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Re: How are columbiformes (doves and pigeons) related to psittaciformes?
From: "David Marjanovic" <email@example.com>
To: "DML" <firstname.lastname@example.org>
Subject: Re: How are columbiformes (doves and pigeons) related to
Date: Mon, 10 May 2004 21:41:14 +0200
> What ARE Mayr's objections to this specimen? I am HOPING this isn't
> based solely on the stratigraphic location....
The stratigraphic location, and the several synapomorphies that the jaw
shares with _lorisids_, with a _part_ of the _crown group_ of
Psittaciformes. The oldest known parrot-beaked parrots (still not lorisids,
AFAIK) are Oligocene, none are known from the rich deposits of the Eocene
earlier. There are several bird clades from that time and place for which
don't know skull material, plus we don't know when e. g. confuciusornithids
really died out, and in addition there are definitely unknown Cretaceous
bird clades waiting to be discovered, so assigning that isolated lower jaw
to a part of the crown-group just because it shares a few characters with
that clade seems premature to them... and me.
> caenagnathid synapomorphies are found in crown parrots as well, and this
> does not absolve the avian features of the jaw that caenagnathids lack
> the Lance jaw possesses.
Mayr et al. don't say it's a caenagnathid.
I would quite agree that assigning an isolated and rather fragmentary lower
jaw to crown orders is not particularly merited. Problems are after all
legion in using fragmentary material to identify Cretaceous or even Tertiary
birds, which has been noted before (e.g., Olson 1985a) and marvelously
demonstrated by the example of *Limnofregata azygosternon* (Olson 1977b).
As for the whole issue of pigeon/dove relationships...I find the papers
cited by several of you most interesting to be sure, but am still cautious
on the matter and would agree with Sibley & Ahlquist (1990) in stating only
that Columbiformes have no close living relatives, and that sandgrouse are
not closely related thereto.
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