Re: Climbing in theropods: extant and extinct

["Tim Williams" <twilliams_alpha@hotmail.com>]

Nick Gardner" <ratites637@hotmail.com> wrote:

> Are there special adaptions in the ankle and knee joints of parrots that 
> permit them to be so flexible or would these have been present in theropods 
> as well?

One thing to note is that in birds the ancestral knee (the joint between the 
femur and tibiotarsus) functions in hindlimb rotation, since the femur juts 
nearly straight forward and usually doesn't take part in locomotion.  The 
functional knee has moved down to the tibiotarsal-tarsometatarsal joint.

Psittacine birds have zygodactyl toes, which are especially well adapted for 
grasping branches (among othr things).  No known non-avian theropod has this 
feature.



Tim

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