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