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Talk:Nymphaeales

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This is an old revision of this page, as edited by Josh Grosse (talk | contribs) at 01:51, 20 March 2004. The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

If this were combined with hierarchal taxonomy, then the Nymphaeales must be placed into their own class, Nymphaeopsida.

If integrated with a hierarchial taxonomy that rejected paraphyletic groups, that would be true. One would also need classes Austrobaleyopsida and Amborellopsida, possibly a few more. But as far as I can tell, this has never been done. Nymphaeopsida has been used, but it's really hard to tell if it's ever been used in the sense given here. Hard-core monophyletics seem content to go without classes. As such, shouldn't the above be tempered somewhat, to reflect how uncommon the system it's proposing is?


Groan. Hierarchical taxonomy is inching closer to phylogenetic correctness. I agree that the other groups you mentioned would be necessary. So what? We're using taxoboxes of hierarchical taxonomy. If you feel this way, then I guess what I need to do is to start adding a second taxobox to each page to reflect the PhyloCode. jaknouse 18:52, 19 Mar 2004 (UTC)

The hierarchial taxonomy as given on this page does reflect phylogeny, but includes a paraphyletic group. There's still debate over how valid those are, but there are good arguments for them, and so we shouldn't assume they'll be dismantled. Thus, it would be fair to mention Nymphaeopsida in the sense given, but not as if it were an inevitable thing. In general, I'm all for preferring holophyletic classes when there are several different options, but not for inventing them.

How does PhyloCode treat these organisms? It treats the Nymphaeales as a direct subgroup of the Magnoliophyta. In short, its classification is simply the hierarchial one with paraphyletic taxa removed. This will always be the case, except in some cases where it requires intermediate clades that don't show up in the other system. As such, it will rarely be worth a separate listing. I can think of three alternate approaches:

  • Leave the taxobox as is, and discuss the difference in the text. This is more or less done here, but could possibly use some emphasis.
  • Mark paraphyletic groups in the taxobox, so people interested in the clades will know to ignore them.
  • Omit paraphyletic taxa - for instance, Nymphaeales wouldn't be given a class.

In some cases, however, paraphyletic taxa are necessary to giving an adequate placement. We could skip them here by using Rosopsida for the tricolpates. However, classes like Reptilia are somewhat harder to get rid of, and trying to force their treatment as several different groups of amniotes has worked poorly in the past. In fact, it is impossible to give a comprehensive classification of extinct creatures without paraphyletic taxa. -- Josh