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RE: Martin 2004 critique

Mickey Mortimer wrote:

"Protarchaeopteryx has typically avian teeth and there is no reason to doubt that it is avian." I suppose if maniraptorans are birds in Martin's mind, that's true enough.
The long primaries of Caudipteryx are said to "so greatly reduce the usefulness of the hand for grasping that it must imply derivation from an arboreal flyer/glider." Someone hasn't read Gishlick (2001) I see.

Martin may be on to something here. Allthough it is possible (and maybe even likely) that the hands could support both a wing *and* continue to be used as a prey-catching instrument, these dual purposes must have had an uneasy relationship. Those big feathers sticking out of the wrist and manus could have interfered with prey capture by the hands, and those same feathers could get damaged (or bloodied) by struggling prey.

According to Gishlick (2001), the manus lost most of its grasping and raking ability by the eumaniraptoran stage, courtesy of the great length and reduced mobility of the manual phalanges. Gishlick proposed that dromaeosaurids like _Deinonychus_ and _Velociraptor_ siezed and held prey in a two-handed fashion. This is consistent with the hypothesis that the larger dromaeosaurids targeted prey of larger or comparable size to themselves (e.g., tenontosaurs or protoceratopsians). But I find it different to imagine the usefulness of long, immobile hands in the smaller maniraptorans. Maybe it is the result of an "arboreal flyer/glider" stage?

"An arboreal stage is further supported by a reflexed hallux on the foot in
all of these forms." Someone hasn't read Middleton's work either.

I can forgive Martin in this case. So far, only a small portion of Middleton's thesis work has been published:

Middleton K.M. (2001) The morphological basis of hallucal orientation in extant birds. J. Morphol. 250: 51-60.

Middleton's work on hallucal orientation in fossil birds and non-avian theropods is also extremely interesting, and I'm looking forward to seeing it published. According to Middleton's thesis, the notion that basal birds (such as _Archaeopteryx_) and certain non-avian theropods (such as _Microraptor_) have a reversed (=opposable) hallux is based on two assumptions: (1) the preserved orientation of the hallux in a fossil reflects its orientation of the hallux in life; (2) an elongated and/or distally-positioned hallux implies that the hallux was reversed. Neither assumption is supported by the morphology or articulation of the first metatarsal in these taxa. A true 'perching pes' did not evolve until fairly late in avialan evolution, well above _Archaeopteryx_.