First International Phylogenetic Nomenclature Meeting, Paris 2004

T. Michael Keesey mightyodinn at YAHOO.COM
Thu Jul 3 12:12:39 CDT 2003

--- Curtis Clark <jcclark at CSUPOMONA.EDU> wrote:
> At 10:24 AM 7/3/2003 -0700, T. Michael Keesey wrote:
> >I think the Linnaean system is absolutely incompatible with strict monophyly
> >(=holophyly).
> I'm not saying that all clades should be taxa but rather that all taxa
> should be clades.

This still doesn't solve the problem of where to place ancestral species.

You could possibly get around the problem of running out of ranks by leaving
many taxa unnamed, e.g., for Vertebrata, make Classes out of Pteraspidomorphi,
Chondrichthyes (sense stricto), Actinopterygii, Dipnoi, Coelacanthomorpha,
Lissamphibia, Mammalia, Testudines, Lepidosauria, Crocodylia, and Aves. But
then you leave a lot of fossil taxa with no Class (_Ichthyostega_,
_Dimetrodon_, etc.). Furthermore, you have sacrificed such taxa as
Gnathostomata, Osteichthyes, Sarcopterygii, Tetrapoda, Amniota, Sauropsida,
Sauria, and Archosauria. I don't see that keeping the arbitrary ranks is worth
this sacrifice.

I agree that all formal taxa should be clades (or species ... I think), but I
don't see how this is workable with the Linnaean hierarchy of absolute ranks.
Nor do I see the real value of absolute ranks. (Look above -- what is gained by
saying that Dipnoi [lungfishes] and Mammalia are Classes?)

=====> T. Michael Keesey <keesey at>
=====> The Dinosauricon <>
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