Talk:Bilateria

From Wikipedia, the free encyclopedia

	Bilateria is within the scope of WikiProject Animals, an attempt to better organize information in articles related to animals and zoology. For more information, visit the project page.	Animals Portal
Start	This article has been rated as Start-class on the quality scale.
Top	This article has been rated as Top-importance on the importance scale.
WikiProject Animals To-do: edit Here are some Open Tasks : Copyedit: Improve: Animal, Zoology, Invertebrate, Vertebrate, Ethology, Photoperiodism, Tool use by animals, Omnivore Requests: Caminalcules Mammals: Grizzlar Bear, Jarkov Mammoth, Townsend's big-eared baty Invertebrates: Shingle urchin, Velvet mite, Fingernail clam Fishes: Pike eel, Spotted sucker, Berycidae, Trichonotidae Amphibians: Cave salamander, Nightfrog Stubs: Stud, Candling, Crawling, Growling, Hatchling, Litter, Crossbreed, Pack hunter, Personal grooming, Protobird, Spoor, Territorial marking, Worming Nominate and vote: Science collaboration of the month, Article Improvement Drive, WikiProject Animals Collaboration

Contents 1 differences in classification of superphyla 2 Cambrian 3 Nielsen phylogeny 4 Echinoderms (Taxobox)

[edit] differences in classification of superphyla

The taxobox in Animalia and the article lists the Ecdysozoa, Lophotrochozoa, and Platyzoa as separate superphyla at the same level as Deuterostomia The article and taxobox for Bilateria, to which all these groups belong, recognizes the first three of them as members of Protostomia, correlate to Deuterostomia, as does the classification in the talk for Animalia. There is also an article for Protostome; it & its taxobox similiarly group the three, as do the articles for Ecdysoza, Lophotrochozoa, and Platyzoa, all supported by both embryological and molecular data.

If these two scheme are in fact competitive analyses, surely the 2 hypotheses should at least be mentioned in all the relevant articles , instead of some silently adopting one and some the other. (I was taught protostomia, but that doesn't prove it correct) DGG 03:30, 4 November 2006 (UTC)

The classification of Ecdysozoa, Lophotrochozoa and Platyzoa as equal to Deuterostomia is relatively recent, and likely not fully accepted. Yes, the two schemes should be mentioned in the various articles, but we don't need a detailed discussion in every article; perhaps Protostome is the best place for that. -- Donald Albury 01:15, 5 November 2006 (UTC)

[edit] Cambrian

I don't know much about this at all, but this reference suggests these distinctions date back to the Cambrian era.

• http://cas.bellarmine.edu/tietjen/Ecology/early_animal_evolution.htm

There probably should be a paragraph concerning (postulated) evolutionary origins. MaxEnt 16:32, 29 June 2007 (UTC)

[edit] Nielsen phylogeny

I'm no expert in the phylogeny of animal phyla, but is the phylogeny given (cited to Nielsen) at all credible? It looks like a rather old, and now obsolete, version to me (particularly in presenting the Bryozoa and Entoprocta as forming a single clade which I believe was discarded quite some time ago, and uniting the annelida and arthropoda which was conventional wisdom until the late 20th century or so but which I'm not sure is widely held any more). Kingdon 14:32, 24 August 2007 (UTC)

Seems like no older than 2001, but it's troublesome by the fact that Nielsen proposed an alternative phylogeny about 2 years later, in order to solve the discrepancies between morphological data and molecular dito. Therefore Nielsen's phylogeny of 2001 should be considered obsolete. Said: Rursus ☻ 17:21, 4 November 2007 (UTC)

Newer articles based on molecular methods tend to agree in dividing the Bilateria into the three supergroups Lophotrocozoa, Ecdysozoa and Deuterostoma. The arthropods (or Panarthropoda) should definitely not be close to either the Annelida or the molluscs. Seven years is a very long time in phylogeny these days, and the tree should definitely be exchanged for a newer one. Jonht (talk) 16:38, 8 March 2008 (UTC)

[edit] Echinoderms (Taxobox)

20,000 species are quoted, whereas the Echinoderm page only says 7,000 species - which is correct? --Graminophile 11:08, 22 October 2007 (UTC)