[Taxacom] Rankless classifications

John Grehan jgrehan at sciencebuff.org
Fri Mar 20 07:21:52 CDT 2009


Please explain how the group "coelacanths, lungfish & extinct relatives
of tetrapods is is paraphyletic. I can't tell from the daigram as to
what constitutes "extinct relatives of tetrapods". Presumably you know
what they are referring to and that one or more of these is acutally
more closely related to the "four limbs" clade.

Regarding the Sarcopterygii being 'hijacked by strict cladists' to
include all tetrapods, I did not see this same on the cladogram. It
seems to me that the rank of a taxonomic label can be changed by any
systematist, cladist or not, so please explain who the "strict
cladistis" are in this case and what it is about 'strict cladistics'
that necessitates the change in rank that could not be done by any other

"Diapsids excluding archosaurs". What members of those diapsids are
apparently more closely related to the 'anterorbital opening' clade?

I am sympathetic about the lack of familiar taxonomic categories. There
seems to be an explosion of new names for various nodes all over the
place in all groups (plants and animals). I see this absurdity in
hominid evolution where humans are placed in a tribe, and humans and
chimpanzees in a subfamily, all predicated on the systematic arrangement
being a fact.

John Grehan

> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman
> Sent: Thursday, March 19, 2009 7:39 PM
> To: taxacom at mailman.nhm.ku.edu
> Subject: [Taxacom] Rankless classifications
> Dear All,
>        I happened onto an American Museum of Natural History
> diagram/pseudocladogram showing the relationships of vertebrates.  The
> first thing I noticed is that there is no mention of Aves or birds at
> all.  They are buried within group Maniraptors.   A major Class of
> vertebrates doesn't even merit a mention on this large diagram.
>       And also look at the branch splitting off just before the
> tetrapods.  It is called "coelacanths, lungfish & extinct relatives of
> tetrapods" (what a mouthful).  That is because the name Sarcopterygii
> (or sarcopterygians) for this group has been hijacked by strict
> and greatly expanded to include all the tetrapods as well.  The funny
> thing is that this grouping of tetrapod relatives is paraphyletic, and
> this diagram makes it look like it is mono(holo)phyletic.  The same
> problem with the group "Diapsids excluding archosaurs" (no indication
> that it is a paraphyletic grouping).
>       If they include those paraphyletic groupings, they could at the
> very least split the maniraptors into two branches (birds and "other
> maniraptors").  And for heaven's sake, clearly label paraphyletic
> as such!!!  Don't pretend this is a real cladogram or phylogram.  This
> diagram can be seen through the weblink below.
>         ----------Ken Kinman
> http://www.amnh.org/exhibitions/permanent/fossilhalls/vertebrate/
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