Re: Defining clades like a REAL man (Was: New PaleoBios pa

[mike@miketaylor.org.uk (Mike Taylor)]

> Date: Tue, 04 Oct 2005 17:08:38 -0500
> From: Tim Williams <twilliams_alpha@hotmail.com>
> 
>>> The monophyly of Diplodocoidea looks set in stone, but I wouldn't
>>> hold my breath when it comes to resolving the relationships of
>>> many Chinese taxa (_Euhelopus_, _Mamenchisaurus_, _Omeisaurus_,
>>> _Shunosaurus_, etc).
>> 
>> ... which is precisely why it would be premature to erect a clade
>> for those guys.
> 
> Yes, but the family-level names Euhelopodidae, Mamenchisauridae and
> Shunosauridae do exist.

We should treat them the same way Monty Python suggests we treat the
Belgians: "Let's not call them anything, let's just ignore them".
(This should be set in stone as the Python Principle of Taxonomy :-)

> AFAIK, none have phylogenetic definitions.  Should they be defined,
> it would be helpful if the definitions did allow for future changes
> in topology.

Why make a bad situation worse?  There's no need to encourage these
names.  If we just stop using them, they'll go away.

>> Wilson and Sereno's solution in the case of Brachiosauridae was to
>> define a stem-based clade (_Brachiosaurus_ not _Saltasaurus_)
>> rather than a node; which seems eminently sensible.
> 
> Yes, it is sensible.  Eminently so.  But this a stem-based clade; a
> node-based clade would not be so easy for Brachiosauridae.

Why would you want one?

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor  <mike@miketaylor.org.uk>  http://www.miketaylor.org.uk
)_v__/\  The only advantage in making computers understand English is
         that it will prove once and for all that programmers can't
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