Talk:Placozoa

How recently have they been observed?

The first sentence says they haven't been observed since 1896, but the rest of the text implies that they have been rather more extensively studied (even gene sequenced) and are "easily collected in tropical and subtropical latitudes around the world." For that reason, I'm tagging this article as contradictory. Deranged bulbasaur 16:08, 4 June 2007 (UTC)

It is the possible second species Treptoplax reptans that hasn't been seen since 1896, not Trichoplax adhaerens. Mgiganteus1 16:14, 4 June 2007 (UTC)

Also contradictory is the statement that dellaporta's article (reference 1)places them as basal to eumetazoa (a classification group which excludes porifera), where the article title indicates that they are basal to metazoa and actually reading the article confirms that the mitochondrial genome was considered to be between choanoflagellates and all metazoa including specifically porifera.71.111.48.55 03:33, 29 June 2007 (UTC)sms

Baker, Michael. Trichoplax, the simplest known animal, contains an estrogen-related receptor but no estrogen receptor: Implications for estrogen receptor evolution. Available from Nature Precedings (2008) —Preceding unsigned comment added by Cariaso (talk • contribs) 00:00, 14 August 2008 (UTC)

Rarely observed but easily collected?

The article states that have rarely been observed in their natural habitat, but then goes on to say that they are easily collected in tropical regions. Isn't this a bit of a contradiction??? "Trichoplax were discovered on the walls of a marine aquarium in the 1880s, and have rarely been observed in their natural habitat.[5] The full extent of their natural range is unknown, but they are easily collected in tropical and subtropical latitudes around the world." 129.170.66.218 (talk) 15:42, 7 September 2008 (UTC)

Sources

Might be useful --Philcha (talk) 14:40, 3 January 2009 (UTC)

• Placozoa - no longer a phylum of one

I found it more relevant at Trichoplax. May also be possible to use it here but I think more recent molecular work has been done. Martin (Smith609 – Talk) 17:46, 3 January 2009 (UTC)

This just came out-research putting them at the root of the tree *New Tree Of Life Divides All Lower Metazoans From Higher Animals, Molecular Research Confirms —Preceding unsigned comment added by 209.125.54.65 (talk) 18:05, 27 January 2009 (UTC)

Generic header

ALLEGATION -- Placozoa are 'long-lived larvae', of Calcareous Sponges, the 'next most primitive' animals. That fact explains the presence of Ca++ ions, in their interiors. And, Placozoa are transparent, and slightly concave on their undersides. Over millions of years, some Placozoa were picked up by wave actions, and learned to swim, with their Cilia... thereby becoming Ctenophore jellies, the 'next most advanced' animals. As a result of all of this, Placozoa, being a few millimeters across, are the same size, as sponge larvae. Note, too, that the fact that early Pre-Cambrian animals were so small, when the Sponges from which they evolved were macroscopic in size (<1m), is completely consistent, with this claim, that the first animals, evolved from 'long-lived larvae' stages of Sponges, not the larger adult forms. 66.235.26.150 (talk) 23:05, 10 March 2011 (UTC)

Frankly, no. This "hypothesis" is lacking for a number of reasons, the foremost being that it is based on a completely incorrect understanding of the basic principles of evolutionary biology. Ctenophores are not placozoans that learned to swim. Size is not particularly informative; this and this are closely related, while this is quite distant from both of them. And so on.

At any rate, Wikipedia does not include original research or unpublished theories. --Danger (talk) 04:07, 11 March 2011 (UTC)

Garbled Text

http://i.imgur.com/UO7VV.png I wasn't particularly certain if is was unanimously visible, but it concerned me that it existed at all. This seems to have appeared in a year-and-a-half-old edit, ("03:10, 4 January 2011‎ Smith609 (16,141 bytes) (-100) (Automate taxobox)",) when Smith609 seems to have 'automated' the "taxobox"? I'm uncertain how Wikipedia articles are operated, but I wanted to bring this to somebody's attention, since I didn't want to take matters into my own hands, and I was rather certain that it wasn't supposed to look like that. 71.83.238.195 (talk) 07:42, 25 July 2012 (UTC)

Eumetazoa

The page on Eumetazoa specifically excludes Placozoa from that sub-kingdom. This page, however, lists Placozoa under the Eumetazoa clade. I personally have no idea which is correct, but it ought consistent! If anyone knows which is correct, please change the incorrect page. Ge0nk (talk) 01:27, 12 September 2013 (UTC)

Likewise, the Animalia page lists Placozoa as a phylum of the sub-kingdom Parazoa, though it is mentioned to be considered paraphyletic on that page. As above, I lack the knowledge to make alterations for consistency, although I suspect there is no 'correct' classification as such, in which case footnotes addressing possible inconsistencies might be a good idea ? 82.231.41.7 (talk) 13:04, 3 November 2013 (UTC)

Remembering a frustrating discussion about much-derived relatives of the humble Placozoan (same kind of box/text inconsistency with the Accipitriformes in the German language version) I guess this has to do with different evolutionary rates of Wikipedia structures. The text can easily be adapted to acknowledge open questions and show the different possible taxonomies. The box is maintained separately by people who have the technical knowledge to think inside the box, but can't see why anybody would ever want to acknowledge that ambiguities exist. Stupid girl (talk) 00:19, 5 June 2014 (UTC)

Lead

Please, someone make a better lead than to say the Placozoa are 'invertebrate'.88.157.194.238 (talk) 17:53, 25 September 2014 (UTC)

Two species?

"Just two species of placozoans have ever been described, Trichoplax adhaerens and Treptoplax reptans."

http://www.ucmp.berkeley.edu/phyla/placozoa/placozoa.html http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=696106

Kitty 56 (talk) 16:03, 27 January 2015 (UTC)

As the UCMP page says, the initial find of T. reptans has never been repeated.

On the other hand, there is this recent report of a second species: [1] 128.91.20.12 (talk) 19:59, 12 September 2018 (UTC)

Until just recentlx, there were three genera, as the srticle states. However a new study including internal and external phylogeny and new species has just been released:

• doi:10.3389/fevo.2022.1016357

The article should be updated accordingly by a speciealist. Regards --Ernsts (talk) 16:40, 10 December 2022 (UTC)