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Date: Mon, 13 Sep 2004 16:38:07 -0700 (PDT)
From: [unknown]
To: dinosaur@usc.edu, phylocode@ouvaxa.cats.ohiou.edu
Cc: ck.taylor@auckland.ac.nz
Subject: Re: Panstems
Christopher Taylor (ck.taylor@auckland.ac.nz) wrote:
<Mike defines Panaves as the panstem clade of the node Struthio + Tet=
rao +
Vultur. Under the current popular phylogenies, this wouldn't really b=
e a
problem - whichever the most basal branch of Aves is, most researcher=
s
would currently hold it to include one of these three. But among othe=
r
taxa that have been suggested in the past to be the most divergent li=
ving
birds are Mesitornithidae, _Opisthocomus_ and _Todus_ (!). Conceivabl=
y, we
could get a situation where these are not Aves. By some older molecul=
ar
phylogenies, Passeriformes would not even be Aves by the definition g=
iven.
What to do?>
I don't see a problem. Under either of the two current definitions =
of
Aves, one crown-based and the other a node-based clade including
*Archaeopteryx* + living birds, the topology of living birds remains =
a
part of Aves, and even a part of the crown clade, no matter how they =
are
arranged. By these two definitions, or even using Neornithes for the =
avian
crown clade (rendered a homodefinitional synonym of crown=3DAves), al=
l
living birds are members of the crown (Aves or Neornithes). The probl=
em
with the bird topology above would posit that Passeriformes wouldn't =
be
part of the same node including galloanserans + other living neognath=
s,
would still be a member of Neognathae {*Vultur* <- *Struthio*}, but
apparently not of Neoaves {*Vultur* <- *Gallus*, *Anser*, *Struthio*}=
.
On another note:
I, personally, prefer *Passer* (sparrow) or *Corvus* (crow) as the
specifier, not *Vultur,* given that the two passerine birds are 1) mo=
re
common than *Vultur* (*Vultur* is largely isolated to one continent,
whereas *Passer* [and indeed, *Passer domesticus*] is of Laurasian
distribution, and *Corvus* [though not any particular species thereof=
] are
of nearly global distribution, save Antarctica), and 2) more prevalen=
t in
collections or readily available to be made in collections for the pu=
rpose
of anatomical study, than *Vultur* would be, based on their shear num=
bers.
Thus, in Article 11, a recommendation or rule (thereabouts in 11.8-=
11.9
or so) to advocate use of a living specifier could be made for the mo=
st
PREVALENT or AVAILABLE species for research purposes, prior to any
particular honorific. Another recommendation about finding the oldest
established name available to be included as a specifier, will allow
people to choose, as well. The use of *Vultur* as a specifier for bir=
ds
is, and I think only a few people will agree however, rather disparat=
e
with the general impression of birds (largely composed of songbirds, =
not
vultures) most people will have.
Cheers,
=3D=3D=3D=3D=3D
Jaime A. Headden
Little steps are often the hardest to take. We are too used to mak=
ing leaps in the face of adversity, that a simple skip is so hard to =
do. We should all learn to walk soft, walk small, see the world arou=
nd us rather than zoom by it.
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
=09=09
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