Talk:Sea slug

dab?
Should this article be replaced with a disambiguation page? (Is it really notable as a broad-concept topic, or is it usually used as an ambiguous term for either nudibranchs or else sea hares or else..?)

The problem is that what sea slugs have in common is really only their superficial resemblance and the fact that they live in the sea; they're a paraphyletic grouping with more in common with other animals (that aren't sea slugs) than with each other. Since everything that uniquely defines them as a group is so superficial, there isn't much scope for writing an article about such a group. (So while it might be perfectly fine to have material on "gastropod reproduction", it doesn't make sense to have a detailed section on "sea slug reproduction". The best we could do is describe the reproduction of each class of sea slug separately, in which case we'd just be duplicating content from each class's own page, or else try to describe what is common to all, in which case we'd just be duplicating content of the gastropod page.)

And what about sea cucumbers? (According to oxford dictionary, the original "sea slugs" were not even in the same phylum. So the broader-concept may still be ambiguous too.)

Currently, there are no inline citations, and worse than that, the existing content is not even plausible. (For example, the reproduction section involves mantle cavities without acknowledging that this anatomic feature is not present at least in the first type of animal it claims to cover - nudibranchs. The section is obviously written in a manner specific to one kind of sea slug. In fact, some of the references listed are obviously are referring, ambiguously, to one class such as sea hares alone.)

By deliberately seeking out sources that refer to "sea slugs" rather than specific subclasses thereof, we're more often going to encounter sources which are simply using the ambiguous "sea slug" term to still refer to one particular subclass rather than the whole set. That is, we're biased towards the least clear sources. (Good-faith attempts to integrate such sources into the article are likely to produce confusion.)

If we are going to cover the broad-concept, then I think the focus should not be biological aspects like reproduction, but instead aspects like "significance to recreational scuba divers" (since divers tend to take an interest without distinguishing between) or "colour and toxicity" (since these tend more to be convergent).

Cesiumfrog (talk) 23:04, 21 January 2013 (UTC)


 * You make some very good points here. I will have to think about the idea of reducing this to a dab page, that might be less helpful than a short article as the subject is rather confusing. However this article is obviously not very good as it currently stands, even though it is better than it was a year ago. Invertzoo (talk) 21:39, 2 May 2014 (UTC)


 * Update: I decided you were right, and so I went ahead and reduced the article to a disambiguation page. Invertzoo (talk) 15:24, 13 May 2014 (UTC)

The following three messages are copied here from my talk page. Invertzoo (talk) 16:28, 14 May 2014 (UTC)


 * Greetings. If you intend to convert this into a disambiguation page, please fix all incoming links before making such a change. In my opinion, however, the concept of a "sea slug" is encyclopedic even if only to describe how unrelated species have historically come to be lumped together under this common name. Cheers! bd2412  T 04:33, 14 May 2014 (UTC)


 * You are right that I should have changed all the links first -- I forgot that, never having done this particular kind of change-over before. Do you mind if I copy your note from here onto the talk page for the article? And in reply to what you suggest, unfortunately it is not really feasible to trace historically how all the various species came to be lumped under the common name "Sea slug". That would require years of research in the older literature, and still one would be left with many questions. Invertzoo (talk) 13:37, 14 May 2014 (UTC)


 * Please feel free to copy my comment as needed. As to your concern about the feasbility of this article, I doubt that any article in Wikipedia comprehensively covers its subject. The bare outline here is the fact that there is a phrase, "sea slug", which is generally understood to encompass a number of species that are not closely related, but have certain common physical characteristics. The lay reader might well think that "sea slug" is merely the common name of a species, so it may well be useful to have an explanation of why that is not the case, even if the explanation does not cover the history by which each species came to be known as a sea slug. bd2412  T 14:17, 14 May 2014 (UTC)

Update
Today I have tried to improve the outline and shape of this article since it seems it is not gong to be reduced to a dab page after all. Of course it does indeed need a lot more references, but I was first trying to decide what should be included. I did add a bunch of images also, as will be obvious to anyone who looks at it. I still am not too happy with including the literature piece by P. H. Gosse, which seems to be sort of tacked on to the article. I would appreciate some help from other editors with fixing the article up some more. Invertzoo (talk) 21:26, 15 May 2014 (UTC)

The Gosse piece
I have removed the section entitled "Sounds" from this article and placed it in the article about nudibranchs -- that is a much better place for it. It is a very interesting quote, but as far as I know this observation has never been confirmed by any other person, despite many people keeping nudibranchs in aquariums. Please do not place the section back into this article; it is much better in the nudibranch article. I also improved the reference and improved the intro sentence for the long quote, as you can see below. Invertzoo (talk) 11:45, 25 July 2014 (UTC)

Apparent production of sound
In 1884, Philip Henry Gosse reported observations by "Professor Grant" (possibly Robert Edmond Grant?) that two species of nudibranchs emit sounds that are audible to humans.

"Two very elegant species of Sea-slug, viz., Eolis punctata [i.e. Facelina annulicornis], and Tritonia arborescens [i.e. Dendronotus frondosus], certainly produce audible sounds. Professor Grant, who first observed the interesting fact in some specimens of the latter which he was keeping in an aquarium, says of the sounds, that 'they resemble very much the clink of a steel wire on the side of the jar, one stroke only been given at a time, and repeated at intervals of a minute or two; when placed in a large basin of water the sound is much obscured, and is like that of a watch, one stroke being repeated, as before, at intervals. The sound is longest and oftenest repeated when the Tritonia are lively and moving about, and is not heard when they are cold and without any motion; in the dark I have not observed any light emitted at the time of the stroke; no globule of air escapes to the surface of the water, nor is any ripple produced on the surface at the instant of the stroke; the sound, when in a glass vessel, is mellow and distinct.' The Professor has kept these Tritonia alive in his room for a month, and during the whole period of their confinement they have continued to produce the sounds with very little diminution of their original intensity. In a small apartment they are audible at the distance of twelve feet. The sounds obviously proceed from the mouth of the animal; and at the instant of the stroke, we observe the lips suddenly separate, as if to allow the the water to rush into a small vacuum formed within. As these animals are hermaphrodites, requiring mutual impregnation, the sounds may possibly be a means of communication between them, or, if they are of an electric nature, they may be the means of defending from foreign enemies one of the most delicate, defenceless, and beautiful Gasteropods that inhabit the deep."