[Taxacom] Cladifications are NOTclassifications(MonaLisadrooling)

John Grehan jgrehan at sciencebuff.org
Wed Aug 2 13:45:39 CDT 2006


I appear to find myself in agreement with Ken on the problem of classification confusion for those situations where the situation is phylogenetically unsettled. I see this as a separate problem from whether one accepts paraphyletic groups or not. Even though I might, for example, have a bias to restricting Hominidae to the human lineage, and placing only the orangutans and its relatives in the Pongidae, I would not see any need for insisting on that arrangement for everyone else any more than I would accept the inclusion of chimps in Homo (which would also require all fossil hominids to be Homo too). On the other hand I would not use Pongidae as an evolutionary lineage if it did not include humans and hominids.

>From what little I have seen of dinosaur studies it seems that the quality of their character delineation and documentation in the rush to generate phylogenies seems to be just as bad as often in hominid and hominoid studies, so the mess Ken describes does not surprise me.

John Grehan






> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Ken Kinman
> Sent: Wednesday, August 02, 2006 11:52 AM
> To: taxacom at mailman.nhm.ku.edu
> Subject: Re: [Taxacom] Cladifications are
> NOTclassifications(MonaLisadrooling)
> 
> 
>     I think Farnz has it backwards.  The "frequent revision of Linnaean
> names" is definitely NOT a good thing.  Dinosaur systematics has become a
> true "Babel" of conflicting taxonomies.  The large number of analyses and
> phylogenies (cladograms) is wonderful, but the premature translation of
> those conflicting phylogenies into formal classifications has ruined the
> taxonomy.  I prefer to store relatively unstable information in the
> coding.
> Workers with different phylogenies could have different codings of the
> same
> basic classification (a stable listing of included taxa).  Better to
> debate
> over codings rather than prematurely and frequently changing the Linnaean
> names.  Many of the new dinosaur clade names are already being abandoned
> because they were based on homoplasies, and the same thing is going to
> happen to increasingly cladified mammalian classifications (even those
> based
> on molecular data).
> 
>     Informal names for such speculative "clades" are a better alternative
> (e.g., bullatosaurs or clade "X + Y", not Bullatosauria), but the mad rush
> to establish priority for PhyloCode names is unfortunately far stronger
> than
> any calls for a moratorium.  And don't expect molecular data to stabilize
> the situation any time soon, because it is also plagued by problems of
> homoplasy, misrooting, and other complications in phylogeny construction.
> Sorry Farnz, but we need a bigger gap, not a smaller one.  Informal names
> would do just as well at ensuring community-wide access to the products of
> systematic research, and it would avoid a lot of instability, confusion,
> and
> unnecessary formal names (many of which don't turn out to be clades
> anyway).
>   Thank goodness, cladistic botany has largely avoided the mistakes made
> by
> many vertebrate paleontologists and herpetologists.  Peter Stevens'
> angiosperm cladograms are very detailed, but he doesn't formally name all
> those new clades.  That's an excellent example of how it SHOULD be done.
>    -----Ken Kinman
> 
> ********************************
> >   Farnz, N.M., 2005. On the lack of good scientific reasons for the
> >growing phylogeny/classification gap. Cladistics 21(5): 495-500.
> >
> >   Abstract:
> >   An increasing number of phylogenetic analyses is no longer translated
> >into classifications. The resulting phylogeny ⁄ classification gap is
> >undesirable because the precise transmission of phylogenetic insights
> >depends on the frequent revision of Linnaean names. The move away from
> >classifying has numerous correlates. These include: an expanded pool of
> >researchers who are able to produce phylogenetic estimates, a mismatch
> >between the properties of molecular phylogenies and the requirements for
> >verbal Linnaean definitions, the emphasis of statistical representations
> >over the creation and evaluation of scientific terms, and a partial
> >disconnect between the processes of nomenclature and taxonomy. The
> >‘‘taxonomic concept’’ approach allows systematists to express
> their
> >varying perspectives with a high precision and can therefore help reduce
> >the aforementioned gap. The phylogeny ⁄ classification link must
> persist
> >in order to ensure community-wide access to, and continued testing of,
> the
> >products of systematic research.
> >
> 
> 

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