Riversleigh is early Miocene, isn't it? (It seems to
oscillate in the
literature between Oligocene and Miocene.)
At least the Riversleigh cockatoo is early Miocene IIRC. The original
description is doi:10.1111/j.1474-919X.1993.tb02804.x
> too [few] cladistic studies with comprehensive
sampling exist for reasons
> unknown
The reason is very simple: a morphological cladistic
analysis of any kind of
decent size is at least a chapter of a PhD thesis.
Yes, but it's just as bad with molecular studies. Astuti has 2-3 nice ones
(including the thesis), but apart from that it's just in-depth looks at
particular clades, or very coarse general papers. The former is highly
useful to me personally, but in the general scheme of things it's almost
non-informative: the clades are usually Neotropical psittaciforms, which
is about as far from base as one can get.
There is an _Agapornis_ or two (or something as similar to these as the
Riversleigh fossil is to _Cacatua_) from Langebaanweg, a few Ma later than
the cockatoo. This is highly valuable because it proves that the clade
Mayr discusses was not only distinct ~20 mya, but that it had already
radiated and dispersed. Its origin is in the general region of New Guinea
as surely as this can be said in the absence of basal fossils. Oh, and the
budgie is part of it too as it seems - it would thus have an interesting
combination of plesiomorphic overall pattern and mildly apomorphic
coloration among the crown Psittaciformes.
But the most interesting psittaciform probably still is the large species
of Easter Island. A quadrate piece of a bird with a head size comparable
to a kakapo. Nothing new on this since it was described nearly 15 years
ago. Quaternary of course, but if anything even more tantalizing than
_Mopsitta_. It might just about carry enough information to apply the
results of the phylogenetic analyses to it, but I have not seen a photo of
the wretched thing, and the description of the specimen was in a
small-circulation journal. The Mascarenes taxa OTOH have recently been
reviewed in Zootaxa and little questions remain.
Regards,
Eike
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