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Re: Biggest predators
At 08:53 PM 3/15/99 -0500, Patrick Norton wrote:
>Tom Holtz said:
>>_Deinocheirus_ is not much like these at all. It's claws have a very low
>angle of curvature, they are VERY broad in cross-section, they do not show
>the typical theropod (indeed, basal dinosaurian) deflection of manual digit
>I. Instead, they have the same metacarpal proportions and shapes as
>Is there any evidence that claws do not change allometrically (different
>shapes at different sizes) as do theropod teeth--particularly tyrannosaurid
Funny you should mention that... :-)
Actually, there seems to be very little allometric change in claw shape
among clades of theropods: _Utahraptor_ claws plot among the same field as
_Velociraptor_ claws, big allosaurs with little allosaurs, etc.
There are claws comparable to or larger than _Deinocheirus_' (_Baryonyx_,
_Suchomimus_, _Torvosaurus_, _Dryptosaurus_, etc.) which have greater
curvature, a more oval cross-section, and a tapered length: the more classic
"eagle-talon" like claw, presumably for piercing and holding.
>>Whatever _Deinocheirus_ was doing, it was doing it much more like an
>ornithomimosaur than like allosaurs or dromaeosaurs. <
>And what precisely were ornithomimosaurs doing with those claws anyway?
Hooking and clamping. Hooking and clamping *what*, I don't know: branches
seem a likely candidate, but catching up smaller animals would work, too.
Despite popular (and some techinical) descriptions to the contrary, there is
nothing raptorial about the claws of _Deinocheiurus_. They are fat, poorly
curved, and not very tapered. One of the most informative thing to do with
_Deinocheirus_ claws (on the off chance you happen to have access to casts,
which granted is a very rare thing) is to place one down next to a
_Torvosaurus_ or similar claw. They are very different structures.
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:email@example.com
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661