Re: How are columbiformes (doves and pigeons) related to psittaciformes?

["Jaime A. Headden" <qilongia@yahoo.com>]

David Marjanovic (david.marjanovic@gmx.at) wrote:

<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 or earlier. There are several bird clades from that time and
place for which we 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.>

  These would be Loriidae, not Lorisidae (Primates).

  The presence of a beaked jaw with loriid synapomorphies may likely be
convergent. There is a lot to say for this, and this is almost ENTIRELY
stratigraphic as David supports (but doesn't tell me what Gerald Mayr
actually said). It would not matter that the Paleo-, Eo-, and Miocene
separated this form from the first, earliest known parrot-beaked bird --
if this form bears those synapomorphies (as both Clarke and Stidham have
said) and is avian, and is a higher land bird, the evidence weighs
strongly in favor of it being psittaciform, as well as a crown parrot.
That said, the distinctive vascularization is suggestive of loriid
affinities: parrots MAY have an incredibly old lineage. The jaw is very
peculiar and "advanced" for the typical Mesozoic/Paleogene avian taxa of
it's time.

<Mayr et al. don't say it's a caenagnathid.>

  Never said they did. This was THE reaction after "A Cretaceous parrot?
WOW!" and Clarke made mention of it in the Ostrom volume. The implication
was that other than parrots, only caenagnathid theropods had dentary
symphyses of such a form, so became the obvious contending taxon for
affinities.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


        
                
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