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APTERYX AND PROTOBIRD PHYLOGENY
In regards to Ralph Miller's question on paired oviducts in birds, the
best known example is _Apteryx_ the kiwi. As Alan Brush has pointed
out, hawks, falcons, storks and some other birds also have
(occasionally) paired oviducts. Pierce Brodkorb, when he was still into
neornithology, described paired oviducts in the Marsh hawk, but I forget
Anyway, a few weeks ago Greg Paul made the claim that the lack of
reversed halluces (not "halluxes") in the Chinese "protobirds",
_Caudipteryx_ and _Protarchaeopteryx_, really doesn't mean that they
cannot be more derived than _Archaeopteryx_ because _Apteryx_ also lacks
a reversed hallux. I didn't want to make a premature criticism so I
looked at some refs and some actual kiwi specimens just to make sure;
anyway, _Apteryx_ does have a reversed hallux as far as I can tell. It
is positioned rather proximally on the tarsometatarsus, but the position
seems to be reversed.
What does this tell us? For one, it casts doubt on the assumption that
the two "protobirds" are more derived than the famed _Archaeopteryx_
sp.. At the moment, I think that the best interpretation is to consider
them outside of Aves (_Archaeopteryx_ + Neornithes). The real question
is, where do they fit? I think that for the moment, _Protarchaeopteryx_
should be considered next to Dromaeosauridae, possibly allied with
Velociraptorinae, and _Caudipteryx_ should be considered next to Aves as
the sister group to the _Unenlagia_ + _Archaeopteryx_ + _Rahonavis_
group that Forster et al. considered.
I must repeat again that the two animals show hardly any features that
suggest that they are closer to Neornithes than _Archaeopteryx_ (ie.
lack of dorsal ischial processes, presense of serrated teeth, two
sternal plates, etc.). The sternal characters and tail characters are
rather meaningless, both can be considered homoplastic in light of the
estensive avian characters that _Archaeopteryx_ has.
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