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