Talk:Eumetazoa

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Contents 1 Mergers 2 Possibly just protostome could be merged into deuterostome. 3 Eumetazoa not a clade? 4 characteristics of Eumetazoa 5 Metazoa redirect to Animal

[edit] Mergers

Redirecting Eumetazoa to animal is not completely correct. It would make more sense to collect the stub articles on the superphyla in Eumetazoa. This would clarify (disambiguate) the information without forcing the user to go to wikispecies to puzzle it out. TheLimbicOne 01:11, 4 January 2006 (UTC)

If it makes sense to redirect protostome to Eumetazoa, why doesn't it make sense to redirect Eumetazoa to animal? The two groups are not identical, but they are close, whereas groups like deuterostomes are very different in composition. There is a lot to say about each superphylum on their own, and they are used in most classifications, whereas Eumetazoa isn't. I think the proposed moves are very bad ideas. Josh

I think the proposed mergers would be a bad idea. One, I don't understand what the benefit would be. Two, redirecting clade A to clade B will just create confusion -- non-experts will wonder why they ended up at B when they looked for A, and once the reader figures out the reason for the surprising redirect, he/she still has to hunt for the relevant information in an article that's mainly about something else. --Chl 01:56, 4 January 2006 (UTC)

Allow me to clarify. Eumetazoa is a subregnum (subgroup) of regnum Animilia (Metazoa). Animilia includes Eumetazoa. Eumetazoa includes the following superphyla: Radiata, Bilateria: Protostomia (protostomes), and Bilateria: Deuterostomia (deuterostomes). Eumetazoa used to link to animal. This implies that Wikipedia has no information on Eumetazoa, which is not true. Either the page for Eumetazoa should be a disabig page (frown) or Eumetazoa can include information on it's member groups with a link to animal (it's parent group).

"...redirect clade A to clade B..." and people will wonder, "why did I get directed here?" This page used to do exactly that, by redirecting to animal. This is exactly what I wish to correct.

"Ther is a lot to say..." Then please expand the current stubs. I agree that there's a lot of info for those articles, but I don't have it to add. If a section, deuterostomes for example, becomes large later on, we can split it out later. Right now, it does nobody any good to have tiny bits of information scattered about.

"Why...doesn't it make sense to redirect..." I'm not proposing redirects, I'm proposing a merger of stub articles into a coherent parent article.

(note: I've invited Chl and Josh to consider this clarification.) TheLimbicOne(talk) 02:48, 4 January 2006 (UTC)

According to the Columbia Encyclopedia (which may be out of date or whatever), this group includes all animals except sponges and Mezozoa (which I'd never heard of before). We definitely don't want it to redirect to Animal for that reason; someone that wants a definition of Eumetazoa and types it into Wikipedia will get the false impression that Eumetazoa=animalia.

As long as the opening line of a combined article had all the relevant terms in bold, i.e. "Eumetazoa is a subkingdom of Animals that includes the Radiata and Bilateria; all animals except sponges and mezozoans are Eumetazoans," I think that would be okay, in terms of not confusing the reader too much.

The best solution is probably not to merge, though. I think this article should read "Eumetazoa is a subkingdom of Animals that includes the Radiata and Bilateria; all animals except sponges and mezozoans are Eumetazoans." and then describe what the Radiata and Bilateria have in common. I think it's okay if this article is short. Dave (talk) 08:33, 4 January 2006 (UTC)

I'm opposed to the proposal to merge deuterostomes and protostomes into eumetazoa. These are very important clades of animals, and I think it would be harmful to merge them into eumetazoa. There is nothing wrong with short articles. These are not sub-stubs. It would be better to work on expanding these articles. I think every important clade should have it's own article. -- Dalbury^(Talk) 13:20, 4 January 2006 (UTC)

I'm going to go a bit further: both the Tree of Life Web Project [1] and the University of California, Berkely Museum of Paleontolgy web site [2] classify Deuterostomia as one of some ten clades that make up Bilateria. In these classifications, there is no Protostomia, and the protostomes are simply all the clades in Bilateria that are not part of Deuterostomia. Both of these sites have copious references, are written by experts in the field, and are much better representations of the current understanding of phylogeny than are other encyclopedias. These sites are good secondary sources, while encyclopias are tertiary sources. I think these two sites are a good guide as to which clades should have there own articles. With a little reasearch, all of the clades can be made into adequate articlea that stand on their own. -- Dalbury^(Talk) 13:50, 4 January 2006 (UTC)

Okay, I was basing my opinion on the info at Wikispecies (see link on article page). Is that info correct? TheLimbicOne(talk) 14:27, 4 January 2006 (UTC)

I see no references for that page in Wikispecies. That certainly makes it a poor candidate as a source for Wikipedia. The clade diagram on the page differs in details from the sources I look at, but that is not necessarily a major concern. Tolweb often gives alternative clade diagrams when there is not broad agreement on classification, and we certainly owe it to the readers to indicate that there are differences among authorities, and that the whole classification scheme is changing as more information becomes available and is reinterpreted. I also fail to see why the way Wikispecies presents information should constrain how Wikipedia does so. -- Dalbury^(Talk) 17:56, 4 January 2006 (UTC)

