Predictivity & Tetrapoda nightmare

Edwards Jr, G.B. edwardg at DOACS.STATE.FL.US
Wed Feb 16 09:43:54 CST 2005


As a relatively recent subscriber to TAXACOM, I'm sure I've missed out
on previous interesting discussions.  But I would like to comment on
Curtis Clark's contention, since no one else is.
...
>And you didn't address my contention that since Reptilia offers nothing
>beyond the information contained in its defining clades, it is
superfluous.
>--
>Curtis Clark

As an invertebrate systematist [which, I'm sure my other
invertebrate-studying colleagues would agree, is an advantage since we
have to deal with the diversity of orders of magnitude more species than
the vertebrate-studying types], I've for a long time thought that this
contention was obvious since the classic Reptilia, like the Amphibia
'before' it, was based on an 'improved' level of organization (at least
that was what I was taught in high school) rather than a phylogenetic
concept.  But not knowing a whole lot about the details, I went to the
website suggested by Ken Kinman to brush up on vertebrate
classification.  Looking at the general phylogenetic organization, I
made the following observations.

Maintaining the classic Reptilia as a formal, all-encompassing taxon
(i.e., including all the descendents from the node 'Reptilia') is like
putting all synapsids in Mammalia (especially if you consider 'balance'
to be important in a classification).  Actually, if you go farther back,
all the above are in the Osteichthyes, but we don't consider them all
fishes.  So why should we consider all Reptilia to be 'reptiles?'  And
it unnecessarily complicates classification efforts by imagining
paraphyly where none exists.  It basically boils down to an argument
over semantics that has nothing to do with classification.

Consider the following:
(1) Reptilia is the name of non-mammalian (and related) anthracosaurs,
like Synapsida is the name of non-reptilian (and related) anthracosaurs
(as above, Reptilia are no more all 'reptiles' than synapsids are all
mammals); maybe this group should have been called something like
'Reptilomorpha' to eliminate all this confusion about Reptilia with
'reptiles;'
(2) If turtles aren't diapsids, then they're 'testudine anapsid
reptiloids;'
(3) Modern 'reptiles' are synonymous with Lepidosauromorpha.  This
eliminates the illusion of paraphyly and doesn't require the invention
of ex-groups.  Surely someone has suggested this already, but I don't
keep up with vertebrate systematics literature. 

At least that's what it looks like to me, based on the web trees, and
without delving into further details.

Just out of curiosity, does a nominal type species of Reptilia exist?

 -- 
G. B. Edwards, Ph.D.  [Your Friendly Neighborhood Spiderman] 
-- 
Curator: Arachnida (except Acari), Myriapoda, Terrestrial Crustacea,
Thysanoptera 
Florida State Collection of Arthropods, FDACS, Division of Plant
Industry 
P.O.Box 147100, 1911 SW 34th St., Gainesville, FL 32614-7100 USA 
(352) 372-3505 x194; fax (352) 334-0737; edwardg at doacs.state.fl.us 
http://www.fsca.entomology.museum/Arachnida/ArachnidaFrame.htm 
-- 
Board of Directors, Center for Systematic Entomology:
http://www.centerforsystematicentomology.org
Editor, Peckhamia; Membership Secretary, Peckham Society
Co-Coordinator, Florida Arthropod and Arthropod Pathogen Introduction
Committee 
Courtesy Professor, Department of Entomology and Nematology, University
of Florida
 

-----Original Message-----
From: Taxacom Discussion List [mailto:TAXACOM at LISTSERV.NHM.KU.EDU] On
Behalf Of Curtis Clark
Sent: Sunday, February 13, 2005 1:13 PM
To: TAXACOM at LISTSERV.NHM.KU.EDU
Subject: Re: [TAXACOM] Predictivity & Tetrapoda nightmare

on 2005-02-13 09:51 Ken Kinman wrote:
> Okay Curtis, You want to bring up the herpetological mess again,
> fine.  Predict for me whether the Tree of Life classifies
> Acanthostega, Ichthyostega, Seymouria, temnospondyls, etc. as
> Tetrapoda.

I predict that they are not amniotes.

> Turtles are likely to be Diapsida that have
> lost the diapsid condition (predictivity has been almost worthless
> trying to place them).

Wouldn't it be nice to actually know, rather than classify (either
monophyletically or paraphyletically) based on our ignorance?

And you didn't address my contention that since Reptilia offers nothing
beyond the information contained in its defining clades, it is
superfluous.

--
Curtis Clark                  http://www.csupomona.edu/~jcclark/
Web Coordinator, Cal Poly Pomona                 +1 909 979 6371
Professor, Biological Sciences                   +1 909 869 4062




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