Talk:Cephalopoda

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==Alternative Taxonomy==
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First of all, forgive me again for being so brash as to put my latest discussion at the top. If this is too radical for anyone, go ahead and bury it at the bottom.
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And, yes I'm back.
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The class Cephalopoda near the top of the article is divided into three superclasses, as generally  perceived, the '''Nautilioidea''', '''Ammonoidea''', and '''Coleoidea'''.  Bactritoidea and Belemnoidea, sometimes separated out, are presumed included in the Ammonoidea and Coleoidea.  This sense is repeated in the summary phylogenetic diagram,  just below.  All well and good.
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Further down under Alternative Taxonomies, four Infraclasses are shown. Nothing wrong with infraclass, if that's what works best but I propose superorders instead, as that follows Wade 1988 in the literature.
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They are the:
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*Pletronoceratoidea, containing the Plectronocerida, Yanhecerida, Protactinocerida, and Ellemerocerida.
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*Endoceratoidea containing the Endocerida, and if ordinally distinct, the Intejocerida.
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*Discosoritoidea, for the Discosorida
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*Actinoceratoidea, for the Actinocerida
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*Nautilitoidea, which includeS the Tarphycerida, Oncocerida, and Nautilida.
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*Orthoceratoidea which includes the Orthocerida, Ascocerida, and Pseuorthocerida as well as the Dissidocerida
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The Infraclass Ammonoidea is, in the scheme at the top of the page, the Subclass Ammonoidea and should be retained as such.  Whether superorders can be formed from ammonoid orders is another thing.  The Anarcestida, Goniatitida, Prolecanitida, and even Clymediida might be comblined in, lets call it the Goniatitoidea. The Ceratitida is a Triassic complex all of its own.  The Phyllocerida, Lytocerida, Ammonitida, and Ancyclocerida can all be combined in what might be called the Ammonitoidea.
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The Taxonomy of Mary Wade, 1988, seems to me to present a more accurate phylogenitic picture of the Cephalopoda than that of Curt Teichert, which seems to be a rehash of older and sometimes antiquated ideas, revived near the end of his days.
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I plan on making the changes, pending comment and after posting a few new articles on major cephalopod taxa, still missing.
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Regards [[user: John M|John]]  8/06/10
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:Hi John, do you know if anybody has published a detailed discussion of phylogenetic relationships among 'ellesmeroceratoid' taxa (using the term in its broadest sense sensu ''Treatise'') and their connection to later cephalopods? I know the ''Treatise'' suggests connections between certain families and later orders but in a decidedly vague manner. It'd be nice if there was anything more definite.[[User:Christopher|Christopher]] 00:22, 7 August 2010 (UTC)
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==Phylogeny(Dendrogram) ==
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Fellow cephabuffs.
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Forgive me first for sticking this on top, but I figured it'd be more in the limelight. If anyone cares to respond it might be a good idea to place whatever directly underneath. So much for procedure.
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I may be a little confused as to how to read the dendrogram under Phylogeny. Setting aside the list of  genera un assigned to any higher taxa the list of suprafamilials at the bottom could be misleading.  May I suggest the following ememdation, with explanation.
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''Plectronoceras'' in an excellent place to start, even for the whole shabang, being the oldest known cephalopod, known from as early as the Franconian, lower Yenchou, of China. I added the Ellesmerocerida which are the root stock of all post Cambrian cephalopods.  The Endocerida and Actinocerida are shown slightly differently to allow for the added Orthocerida. All three are independently derived from the Ellesmerocerida. The Orthocerida provides a place for the Bactrida to attach. Stemming from the Bactida are three independent groups, the Ammonidea, Aulacocerida (Belemnoidea) , and Coleoidea. The line of direct decent from the Ellesmerocerida continues to the Nautilida, which along with the Coleoidea contains the most recent cephalopods.
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  ''Plectronoceras''
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    `-+- Ellesmerocerida (''added'')
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      |---Endoceratoidea
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      |---Actinoceratoidea
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      |--+-Orthocerida (''added'')
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      |  `-+-Bactritida [Bactritoidea]
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      |    |--[Ammonoidea]
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      |    |-- Aulicocerida
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      |    `--[[Coleoidea]]
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      `--[[Nautilida]]
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Regards[[user: John M|John]] 3/10/09
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:Thanks, I've incorporated some of your suggestions (and removed the unplaced taxa to below the tree). I have converted the ''Treatise'' classification into a dendrogram, but it's going to need some checking over before I load it up here (and I've got a fair amount of other stuff queued up before it), so don't wait for my edits - just go ahead with your own. [[User:Christopher|Christopher]] 00:46, 11 March 2009 (UTC)
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Hi anyone and everyone.
Hi anyone and everyone.
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Best regards, John M
Best regards, John M
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:Thanks for your comments, John. The reference list includes the sources for the names listed in the dendrogram. I've changed the heading "References" to "Dendrogram Sources" to make this clearer - hopefully, as I track down those names in more appropriate sources, I'll be able to eliminate the less appropriate references.
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:An artificial classification is one that has been composed on the basis of a very small number of fairly superficial characters, without necessarily reflecting the true relationships of the organisms involved. For instance, nautiloids in the broad sense are largely united only by by their simple septa, a primitive feature that hides the high diversity of nautiloid body forms, and that some nautiloids are both more closely related and more similar to ammonoids than to other "nautiloids". I do disagree with your statement that "''Paraphyletic taxa allows derived forms to quite sensibly be given equal or even higher rank than their immediate ancestors. Otherwise there is the taxonomic problem of diminishing returns''". This is only potentially an issue if rank is a concern in the first place, and it is amply demonstrated that the use of ranks is positively misleading about diversity. No ranks - no problem.--[[User:Christopher|Christopher]] 23:42, 14 October 2008 (UTC)
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==Nautiloidea "valid"?==
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I've already noted my objections to regarding Nautiloidea as "valid". I'm not going to change John's usage of it in the article (I can't see that turning into anything other than a flame war, and I don't see how that would benefit anyone). But would "widely used" or "generally recognised" potentially be more neutral alternatives? [[User:Christopher|Christopher]] 07:32, 2 August 2009 (UTC)
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== Infraclass/Superorder==
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Hi again, and after somewhat of a break.
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You may notice that at the top we have three principal cephalopod groups listed at subclasses, following current convention. Further down class Cephalopoda is subdivided rather into infraclasses.  First off, unless both are needed, is there much of a difference between  and infraclass and a superorder. Since subclass is a higher ranked taxon and I believe takes precedence one needs a subclass to infra. On the other hand doesn't superorder imply orders to super. Getting back on track Mary Wade, 1988, proposed (used) superorders which fit rather well into the infraclass scheme presented.  I suggest for the impertinent sake of conformity that infraclass be changed to superorder, with subclasses retained.  Just a thought.
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Cheers.  [[user:John M|JohnM]]11/30/11

Latest revision as of 02:31, 1 December 2011

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