High-level classification is variable. The version wikispecies uses isn't necessarily wrong, but it isn't necessarily standard and it isn't the whole story. Radiata, Protostomia and Deuterostomia are commonly used, whereas I've seen systems that don't use Eumetazoa. Whatever you were planning to leave behind after the merger - if not redirects, an explanatory note or something - I still think would be more appropriate on Eumetazoa than on those other pages. Josh

I was going to redirect them here and put their content here after a rewrite and polishing. However, I think it's obvious that a large group of wikepedians feel this shouldn't happen. No problem. It wasn't my original intention; however, I'm happy that I stirred up enough interest to get this article on eumetazoa going and that's good enough. --TheLimbicOne(talk) 23:46, 4 January 2006 (UTC)

[edit] Possibly just protostome could be merged into deuterostome.

If we don't merge (as I see I'm in the minority), can we leave the stub article here with a link to animal, protostome, and deuterostome instead of blindly redirecting to animal? Additionaly, I'd like to re-write the articles on protostome and deuterostome. The articles currently look like they were copied out of a book that discussed them in a single article. For instance, the protostome article talks as much about deuterostomes as protostomes. That was the whole reason I wanted to merge in the first place. The two subjects complement each other well enough to be in the same article and I couldn't decide what a combined article should be named. I've started new subject to discuss this idea. TheLimbicOne(talk) 14:27, 4 January 2006 (UTC)

See the subject mergers for more background discussion relating to this idea. Any comments on this option? TheLimbicOne(talk) 14:27, 4 January 2006 (UTC)

The groups complement each other, but they are separate clades, with separate characteristics and subgroups. The protostome article doesn't talk about modern deuterostomes, although it does have a lot of discussion about how deuterostomy was the ancestral condition. This could use a reference, and maybe should be moved up to Bilateria or animal? Josh

The problem is that the clade Deuterostomia and the clades known collectively as Protostomia are a fundamental division, like Vertebrate and Invertebrate. I would compare merging Deuterostomes into Protostomes to merging Vertebrate into Invertebrate. -- Dalbury^(Talk) 18:06, 4 January 2006 (UTC)

"to merging vertebrate and invertebrate..." or grouping apples and oranges into one article on fruit? Yes, protostomes and deutereostomes are complete opposites, but since all we have in their articles is a definition (and WP is not a dictionary) and a discussion of their common evolution, why not group the information into one article at the next higher level. --TheLimbicOne(talk) 00:54, 7 January 2006 (UTC)

Deuterostomia is a major taxon. On the other hand, protostomes may not be a taxon, as such, but simply a collection of Bilaterian taxa that are not deuterostomes, just as invertebrates are not a taxon, but a collection of all animals that are not vertebrates. As a taxon, or clade, Deuterostomia should have it's own article. I see the hierarchy of articles as:

1. Animals at the top
2. Sponges and Eumetazoa under Animals
3. Radiata and Bilateria under Eumetazoa
4. Deuterostome, Ecdysozoa, Lophotrochozoa and several smaller taxa under Bilateria.

Protostome covers everything under Bilateria except for Deuterostome. The Protostome article could be expanded to include the history of use of the term, which has shifted as the relationships of phyla have been better understood. If Protostome is merged into anything, it should be the Bilateria article. I think it is just a matter of some time and effort to build up all of these articles to well beyond stub status. -- Dalbury^(Talk)

Thank you. That removed any lingering doubt I had about removing the merge tags. Your explanation is so logical, I'm only left with one thing to say, "I stand corrected." --TheLimbicOne(talk) 04:56, 7 January 2006 (UTC)

Now I have to find time to work on these articles. I should wait a little bit, anyway, to see what other opinions are around on how to organize the 'tree'. -- Dalbury^(Talk) 11:47, 7 January 2006 (UTC)

It's really not up to us to "organize the tree". There is no single tree: each piece of research results in a different tree. We don't have the expertise to judge between the alternatives: all we can do is present them. For the taxoboxes we try to pick an authoritative and well-respected published synthesis.

Since above-phylum-level taxonomy is currently in a period of flux, it's important not to "take a view" ourselves but to present the alternatives. In particular, we shouldn't start merging articles even if it looks like certain taxa are not clades. First, we may be wrong. Second, many names continue to be widely used even though known to be paraphyletic or polyphyletic, e.g. protists, reptiles, algae, fish, sharks. And third, the article gives us a place to record the history of the taxon and its study. So no merges, please. Gdr 00:35, 8 January 2006 (UTC)

As luck would have it I've stayed away for a week and saved myself from getting in the middle of this. I'd like to say that I agree with the ideas of not trying to describe the taxonomic tree - as a human construct its in flux, and will continue to be until the human race gets comfortable with not being able to fit everything into little boxes. I think its most important for each of these taxons to describe the criteria for belonging to the taxon and listing the subtaxa generally accepted, and those disputed, as subordinates. Mattopaedia 01:43, 8 January 2006 (UTC)

[edit] Eumetazoa not a clade?

