Talk:Horseshoe crab

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This article should be merged with the Limulus Polyphemus article. -- Derek Ross

Contents

[edit] Horseshoecrabs dont have cancer?

This needed a citation. Taking into acount that this is __very__ umplausible I deleted the information. If there isnt a citation i dont think this information should be there... hi i am cool

[edit] Xiphosura versus Merostomata

Although the name Merostomata inertially persists in some textbooks, it should be discarded as a paraphyletic group in favor of Xiphosura which is a monophyletic group. I guess the article as conceived is completely disconnected with the other Chelicerata. Mention should be made to the fossil Xiphosura which had much more diversity than the present day relics. A little morphology would be useful as well.Vae victis 08:19, 10 April 2006 (UTC)

Is there any reason the taxonomic information was removed? --Mperkins 05:10, 12 Dec 2003 (UTC)

I reverted to the version with better English grammar, fewer quotes from other sources, and a taxobox. RickK 05:19, 12 Dec 2003 (UTC)

User:Khym Chanur had put 'White-crowned Wheatear' (a bird) at the top of the taxobox. Grrr. Salsa Shark 05:22, 12 Dec 2003 (UTC)
I doubt if it was vandalism, probably a copy and paste which he neglected to change. RickK 05:26, 12 Dec 2003 (UTC)
Oops; yes, it was a copy-and-paste error. Sorry. -- Khym Chanur

The animals can be returned to water after extraction of a portion of their blood (except in Massachusetts)

... What happens to them in Massachusetts? The crabs aren't strong enough to survive? They extract all the blood? They'll explode if they're returned to the sea? You've got my curiosity going, and I need to know! --194.247.44.210 16:33, 13 Jul 2004 (UTC)

No, the problem isn't with zombie/vampiric/exploding crabs. Instead, there appears to be regulations in Massachusetts that state that horseshoe crabs must be destroyed, at least according to this article on threats to horseshoe crabs. It would appear that these regulations are due to concerns over the amount of shellfish that are consumed by the crabs. --pjf 03:37, 2 Nov 2004 (UTC)
Good link. :) func(talk) 03:52, 2 Nov 2004 (UTC)

[edit] Gills vs Book Lungs

Xiphosura do not have lungs. They have only book gills which are homologous with the book lungs of the terrestrial, air breathing Chelicerata. Vae victis 08:22, 10 April 2006 (UTC)

The current text in the article states that the horseshoe crabs have gills. However, the picture mentions book lungs, and the text on book lungs mention horseshoe crabs specifically.

The text on this page, as well as on HorseShoeCrab.org suggests that horseshoe crabs don't have gills at all, and only possess book lungs, allowing them to breathe in the water, and also to remain out of the water for a short period of time while the lungs remain moist. The horseshoecrab.org section on anatomy actually calls these book gills, but the structure and operation appears to be the same.

I'll update the article based upon this, and to hopefully resolve the 'lungs vs gills' issues.

I'd love to see this cleared up, too. Unfortunately, the sources cited above actually do conflict with one another. Horseshoecrab.org refers only to "book gills", and the other page (from a local school district?) refers only to "book lungs." I have heard these membranes called "book gills" in lectures by several different scientists. For example, the Cape Cod Museum of Natural History held a conference on horseshoe crabs and their conservation in 2003 with several different speakers, and I remember hearing references to book gills there. Because Horseshoecrab.org seems the more scientific of the two sites cited above, I would prefer to see them only referred to as "book gills" and not as "book lungs." I agree with Vae Victis that they do not have lungs. Please do not update the article to put lungs back in unless you have a research article to cite for this. Peter 01:12, 2 March 2007 (UTC)

[edit] 4 species? What are the other 3?

This article has the statement: "In 1995, the nonprofit Ecological Research and Development Group (ERDG) was founded with the aim of preserving the four remaining species of horseshoe crab." Checking ERDG's website shows that it has that same statement, but only names a single species, Limulus polyphemus. What are the other 3 species?

