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Re: DINOSAUR digest 3467

Jorge Dichenberg wrote:

Also hand and finger mobility of oviraptorids would be
interesting. I wonder if hand was mobile and grasping,
or like Archeopteryx, a kind of proto-wing with only
claws free, useless for anything but display.

Hopson (2001) showed that the phalangeal proportions of the manus of _Oviraptor_ were similar to the feet of predatory birds.

Maniraptorans appear to have lost a great deal of the mobility within the manus. Gishlick (2001) noted that _Deinonychus_ was incapable of one-handed prehension, and Senter and Parrish (2005) came to the same conclusion for _Chirostenotes_. Oviraptorids were probably the same - especially given that in at least one oviraptorid (_Heyuannia_) the manus shows some carpometacarpal fusion. So, maniraptorans could only grasp objects using both hands, like pincers. This is OK if the maniraptoran is grasping large prey, but extremely unhelpful if the maniraptoran wants to grab small objects.

The presence of wings (or proto-wings) in _Caudipteryx_ and _Protarchaeopteryx_ (basal oviraptorosaurs), _Jinfengopteryx_ (a troodontid?), and microraptorans, as well as birds, suggests that this character is primitive for the Maniraptora - at least using the principal of phylogenetic bracketing. So oviraptorids (and velociraptorines) either retained wings or proto-wings, or secondarily lost them.