[Taxacom] Reptilia (and Hominidae)

[Neil Bell]

Richard Zander wrote:

> Headline: A
> Form of Brown Bear Extinct Across Arctic! This seems no big deal. If
> this were an ecologically important species of another taxon it would
> signal nothing to the public, to evolutionists, to biogeographers, to
> diversity specialists unless they were specialists. What if chimps were
> paraphyletic? Would it be important if the extinct form were forma
> sapiens or not? Rank matters.

I think rank matters because it is there. If it wasn't there, it 
wouldn't matter. Admittedly we would then need to find another way to 
signify the groups that "mattered"; people are familiar with the idea of 
families and species as entities and so attribute value to them, while 
form and variety have connotations of being merely representatives 
(actually I'd prefer to restrict the discussion to ranks above species 
just to avoid the separate issue of what the species boundary is or 
isn't) . I agree that the intangible connotations of value that 
traditional ranks have to non-specialists are perhaps something that we 
need to capitalise on in the current climate, but that's a different 
issue from acknowledging the deficiencies in the current system.

> Your solution, Neil, is I think a third alternative to naming
> autophyletic groups at an appropriate rank or strict monophyly, but it
> is contrary to both phylogenetic and evolutionary taxonomy practice from
> what I understand of it. Can you give an example?

As far as I know what I was describing is pretty much what the phylocode 
proposes, although  of course there are other ways of doing the same 
thing, and the phylocode also proposes other things.




Richard Zander wrote:
> Rank counts. There are only two ways to signal information in
> classifications, and those are rank and groupings. Enforcing monophyly
> limits rank as an informational metric.
>
> The nature of bifurcating trees means that an autophyletic lineage (e.g.
> polar bears) is more closely related to one part of the paraphyletic
> taxon (e.g. one molecular lineage of brown bear) than to another (the
> other molecular lineage. Thus, if the molecular lineages of brown bear
> were named, the polar bear would be a form of a subspecies. Headline: A
> Form of Brown Bear Extinct Across Arctic! This seems no big deal. If
> this were an ecologically important species of another taxon it would
> signal nothing to the public, to evolutionists, to biogeographers, to
> diversity specialists unless they were specialists. What if chimps were
> paraphyletic? Would it be important if the extinct form were forma
> sapiens or not? Rank matters.
>
> The autophyletic cactus family is more closely related to one portion of
> the paraphyletic portulaca family than to another. If the two parts of
> the portulaca family were named as subfamilies, then the cacti would be
> a tribe, but if the two parts of the portulaca family had no real
> distinction then the cacti would have no rank at all.
>
> Your solution, Neil, is I think a third alternative to naming
> autophyletic groups at an appropriate rank or strict monophyly, but it
> is contrary to both phylogenetic and evolutionary taxonomy practice from
> what I understand of it. Can you give an example?
>
> *****************************
> Richard H. Zander 
> Voice: 314-577-0276
> Missouri Botanical Garden
> PO Box 299
> St. Louis, MO 63166-0299 USA
> richard.zander at mobot.org
> Web sites: http://www.mobot.org/plantscience/resbot/
> and http://www.mobot.org/plantscience/bfna/bfnamenu.htm
> *****************************
>
> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu
> [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Neil Bell
> Sent: Tuesday, March 17, 2009 12:02 PM
> To: Taxacom at mailman.nhm.ku.edu
> Subject: Re: [Taxacom] Reptilia (and Hominidae)
>
> I think it's odd that in all of this lengthy and interesting discussion
> about monophyly vs. paraphyly in classifications no-one has mentioned
> rank. Isn't rank clearly the issue, rather than monophyly vs. paraphyly?
> Nearly all of the cited cases of evolutionary information being "lost"
> in monophyletic classifications are where a highly distinctive 
> monophyletic group is derived from within another monophyletic group,
> the remaining members of which are recognisable by possession of a suite
> of plesiomorphic characters and have traditionally been recognised as a 
> taxon. Clearly the ideal solution is to name the larger group (including
> the derived clade), and to also name the derived clade, without then
> being required to name the otherwise unremarkable sister group of the
> derived clade (and probably other groups as well) because the larger and
>
> smaller groups are of different rank. 
>
>
>   


-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Neil E. Bell
Postdoctoral Researcher
(Bryophyte Systematics)
 
Kasvimuseo
PO Box 7
00014 University of Helsinki
FINLAND
 
+358 9 191 24463
neil.bell at helsinki.fi
~~~~~~~~~~~~~~~~~~~~~~~~~~~~