Re: birds and avians again

["Jaime A. Headden" <qilongia@yahoo.com>]

Mike Keesey (tmk@dinosauricon.com) wrote:

<<"Bird" is a vernacular English term and hence its usage is dictated by the  
English-speaking
public at large. I think it's pretty clear that most types of dinosaur do not 
fall under the
common usage of "bird".>>

George Olshevsky (Dinogeorge@aol.com) wrote:

<This is merely a historical accident that I think should be rectified. We now 
know that dinosaurs
are more closely related to modern birds than they are to any other group of 
living animals. So it
makes a lot of sense to expand the definition of "bird" to include dinosaurs 
and any other
archosaurs that fall into the stem-group "birds" that I described. As far as 
formal naming of
these groups goes, one could stick with a node-based Aves (Latin root "birds") 
for the clade
including and descended from the last common ancestor of Archaeopteryx and 
modern birds, a la
Linnaeus, and then name the more inclusive stem-group birds Ornithes (Greek 
root "birds"). (But I
don't like pinning a major group like Aves to a single genus such as 
Archaeopteryx: if we find a
slightly pre-archaeopterygid fossil flying bird, why arbitrarily exclude it 
from Aves?) The other
extant archosaur crown group would retain the familiar node-based name 
Crocodylia, and the more
inclusive stem-group crocodiles (all archosaurs more closely related to 
Crocodylia than to
Ornithes) would become Suchia.>

  I hate to be a rainy day in Seattle, but I would like to know what you think 
others would take
to calling placodonts "turtles" or "chelonians", especially Gaffney and those 
whose primary worl
is with turtles. Gaffney, as you may know, is a phylogenetic operator in a 
cladistic scheme, as
are most AMNH workers. Gaffney is also the leading authority on fossil turtles.

  Such redefinitions are unneccesary, in my view, as they only tend to confused 
the association of
terminology and clades, and would seriously screw with history. And aesthetics. 
The term bird does
not in any way encompass titanosaurs in it's historic, aesthetic, visial, or 
mental paradigm, for
anyone, I think, except George at this point. I would like to know a concensus 
of the listmembers
on what they think a "crocodile" or member of Crocodylia is compsed of, but we 
have done "bird" to
death, and most everyone on this list anyway, appears to be in agreement with 
the historic method.
I am curious if this is the public that must be informed, those who work on the 
animals
themselves. In any way, shape or form, the term bird does not bring to mind a 
titanosaur,
quadrupedal and armorod, unfeathered, a long tail, no pygostyle, a propubic hip 
arrangement, no
beak, no folding wrist, a humeus that could not elevate, no reversed hallux, 
certainly not a
similar palatal arrangement, etc.... These do not incorporate anyone's view of 
the term "bird" or
the idea of Aves. By similar token, it is uneccessary to name a clade Ornithes 
unless one wishes
to define it to include dinosaurs and birds in the aconventional model, where 
they are kept as
separate "classes" of some sort.

  Please note, I am not in any way a conformist, but I cannot see the logic in 
this revisionary
system that attempts to apply a strict vernacular idea to fossils, based on 
extant relationships.

Archosauria: *Crocodilus* + *Corvus* [Neornithes, but we should use a a 
specific genus, and the
      crow is more familiar to the world than just a sparrow is, so is 
emminently more viable in
      my mind.]
Aves: *Archaeopteryx* + *Corvus*

  I beleive both Chelonia and Crocodylia use fossil specifiers/anchors, but I 
cannot recall them
off the top of my head. Tetrapoda as well. Amniota is a stem excluding 
lissamphibians, and
Synapsida is a stem from Sauropsida, or conventionally, Reptilia. Reptilia is a 
crown group clade
comprising Chelonia, Lepidosauria [incl. snakes and mosasaurs], Crocodylia, and 
Dinosauria [incl.
birds]. That these groups are already viable and the vernacular applies to them 
easily, it would
seem that the only reason they should not be used is the basis of fossils. 
However, the fossils
themselves are well-founbed and studied, and do not shift substantially. 
Reptilia will always
include Chelonia, regardless of which diapsid group it is closest to, or 
whether it is not at all.
The crown group for birds can be Neornithes, and we can be satisfied.

  Take the Encyclopaedia Brittanica, for instance: Vol. 2, [pg. 229-230] "bird, 
warm-blooded
vertebrate of the class Aves, unique in having feathers and forelimbs modified 
into wings."
*Archaeopteryx* is treated as the most primitive bird. You will find similar 
definitions in more
complicated texts, including the Encyclopedia of Dinosaurs, Dingus and Rowe's 
Mistaken Extinction, etc..

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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