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Re: Viva Neornithine Birds!



--- David Marjanovic <david.marjanovic@gmx.at>
schrieb:

> >>That is yet another question. Molecular dating
> argues against the idea 
> >>that
> >>*Polarornis* and *Neogaeornis* were loons --
> >
> > Does it?  Ericson et al. (2004) seems to at first
> glance, until you 
> > realize
> > they only included Tertiary taxa to calibrate
> their divergence dates.  If
> > you ignore the Cretaceous neornithine fossils, of
> course the divergence
> > dates will come out as too late to incorporate
> them.
> 
> No, no, I'm talking about van Tuinen & Hedges
> (2004): when *Polarornis* and 
> *Neogaeornis* are assumed to be either crown gaviids
> or stem gaviiforms and 
> as such used to calibrate molecular dating, the
> results are patently absurd.
> 
> http://dml.cmnh.org/2004Dec/msg00048.html (scroll
> down to "Calibration with 
> Cretaceous loons"). 

FWIW, the Waimanu paper *strongly* indicates that
something like that should have existed then and
there, and that it was not loons, but very likely
close.

And basalmost loons still seem to make good candidates
for C/P survival. Though they would probably be more
like a neoavian version of _Gansus_.

Eike


                
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