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Re: Greg Paul's new (or newly named) iguanodonts



On Dec 6, 2007 3:33 PM, Tim Williams <twilliams_alpha@hotmail.com> wrote:
>
> On thing that I noticed about Paul's paper is his attitude to phylogenetic 
> taxonomy.  For example...
>
[...]
> "The only cladistic designation for iguanodonts below the 
> Ouranosaurus-hadrosaur clade is the unwieldy 'non-hadrosauroid 
> iguanodontoids',
> in which the members are described by what they do not belong to as much as 
> what they do belong to.

Yes, that's what a paraphyletic group is. The terminology may be
unwieldy, but it accurately reflects that fact. Calling the group
Iguanodontidae, OTOH, would make it seem the same type of taxon as
Hadrosauridae.

> "This sort of taxonomic arrangement is technically
> inconsistent, as well as discriminatory, towards taxa that do not happen to 
> belong to
> modest sized, terminal monophyletic groups.

This argument is bizarre to me. First of, what is a terminal
monophyletic group? What would a non-terminal monophyletic group be?

Second of all, the only discrimination here is in the actual
evolutionary history of the group. Iguanodontids (sensu Sereno) were
not as successful as hadrosaurids -- period. Are we to blame that on
nomenclature? Should monotremes blame systematists for the fact that
they are languishing while therians prosper? Life isn't fair -- why
should our nomenclature pretend that it is?

Anyway, all that aside, I'm glad the wastebasket of _Iguanodon_ is
finally being cleaned out and the relationships of its former members
clarified. Looking forward to reading the full paper.
-- 
T. Michael Keesey
Director of Technology
Exopolis, Inc.
2894 Rowena Avenue Ste. B
Los Angeles, California 90039
http://exopolis.com/
--
http://3lbmonkeybrain.blogspot.com/