[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
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.