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Re: Feathered Dragons: Studies on the Transition from Dinosaurs to Birds
Jon Barber wrote-
> > > I'm all for putting _Microraptor_ and _Archaeopteryx_ up in the
> >I'm not. Evidence against a retroverted hallux in the latter,
> Really? I hadn't heard this. Do you have any references?
Middleton, 2003. Morphology, evolution and function of the avian hallux.
unpublished thesis, UMI 3087312. ii-147.
Middleton, 2002. EVOLUTION OF THE PERCHING FOOT IN THEROPODS. JVP 22(3) 88A.
Living birds reverse their halluces by twisting the metatarsal, not just
rotating it around the pes. Rotating the metatarsal around the pes wouldn't
work because it would block tendons. Wellnhoferia doesn't have a twisted
metatarsal I, and the other archaeopterygid specimens are too poorly
preserved to tell. No non-avian theropod studied by Middleton does either,
including Caudipteryx and Protarchaeopterys Rahonavis and Patagopteryx
don't as well. Confuciusornithids and enantiornithines do though. I can't
tell the condition in Sapeornis, though Omnivoropteryx might have the twist.
Scansoriopteryx looks to have only a slight twist, if any.