Talk:Dipleurula

Translation

This article is translated from the German Wikipedia some links and vernacular names may be wrong. Jack 23:16, 22 January 2007 (UTC)

Retranslation and perhaps further revision?

As noted supra, this stub article originally (in 2007) was translated from dewiki (the German wikipedia). In September 2017, the German user de:Benutzer:TomCatX made this thorough revision of the dewiki article. The following is a rough translation from German of the article text (sources, weblinks, and categories uncounted), as TomCatX left it (and it still remains):

The Dipleurula is the abstracted basal form of the larvae of the Echinoderms (Echinodermata).

All the other recent forms of the Echinoderm larvae can be derived from the Dipleurula. Among them fall the Bipinnaria and the Brachiolaria of the sea-stars, the Auricularia of the sea-rollers and the Plutei of the sea-hedgehogs, and the sand stars. Also the Doliolaria of the Pelmatozoa (sea-lilies and feather stars) can be attributed to the same basic pattern, even if they do not have a mouth opening.

The Dipleurula is planktotrophic (feeds on plancton) and has a bilateral symmetric anatomy with a ventral (bellysided) 'mouthsack' (stomodeum?), which is surrounded by a band of cilia. The anus is ventrally placed, too.

(Links added. For the two unchanged sentences in the dewiki version, I just copied the (recent) translation by Jackhynes.)

I think that replacing the present text by this translation would be an improvement (of course leaving the nice illustration, and preferrably first resolving what TomCatX here meant by Mundbucht, which literally means 'mouth sac' or 'mouth bay', and in another context is translatable as 'stomodeum'). However, TomCatX also added the Dipleurula item in de:Lexikon der Biologie as a source. (I've added it to the stub, under External links) This indicates that perhaps the 'misunderstanding' TomCatX refers to in the edit summary largely is a confusion of different meanings of the term Dipleurula, more than a confusion between an hypothesis and an abstraction. In fact, the Lexikon der Biologie article refer to three meanings, of which the most common are

1) an intermediate larval phase (following the gastrulation but occurring before the more specialised phases) found in the development of most echinoderm larvae,

and

3) a phylogenetically proposed hypothetical common ancestor of "at least the echinoderms and the hemichordates" (with a number of the dipleurula properties).

("Sense 2" was denoted "rare", and could probably be ignored. I'm not providing an exact translation, since the Lexikon der Biologie article is copyrighted, but rather extract factual content from them.)

The sense 1, as described here, actually could be incorporated into Echinoderm#Larval_development. However, the forn source (provided by User:Stepp-Wulf) claims that also hemichordates have a dipleurula larval phase. This supports the relevance of a stand-alone article. The main relevance however, IMHO, relates to sense 3.

With some risk of WP:OR, my interpretation of the sense 3 description in the Lexikon der Biologie is the following: Embryonic/larval phases often reflect ancestral adult forms. In this case, since the dipleurula phase (or something sufficiently similar) is found in both echinoderms and hemichordates, their most recent common ancestor also should have had such a development phase, or have this as the final (adult) phase. Therefore, either this phylum, or an ancestor, should be a dipleurula like animal - reasonably also called a dipleurula. This hypothetical animal must be one common ancestor of at least all echinoderms and hemichordates, but could be an ancestor also of other related groups of recent animals, for two reasons:

a. The echinoderms and hemichordates together form the recent Ambulacraria, which generally is considered as a (monophyletic) clade. However, this phylogeny is not undisputed; some biologists have proposed evidence for rather grouping the hemichordates closer to some or all chordates than to the echinoderms. If they should be right, already the aforementioned most recent common ancestor, and thus a fortiori the dipleurula organism, also must be an ancestor to the chordates.

b. Even if ambulacraria indeed is monophyletic, the dipleurula may be a sufficiently much older organism than the ambulacraria crown group in order to be an ancestor also of chordates.

In fact, the reason I found this stub was that I saw a mention of dipleurula in connection with tunicate larvae.

However, if my interpretation is not borne out by better sources (or by editors with greater biological knowledge and skills in interpreting biological texts), it should not be employed in an article extension. JoergenB (talk) 21:41, 30 December 2019 (UTC)

Problem: Auricularia

This article has a wikiLink on the word auricularia, to link to the larval stage of the sea cucumber, but the link goes to a "genus of jelly fungi". It needs instead to point here: https://en.wikipedia.org/wiki/Sea_cucumber#Development ; but I don't know how to do that, so could someone more versed in the mechanics of wiki please make that repair? Thanks 2001:56A:F0E9:9B00:1177:ED93:CF7A:DA06 (talk) 05:41, 23 March 2022 (UTC)JustSomeWikiReader

this has been repaired with the last edit. Thanks for mentioning it! Marci68 (talk) 19:53, 13 May 2023 (UTC)

Complete revision

Hi, I completely revised the page and added links and references (some are old, but I have all the originals and studied them well). Accordingly, I replaced the two [[Wikipedia:Stub]] tags {{echinoderm-stub}} and {{developmental-biology-stub}}. Marci68 (talk) 15:28, 7 May 2023 (UTC)