Message 2004-10-0055: Re: Panstems

Mon, 13 Sep 2004 16:38:07 -0700 (PDT)

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Date: Mon, 13 Sep 2004 16:38:07 -0700 (PDT)
From: [unknown]
Subject: Re: Panstems

Christopher Taylor ( 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=
would currently hold it to include one of these three. But among othe=
taxa that have been suggested in the past to be the most divergent li=
birds are Mesitornithidae, _Opisthocomus_ and _Todus_ (!). Conceivabl=
y, we
could get a situation where these are not Aves. By some older molecul=
phylogenies, Passeriformes would not even be Aves by the definition g=
What to do?>

  I don't see a problem. Under either of the two current definitions =
Aves, one crown-based and the other a node-based clade including
*Archaeopteryx* + living birds, the topology of living birds remains =
part of Aves, and even a part of the crown clade, no matter how they =
arranged. By these two definitions, or even using Neornithes for the =
crown clade (rendered a homodefinitional synonym of crown=3DAves), al=
living birds are members of the crown (Aves or Neornithes). The probl=
with the bird topology above would posit that Passeriformes wouldn't =
part of the same node including galloanserans + other living neognath=
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=
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=
of anatomical study, than *Vultur* would be, based on their shear num=

  Thus, in Article 11, a recommendation or rule (thereabouts in 11.8-=
or so) to advocate use of a living specifier could be made for the mo=
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=
is, and I think only a few people will agree however, rather disparat=
with the general impression of birds (largely composed of songbirds, =
vultures) most people will have.


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)

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