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

[dinoboygraphics@aol.com]

"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)."

Indeed, almost as if later workers made poor extrapolations becaues 
they assumed that Ichthyornis and Hesperornis were "birds"...




Scott Hartman
Science Director
Wyoming Dinosaur Center
110 Carter Ranch Rd.
Thermopolis, WY 82443
(800) 455-3466 ext. 230
Cell: (307) 921-8333

www.skeletaldrawing.com


-----Original Message-----
From: Tim Williams <twilliams_alpha@hotmail.com>
To: dinosaur@usc.edu
Sent: Thu, 8 May 2008 7:09 pm
Subject: 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. FÃrbringer
> (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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