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Re: Aeolosaurus colhuehuapensis n sp



T. Michael Keesey writes:
 > > I don't think it's wise, even though it's allowed: it's a name
 > > that commits the authors to a specific (and quite precise)
 > > phylogenetic hypothesis.  By naming the new taxon _Aeolosaurus
 > > colhuehuapensis_, the authors are asserting that it is more
 > > closely related to _rionegrinus_ than to any other named sauropod
 > > genus: not something I'd be quick to do on the basis of (all
 > > together now) a series of eroded caudals.
 > 
 > Well, that's assuming _Aelosaurus_ is a clade--it's never been
 > defined as such.

There are good reasons not to define genera as clades; but even in the
absence of such a definition, I think even the sternest traditional
Linnaean would agree that monophyly of genera is desirable when
possible.

 > There's a big trend in systematics to make genera monophyletic.
 > This is going to break down at some point--not every species can be
 > placed in a monophyletic genus unless we allow genera to contain
 > other genera. The final common ancestor of dinosaurs, for example,
 > could not be placed into a monophyletic genus unless it included
 > all dinosaurs.

Indeed.

But that would be no reason to go making paraphyletic genera down at
the level of Aeolosaurus.  In fact, I find it impossible to think what
the authors possibly mean by referring the new species to that genus
_except that_ it is more closely related to the type genus than to any
other named genus or species.  Really, what other conviction could
induce someone to raise a new species within an existing genus?

(My radical solution to the binomial problem: leave genera alone and
abolish species instead.  Bam, done.)

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor    <mike@indexdata.com>    http://www.miketaylor.org.uk
)_v__/\  "That which gets lost in translation" -- Robert Frost's definition
         of poetry.