast, totally disarticualted, so I could articulated each and 
every bone to see just how far it could articulate. 

The peduncle on Mt II is actually small in comparison to that of the 
manus. (I'm looking at Ostrom's 1969 osteology, not the pictures in 
Dinosauria). Yes, all the tips of the manus claws are broken off, so is 
Mt II. No I don't think it walked on all fours. I don't know of any 
living animal that keeps any toe in a retracted position. If any one 
does know, please I'd like to see it, article, picture, what ever. I'm 
not talking about cat's claws, sloth's etc. IMHO, looking at the side 
view of the pes in Ostrom's monograph and articulating the toe, similar 
to what P. Sholly had done, it does work. This is a relaxed state. The 
toe in that position does explain the sherd off tip of the claw. Mt III 
also has a sherd off tip. The claw of Mt II, the one that EVERYONE 
draws is actually a 'special' case. As I've stated before, other claws 
have a claw in a less curved state, which I take as the norm. 

I would also not object to the claw the toe being held slightly up and 
the claw held, not in the pulled back pose, but with the claw in an 
in-between, horzontal, pose. The total degree of flexation of the claw 
is vast, and the claw is thin (Ostrom, 1969, page 135), the 
articulation is from phalange II and not I. The Proximal end of Mt III 
and IV have the most curvature for the phalanges to move, while Mt II 
(at least from the drawing) not much movement at all, and Mt I, it 
looks like no movement, just the claw moved (and  yes, it is on the 
back of Mt II, this is constantly being misdrawn, even by ME!, 
something I have to remember!). In Utahraptor's case, probably had a 
'razor' type edge (Jim Kirkland pers. comm.), so I wouldn't abject to 
all dromaeosaurids with this type of claw. John Sibbick has greatly 
imporved and I really like his current work, but the Dinosaurs painting 
is, as Pete pointed out, not one of his more accurate works. He didn't 
show the pad where the claw mets the phalange, which would be large, he 
also didn't show the pads on the manus either. 

I've also wondered about how it attacted using it's hands. The hands, 
when relaxed, was palm to palm, just like a bird due to the semi-lunate 
carpals (Jurassic Park did get that right when what's his face was 
talking about the 'in situ' dromaeosaurid). Then when it attacked, they 
used a 'wing' beat, bring the hands, up, out, then in (Kevin Padian did 
a marvelous job of explaining this years ago, and I'll never forget 
it). Now for pure speculation, dinosaurs didn't start to fly from, 
running, or glideing, but from an attacking behavior. The furcula would 
aid greatly during the attack and add thrust. Perhaps, either finding 
this to a great advantage, they then used it to learn to fly, or, found 
it easier, in some cases, to deevolove from a flying mode to a pure 
attacking mode.

All this works on paper, but I really, REALLY want to look at an 
actuall specimen or a cast to see what really works.

Well, I think that enough, time for bed (1:30 am and all).

Tracy