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RE: Microraptor and Birds

Thomas R. Holtz, Jr. wrote:

First off, we have the horrendously difficult (if not impossible) situation
in trying to test for powered flight in fossil taxa.

Bloody hell, yes! There is still no unanimous agreement on the matter of whether _Archaeopteryx_ was even capable of sustained (powered) aerial flight . (See Chatterjee and Templin's (2003) paper on "phugoid gliding" in _Archaeopteryx_ for an example.) Then there's that little matter of whether dromaeosaurids and _Caudipteryx_ were secondarily flightless.

Secondly, if we change
this to simply the (easier to demonstrate if taphonomy is correct) presence
of feathered wings (and we agree that feathers require rhacis, barbs, and
barbules), then Avialae would encompass deinonychosaurs and oviraptorosaurs,
too.

This would conform to de Queiroz and Gauthier's (2001) definition of the clade Aviremigia, a more inclusive clade than Avialae.


T. Michael Keesey wrote:

Or, as I suggested a while back on the list, "Enigmoraptora" ("enigmatic
raiders")or "Enigmodracones" (sp? "enigmatic dragons"). "-sauria" is so
overused (and kinda inaccurate....)

I would suggest resurrecting the names Caenagnathiformes (taxa closer to _Caenagnathus_ than to _Archaeopteryx_) and Archaeopterygiformes (taxa closer to _Archaeopteryx_ than to _Caenagnathus_) to subdivide the "higher" Maniraptora.

The problem is, if you derive a clade name from a genus name (e.g., Enigmosauria, Hadrosauria, Titanosauria), the two requirements should be (1) the nominative genus is valid, and (2) the nominative genus actually belongs in the clade. Thus, as Mike stated, the clades ought to be anchored in the nominative genus (or species), vis-a-vis PhyloCode.

The pitfall with descriptive names (e.g., Arctometatarsalia, Maniraptora, Saurischia) is that some or most of the constituent taxa may lack the nominative characters. For example, among maniraptorans, the deinonychosaurs (dromaeosaurids more so than troodontids) are exceptional in having a highly refined raptorial manus; other maniraptorans (alvarezsaurids, oviraptorosaurs, therizinosaurs, non-basal birds) probably did not use their hands in predation (for alvarezsaurids, _Caudipteryx_ and modern birds, this is a given). Still, pandas are undoubted members of the Carnivora, and kiwis will always be in the Avialae. So, this is less of a big deal than some people make it out to be.




Tim

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