RE: Combined answer: smallest ANCIENT non-bird dinosaur - was what I was asking

[Tim Williams <twilliams_alpha@hotmail.com>]

David Marjanovic wrote:


> I think many would prefer it if the only alternative were accepting
> *Utahraptor* as a bird, though. What if Archie is a troodontid and
> deinonychosaur...?


If _Utahraptor_ was a "bird", would that really be so bad?  If deinonychosaurs 
are demonstrated to lie between _Archaeopteryx_ and modern birds in theropod 
phylogeny, then I think all deinonychosaurs deserve to be called "birds".  If 
you showed a drawing of _Microraptor_ or _Jinfengopteryx_ to the average member 
of the public, I don't think he or she would hesitate in calling it a "bird".  
They have wings, feathers, and look like they were capable of some kind of 
aerial locomotion.  From a purely typological/platonic perspective, they are no 
more or less a "bird" than _Archaeopteryx_.  


As a vernacular word, "bird" is a fairly elastic term, and it includes a vast 
array of fairly disparate (morphologically) forms - _Archaeopteryx_, 
_Confuciusornis_, _Patagopteryx_, _Hesperornis_, ostrich, kiwi, hummingbird, 
penguin, chicken, condor...  You don't need to stretch the trem "bird" too far 
to include deinonychosaurs (even _Utahraptor_).  When _Rahonavis_ was first 
described it was regarded as a "bird", and no one batted an eyelid (apart from 
Feduucia &c).   For deinonychosaurs as whole, it's only by virtue of this group 
lying outside the _Archaeopteryx_+Neornithes clade that prevents them from 
being termed "birds" already.


> I disagree. All usages of Neornithes that I've seen that included
> *Hesperornis* and/or *Ichthyornis* seem to have been made in the context of
> the hypothesis that these animals really were crown-birds. Fürbringer
> (1888 -- yes, I've seen that book) explicitly said so (except of course in
> different terms), and for much of the 20th century it was thought that,
> while the hesperorniths were outside the crown because of their teeth and
> other features, the toothed jaws associated with *Ichthyornis* actually
> belonged to a juvenile mosasaur and that *I.* was a crown-bird; perhaps I
> can check Martin 1983 tomorrow, but this paper is in any case in the right
> timeframe for this hypothesis.


Yes, that's my impression too.  For the longest time both _Ichthyornis_ and 
_Hesperornis_ were allied with grebes and loons - although Marsh had originally 
separated them from the crown-group (as Odontornithes).


Cheers

Tim
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