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Re: BCF (was New Article in Experimental Zoology)

The problem, my dear Stephan, is not - as you correctly point out - a scientific one. I am well aware of this. Most of this discussion has been about the aesthetics of nomenclature. If this is not acceptable to you, please feel free to get the discussion terminated. :-)

The Phylocode has is not yet in effect. Therefore NOW is the time to discuss aesthetics, while the definition is not set in concrete. _Archaeopteryx_ + _ Vultur gryphus_ is a common and well supported definition for Aves. I think it has a better chance of being accepted by the broader scientific community than the more narrow "crown clade" definition of Gauthier's. It certainly has broader support on this list (of many, many future palaeontologists).

If you have taken the time to look at my systematics page (as I know you have) you would know that I am very much in favour of the Phylogenetic System, and I respect Jacques Gauthier and Kevin de Queiroz very much. But as has been pointed out by others that "Aves" means "bird" in many languages, and it would be nice to have the node agree with popular usage as closely as possible.

The "problem" is that _Archaeopteryx_ has overwhelmingly been considered a member of Aves since its discovery, and the common usage of "bird" equates to "feathered flying animal". _Archaeopteryx_ + _ Vultur gryphus_ closely matches the historical, and popular, notions of Aves. These are subjective arguments, but then so are all others when discussing primarily aesthetic matters.

_Archaeopteryx_ + _ Vultur gryphus_ is a compromise definition of Aves, and it matches fairly closely historical and popular usage and classification. Why make radical changes when they are not necessary?

As to your last point:

In
other words, if one is to use a name for a clade, all
should use the same name for the same clade to
eradicate ambiguity.

Agreed. I think most people are using _Archaeopteryx_ + _ Vultur gryphus_. If it proves otherwise, then I will follow suit. But for now, I think the most well accepted and common definition is the _Archaeopteryx_ node.

To quote the dead parrot sketch (how appropriate): "The plumage don't enter into it!". (Or maybe it does.)


On Monday, August 26, 2002, at 11:07  PM, Stephan Pickering wrote:


--- John Conway <john_conway@mac.com> wrote: 

On Monday, August 26, 2002, at 06:12  PM, T. Michael
Keesey wrote:

Since the crown clades match the original content
of such clades as 
_Aves_,
_Mammalia_, _Crocodylia_, etc., and since their
traditional usages 
match the
crown clades more closely than they do the
stem-based clades, it makes 
much
much more sense to apply them to the crown clades
than the stem-based 
clades.
They were originally named for extant forms -- why
should it not
remain so? 

But Gauthier's crown clade Aves excludes so many
animals that most
people would call birds. _Archaeopteryx_ + _ Vultur
gryphus_ is not a
crown clade as I understand it - but makes much more
sense (the common
sort anyhow).

Many people have big problems with any definition of
Aves that excludes
_Archaeopteryx_.


John Conway, Palaeoartist

"All art is quite useless." - Oscar Wilde

Protosite: http://homepage.mac.com/john_conway/
Systematic ramblings:
http://homepage.mac.com/john_conway/phylogenetic/

I'm afraid that all of this circumlocution is
unnecessary, as the bickering does not meet
evidentiary standards of scientific discussion. Mr
Conway concludes: "Many people have big problems with
any definition of Aves that excludes 'Archaeopteryx'".
Many people...who have not read, carefully, Jacques
Gauthier's/Kevin de Queiroz's 2001 phylogenetic
systematics. As they, and other scholars have noted,
there are at least four morphotypes of pre-K/T
feathers known, and, Gauthier/de Queriroz write, "now
feathers are no longer diagnostic of the clade
stemming from the Archaeopteryx node". There are
transformational series: hollow filaments, "natal"
down, pennaceous feathers, remiges and retrices (cf.
Gauthier/de Queiroz 2001:25). There were, simply put,
nonavian theropods with feathers who could, likely,
have flown/glided/become airborn. Gauthier/de Queiroz
make the cogent observation (2001:33): In our view, at
least five clades formerly designated as "Aves"
desedrve to be named in one way or another: (1) the
clade of bird-line archosaurs; (2) the clade of
feathered dinosaurs; (3)the clade of flying dinosaurs;
(4) the clade stemming from the Archaeopteryx node;
and (5) the clade of crown dinosaurs.
    I do not discern the "problem" Mr Conway alludes
to. "Aves" does not equal the Archaeopteryx node. In
other words, if one is to use a name for a clade, all
should use the same name for the same clade to
eradicate ambiguity. Archaeopteryx is a node within
Avialae but not Aves.
    If this not acceptable to Mr Conway, I await his
detailed analyses.

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John Conway, Palaeoartist

"All art is quite useless." - Oscar Wilde

Protosite: http://homepage.mac.com/john_conway/
Systematic ramblings: http://homepage.mac.com/john_conway/phylogenetic/