The article says "Most other classification schemes do not include a subkingdom Eumetazoa. Cladistic systems do not recognize Eumetazoa because it does not form a monophyletic clade." Whether or not they consider it a subkingdom, many recent papers and classifications refer to the clade Eumetazoa as comprising those animals (metazoans) that have tissues and a gastrula stage of development. This excludes sponges but includes Cnidarians and Bilaterians. More obscure groups such as mesozoans and Trichoplax are more problematic, but either fit into that clade or don't. Cephal-odd 01:27, 1 October 2006 (UTC)

Saying that Eumetazoa comprises those animals (metazoans) that have tissues and a gastrula stage of development makes it a 'grade', not a 'clade'. A clade is by definition a group of organisms consisting of a single common ancestor and all the descendants of that ancestor. (see Clade. The Tree of Life project does not include Eumetazoa in its cladograms, and the University of California, Berkeley Museum of Paleontology also does not use Eumetazoa in its cladograms. -- Donald Albury 17:05, 1 October 2006 (UTC)

Thanks for the feedback. You're right that those characters can't define a clade, but they can be synapomorphies that diagnose a clade. Presumably tissues and a gastrula stage were characters of the last common ancestor of all eumetazoans.

Actually, both the UCMP and the Tree of Life project do depict eumetazoans as a clade within their trees; they just don't label that node. The cladogram on the TOL page for Animals has a polytomy that clearly constitutes a clade that excludes a (paraphyletic) Porifera. Likewise, the cladogram on UCMP's Metazoa: Sytematics page shows a clade uniting Bilateria, Cnidaria, & Placozoa nested within a larger clade that includes Ctenophora. This later clade too is unlabeled, but it clearly represents Eumetazoa, since it excludes the (again paraphyletic) Porifera.

It would be a mistake to assume that a node isn't a clade just because it isn't labeled. For example, further down the hierarchy, under UCMP's Vertebrates: Systematics, there is no label on the cladogram for Gnathostomata. However, the groups from Placodermi clockwise to Tetrapoda clearly constitute a clade in this cladogram, and the gnathostomes are even mentioned in the text below.

Here's another example of a university website that does explicitly mention Eumetazoa as a clade, and even lists a few synapomorphies: <http://www.biology.ualberta.ca/courses.hp/zool250/Clades/clade02-Metazoa.htm>

Going back to the primary literature, we can find several papers that refer to Eumetazoa as a clade. Here are two of them:

• Peterson, Kevin J., and Nicholas J. Butterfield. 2005. Origin of the Eumetazoa: Testing ecological predictions of molecular clocks against the Proterozoic fossil record. Proceedings of the National Academy of Sciences USA 102(27): 9547–9552.
• Jager, Muriel et al.. 2006. Expansion of the SOX gene family predated the emergence of the Bilateria. Molecular Phylogenetics & Evolution 39: 468-477.

Cheers, Cephal-odd 01:02, 2 October 2006 (UTC)

If you have the sources, change the article and cite the sources. I haven't found anything that explicitly says Eumetazoa isn't a clade. -- Donald Albury 13:22, 2 October 2006 (UTC)

OK; I'll pull together a few more sources and make the change shortly.

Cephal-odd 04:07, 6 October 2006 (UTC)

[edit] characteristics of Eumetazoa

I removed the mention of organs formed by germ layers, because as I understand it, only those animals with three germ layers (triploblasts) have true organs. Cephal-odd 04:55, 19 October 2006 (UTC)

I'm not sure how to do it, but someone could add a link to the chinese article on this. 65.78.17.194 01:48, 29 October 2006 (UTC)

[edit] Metazoa redirect to Animal

A wikipedian confused the terms Metazoa and Eumetazoa, and created a page for Metazoa describing the taxon Eumetazoa. Here is the information that was found on that page, if there is anything here that is not currently on this page, by all means use it.

• Metazoa usually refers to the animals with numerous cells which are arranged in layers or groups resulting in the formation of organs, fully differentiated tissues, including nerves and muscles. Different cells here can follow different lines of specialization to perform various functions. Characteristic of metazoa is the process of embryonic development by which the fertilized egg passes through a series of changes culminating in the formation of the adult. This includes all the animal phyla except the sponges, Trichoplax, and certain parasites. In older texts, Metazoa is often taken to be synonymous with our Animalia, excluding only the protozoa. It may be formalized as a subkingdom, but its treatment varies considerably. Metazoa are distinguished from other Animalia in that they can perform apoptosis. This is a biological recognition that cell differentation is essential to these organisms.

Werothegreat 17:41, 17 March 2007 (UTC)