Re: Ornithurine diversity

[evelyn sobielski <koreke77@yahoo.de>]

> Well, if ornithurines had speciated to the point of greater
> diversity 
> due in part to competative replacement/exclusion of
> enantiornithines, 
> then their higher species count and larger range of
> ecomorphs would 
> have made them statistically less likely to be totally
> wiped out.

True, but the most specialised ornithurines (Hesperornithes) did not survive - 
not that I'd expect specialized forms to survive an ecosystem collapse. And 
overall, the entiornithine diversity was probably still higher.

More parsimonious explanations might be that (especially Gondwanan) part sof 
the globe which were less affected by the impact(s) hat actually a higher 
diversity of Neornithes still. I am mainly thinking of the Australia-NZ-Byrd 
Land triangle, which was as it seems may well have been settled by basal 
Neornithes *before* Enantiornithes arrived there in numbers - if they ever did. 
But there is just too little material to tell (it stands to note that 
_Nanantius eos_ was apparently a seabird, which is unusual for an 
enantiornithine). From the simple standpoint of parsimony, even the apparent 
lack of a proper fanning tail (unknown in enantis this far) might be 
considered, though I really have no idea how that should help to survive...

That being said, it IS an important study. Conclusions might be premature or 
not, but anything Campanian/Maastrichtian that looks ornithurine is well worth 
a publication in its own right in this listmember's view. There is much insight 
to be found in these bones, for they will tell us more about how what we know 
as birds today birds came to be.


Regards,

Eike


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