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Re: Claw function in Deinonychus



Jaime A. Headden wrote-

<As total length is uncertain for all except a few complete dromaeosaur
specimens, perhaps a comparison of ungual length to another element's length
would be less prone to error.>


While this is certainly true, as noted in the last posts by Mike Habib and
myself, there is a signal albeit a weak one, based on the specimens involved
in. The reason I used body length is that it may more accurately capture mass
estimation and thus applicable to the hypothesis of weight-bearing pursued in
the thread. The use of other elements must bear directly on this issue for
utility, or apply in a way to demonstrate functional applications.

I figure total length estimates can be very biased by varying tail length (which wouldn't affect mass much). For instance, Deinonychus and Microraptor both have tails about five times their femoral length, while NGMC 91 has one ~3.6 times its femoral length.
Mass estimates cube any linear errors made when calculating them, so are even more fickle.


<Sinornithosaurus
 holotype- ungual 35, phalanx 15, femur 148>

Which ungual was this again? As in my previous posts, one projects certain
inconsistencies when measuring incomplete elements.

The holotype pedal ungual II. As detailed in Xu and Wang (2000), although the ungual's distal tip is missing, it can be seen via CAT scan, and thus its size is precisely known.


Mickey Mortimer