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Re: Different twist of BCF



In reply to Ronald Orenstein:
 
> I doubt that even George Olshevsky would go along with that one. While it
> is true that the Enantiornithines became extinct at the K-T boundary, they
> were not the earliest line of Mesozoic birds. In addition, they are not the
> only group of Mesozoic birds to disappear prior to or at the K-T .

Hesperornithiforms and ichthyornithiformes also disappeared, as well 
as critters like the patagopterygids and mononykosaurs.  What's 
surprising is not just the phylogenetic diversity of birds in the 
Late Cretaceous, but their ecological diversity as well - of the 
Ornithurae and Enantiornithes alike. 

> Unless I am much mistaken, birds like Sinornis or even Hesperornis
> are not considered to be enantiornithine.

_Sinornis_ is still regarded as an enantiornithine, AFAIK.  

> Thus it is incorrect to assume that the enantiornithine line is so
> similar to the basic stock from which birds evolved that it could be
> regarded as an ancestor to the so-called dino-birds - assuming that
> these creatures evolved from birds at all.

Agreed.  Sounds like the old "Sauriurae vs Ornithurae" dichotomy - 
_Archaeopteryx_ and enantiornithines get put in the Sauriurae, and 
neornithines, ichthyornithiforms, hesperornithiforms, etc make up the 
Ornithurae.  I believe that Alan Feduccia is quite keen on the idea.  
It makes it a lot easier for him to crank the origin of the birds 
back to the Triassic if _Archaeopteryx_'s lineage diverged from the 
ornithurines a long time before the Late Jurassic.  All a load of 
codswallop if you ask me.