Talk:Sea spider

Untitled

A picture of a sea spider would really go a long way to making the text of this article much clearer, but the only picture of a sea spider I've ever seen (which made this clear to me) is a drawing in Fingerman's Animal Diversity textbook, and the drawing is copyright-encumbered. If you've got access to an image of a sea spider that isn't so encumbered, please put it up here. --arkuat (talk) 06:28, 16 August 2005 (UTC)

most divergent of arthropods?

Take a look at a free summary from Science [1]:

Sea spiders do seem to be as primitive as they look. Unlike spider fangs, both chelifores and their nerves sprout from the cells that form the front most part of sea spiders' brains, the team reports 19 October in Nature. This supports the theory that sea spiders belong to their own ancient lineage that predates the origin of all other modern arthropods. It also suggests that all of today's other arthropods inherited their heads from a subsequent ancestor that gave up such up-front appendages.

Nature articles at [2] and [3]; editorial summary at [4]. kwami 07:57, 20 October 2005 (UTC)

• Indeed, and the page on Chelicerata does not list them as a member (citing those reasons), so this page should probably be edited to reflect that (it currently lists them as a member) —Preceding unsigned comment added by 210.215.140.180 (talk) 04:27, 27 January 2009 (UTC)

No coelom?

I read somewhere that the sea spiders don't have any coelom. Is this correct?

"Pycnogonids possessed a coelom at one point, but it was eventually lost through evolution". IronChris | (talk) 20:50, 22 August 2006 (UTC)

Pictures of sea spiders

Click here to see pictures of sea spiders

Do they or don't they?

The article contradicts itself: "Sea spiders do not swim but rather walk along the bottom with their stilt-like legs." Then in the next paragraph: "They crawl slowly along (although some do swim), feeding." I'm no expert, but both cannot be true. RandyKaelber 20:51, 22 September 2006 (UTC)

Fixed it. They apparently do both. Gerardw (talk) 22:23, 19 February 2008 (UTC)

Suspect video

According to Deep Sea News: Also interesting, and also noticed by Kevin, is an error occurs in the video. The announcer discusses giant sea spiders, while what is shown is a swimming crinoid. Accordingly, I'm going to take the link to video down. Gerardw (talk) 04:22, 20 February 2008 (UTC)

Classification

There's interesting information here: http://www.springerlink.com/content/w217212537272172/fulltext.html on sea spider classification. Perhaps it can be used to update the article. Jalwikip (talk) 10:40, 12 June 2009 (UTC)

References to small size of sea spiders vs lead

There are multiple references to details of pycnogonid anatomy explained by their supposed small size; e.g.:

“ Because of their small size and slender body and legs, no respiratory system is necessary, with gases moving by diffusion. ”

“ Pycnogonids are so small that each of their tiny muscles consists of only one single cell, surrounded by connective tissue. ”

However the lead says:

“ There are over 1300 known species, ranging in size from 1 to 10 millimetres (0.039 to 0.39 in) to over 90 cm (35 in) in some deep water species. Most are toward the smaller end of this range in relatively shallow depths, however, they can grow to be quite large in Antarctic waters. ”

(emphasis mine).

So there are large pycnogonids. I suspect that some of the explanation in the article can be only partially correct (i.e. good for smaller ones but not for large ones). Anyone knows how to solve this discrepancy? Good reviews on pycnogonid anatomy? --Cyclopia^talk 13:30, 17 August 2010 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Sea spider/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

This article could do with some more references, and internal links in the yet linkless section Reproduction and development. IronChris

Last edited at 17:51, 4 January 2007 (UTC). Substituted at 05:39, 30 April 2016 (UTC)

Error in illustration

The caption for the figure at the top of the Description section (copied here, right) belongs to a different illustration: clearly the list of marked items in the caption doesn't match the marks on the illustration.

Anatomy of a pycnogonid: A: head; B: thorax; C: abdomen 1: proboscis; 2: chelifores; 3: palps; 4: ovigers; 5: egg sacs; 6a–6d: four pairs of legs

• The referenced body divisions A, B, and C are not present on the illustration.
• The labelled leg segments L1–L4 are not discussed in the caption, but marks 6a–6d (legs) are not in the illustration.
• I believe that item 5, the egg sac in the caption, is not in fact what 5 in the illustration points to on the right side. The yellow cluster on the left side of the illustration, grasped in a minor leg, seems to be illustration's egg sac.
• The illustration has a marked item 7, but no 7 is discussed in the caption.

A great admirer of Sherlock Holmes, I deduce that there was a prior illustration for which the caption was written. Some hasty edit (possibly done because of copyright issues) failed to transfer the new caption along with a new illustration. The edit needs to be repaired.

As far as the remedy for the problem goes, my grandmother often said If enough is good, then too much must be better. I think that she would agree that two illustrations have to be better than one, and that both illustrations should be re-joined with their correct captions, and restored to the article – perhaps placed in widely separated locations, where the reader might wish to refer to vocabulary for strange body parts.

• Could someone please find the original illustration, and put it back?

• Could someone please take the current illustration and replace the caption with a caption that matches? (Perhaps from the original source.)

67.76.146.84 (talk) 06:46, 13 May 2017 (UTC)

Diverticula

OK, this may be obscure, but the link to diverticula leads to article about various medical pathologies. Diverticulum (mollusc), although specifically about about mollusc (mollusk) digestion, is more relevant as the same mechanism is in play here. Thus, I'm changing the link to Diverticulum (mollusc) with an eye to expanding the mollusc article to acknowledge that similar mechanisms are found elsewhere in the animal kingdom RATHER THAN to try to rewrite the medically oriented one to include sea-spider anatomy.

GeeBee60 (talk) 13:56, 17 March 2018 (UTC)

Do the smallest sea spiders have only one cell per muscle?

This is fascinating, if it is true. Could really do with a reference