[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Cetartiodactyla (& dismantling Condylarthra)

I encourage constructive griping....er... I mean, criticism. :-) Artiodactyliformes is not, I repeat, NOT a new name. Artiodactyla was simply emended with a standard suffix in my 1994 classification. The author of the emended name remains the same as it was, just as with the many names that have been emended in Treatise on Invertebrate Paleontology over the years, giving invertebrate orders a standardized -ida suffix. It's still the same taxon and author (only the ending has changed, and you can do computer searchs for various spellings simultaneously using truncation and other tools). I am emending names, not "making up" new ones, but you seem to be seeing semantic hurdles that aren't there. There are enough real hurdles to jump over to be wasting time jumping where hurdles don't exist.
And if Mesonychia (emended to Mesonychiformes) is paraphyletic rather holophyletic, the Kinman System can very simply change the coding to reflect that. In my 1994 classification I coded Mesonychiformes as sister group to the whales. If Mesonychiformes is really paraphyletic with respect to Cetiformes, I would just change the coding symbol to show that whales are an exgroup rather than a sister group. If Mesonychiformes is instead paraphyletic to some other exgroup, I will just move that order after it (instead of Cetiformes). Cetiformes would presumably then be placed right after Artiodactyliformes.
If a "whippomorpha" clade gets consistent support, I can show Artiodactyla (which I emended to Artiodactyliformes) as being paraphyletic and indicating Cetiformes is its exgroup, plus the {{Cetiformes}} marker next to the Family Hippopotamidae within Artiodactyliformes. I could code that marker to show whales as sister group to Family Hippopotamidae, or even as an exgroup to that family if whales are shown to have a sister group relationship to a particular genus (or group of genera) within that family. For the most part the taxa remain stable, and we can reflect most changes by just modifying the coding sequence next to them (and maybe occasionally move a taxon up or down relative to the others in the classification).
It's just a more flexible way to cladistically nest taxa. You still have your sister group information, but fewer formal taxa cluttering the landscape, eclecticists won't be breathing down your necks, and stability is enhanced. And the Kinman System does not mandate the emended standardized names. You can use the traditional spellings and are free to forego the long-term benefits I think standardization will have. And the coding works with intermediate level taxa (I try to discourage their use, but it works fine if you want to put them in). But others may choose to use informal names and coding to do the same thing, once they see the advantages. It really is a lot more flexible than you might imagine. Try it, you might like it.
P.S. I did away with Condylarthra altogether, and split is into several separate Orders (one being Mesonychiformes, formerly a suborder IIRC). Would you really prefer me to go back to a Condylarthra that was at best paraphyletic, but more probably polyphyletic? I hope not. Who knows, I might even do away with Thecodontiformes (my most criticized taxon) when we have enough information to split it up with relative confidence. That may happen within a few years---- but not until Dilkes and Merck have published their papers. I'm not opposed to abandoning traditional taxa once they have outlived their usefulness (and did so with Condylarthra and other groups as well). Why McKenna retained the name Condylarthra for a small piece of its former self is beyond me.
From: "Jaime A. Headden" <qilongia@yahoo.com>
Reply-To: qilongia@yahoo.com
To: dinosaur@usc.edu
CC: kinman@hotmail.com
Subject: Re: Cetartiodactyla (was Re: Cladistic taxonomy (was Dietary factors))
Date: Wed, 9 May 2001 19:55:24 -0700 (PDT)

Watch out, I'm griping again.

Ken Kinman (kinman@hotmail.com) wrote:

<That sounds very interesting.  I recognize a separate Order
Mesonychiformes, so no matter how it and artiodactyls and
cetaceans are interrelated, I will be able to reflect it in my
classifications without having to change the contents of any of
these three orders.>

  Except that Mesonychia itself has been suggested to be
paraphyletic, in the same analyses that suggested they were not
ancestral to whales, and one other (sorry, I don't have the
paper, but I can dig up the cite....). Making up a
"Mesonychiformes" is irrelevant.

<Therefore retaining the traditional Artiodactyliformes (without
cetaceans) gives me more flexibility.  Whether it is
paraphyletic (gave rise to cetaceans) or holophyletic, I still
have the same stable groups (Orders) and can reflect all these
controversial interrelationships with an easily modified coding

  I'm afraid that there is nothing "traditional" about
Artiodactyliformes. It didn't exist in the traditionalist era we
consider "traditional" and is quite new. First semantic hurdle.
Next one... Artiodactyla will be monophyeletic even if Cetacea
is the sister group, as it does not rely on whales in its
compsosition. Phylogenetics suggest that whales are the sister
group to artiodactyls, not artiodactyls themselves. So questions
on monophyly, holophyly, or paraphyly are irrelevant unless you
want to support your statements with explicit information.

Jaime A. Headden

  Where the Wind Comes Sweeping Down the Pampas!!!!

Do You Yahoo!?
Yahoo! Auctions - buy the things you want at great prices
Get your FREE download of MSN Explorer at http://explorer.msn.com