Lyall Anderson lists three "genera [sic]":

  • Limulus polyphemus (Atlantic)
  • Carcinoscorpius rotunda (Indian)
  • Tachypleus gigas (Singapore)

Tree of Life has a taxonomy, with 2 citations, of extinct and extant horseshoe crabs, adding Tachypleus tridentatus to the list.

I'm not willing to rely solely on the Web for this, so I'll record this info here. It would make the article less confusing if we could list out all the genera and species.

--Fred 20:39, 30 Apr 2005 (UTC)

It could just be a "taxonomic problem". This site, http://www.thedarwinpapers.com/oldsite/number5/darwin5.htm , mentions that there are "There are three to five species, depending on which taxonomic system is being used". func(talk) 17:47, 2 May 2005 (UTC)
Whoops! Sorry, the above link is to a "creationist" website. The quote, however, comes from a book Invitation to Biology by Helena Curtis, (I think?). OK, the web is not always the best place to look things up. ;-) func(talk) 17:54, 2 May 2005 (UTC)
I've tried to clear this up with the new "Closely related species" section.Peter 16:16, 2 March 2007 (UTC)

[edit] Endangered species or not?

The first paragraph states that Tachypleus tridentatus is endangered, yet later on there is a sentence saying "No living species of horseshoe crab is endangered yet". Can someone clear this up? (this is not my field). --Blainster 20:00, 2 August 2005 (UTC)

Well, I looked for Tachypleus tridentatus on the IUCN Red List and it was a hit. I've changed the sentence to read 'Limilus polyphemus' instead of 'no living species'. Eeblefish 01:23, 30 March 2006 (UTC)

I created the Closely related species section and then found this section of the discussion. So I checked all four species against the IUCN Red List. All three Indo-Pacific species are listed as DD for Data Deficient. Limulus polyphemus is listed as E for Evaluated. No species is listed as EN for Endangered. lists the IUCN categories used in all four cases. Peter 00:40, 2 March 2007 (UTC)

[edit] What about Horsheshoe crab ocular regeneration

<someone please explain what is known about this> —The preceding unsigned comment was added by 207.179.68.164 (talk • contribs) .

[edit] Cleanup?

This article doesn't look like it needs a cleanup tag anymore; can someome explain why it's still there? It seems to me that the comments left by the person who put the tag up (intro too long, pictures too big) have been corrected. If no one has any objection, I think it can be removed. IronChris | (talk) 22:34, 7 May 2006 (UTC)

Recommend moving [1] to the Triops page, it appears to be a large variety of that instead of a horseshoe crab. 64.212.128.3 16:24, 12 November 2007 (UTC)

[edit] Life span contradiction

In the physical description section, the lifespan is listed first as "Horseshoe crabs can live for sixteen to nineteen years" and then later on it is said that, "They reach sexual maturity in approximately eleven years and may live another 10-14 years beyond that", which equates to 21-24 years. This is a bit of a contradiction and should probably be resolved or explained. --gwax UN (say hi) 18:22, 12 May 2006 (UTC)

[edit] "Foster and Smith, 2004" reference

In the introductory paragraph, there is a reference to "(Foster and Smith, 2004)." Could someone clarify that reference and include it in either the references or notes section? Thanks. User:Ceyockey (talk to me) 01:59, 15 May 2006 (UTC)

I have decided to remove this line altogether. It almost appears to condone keeping horseshoe crabs in captivity. And I agree that all citations should use wikipedia format.
I have changed the Leschen et al. link to a reference with a link to start to correct this problem. The next line quotes "Sturtevant" on horseshoe crab development. Google searches reveal that Dr. Patty Sturtevant has written several papers on horseshoe crabs, but I can't find the one that has this quote. Can anyone help identify this reference more specifically? Peter 16:36, 2 March 2007 (UTC)

[edit] Picture Synopsis

"When encountering a horseshoe crab in this position, one should "just flip 'em" and turn the crabs back over, unless they are dead, like this one is." I just had to say how much I love this. That's all. Experia 02:18, 15 August 2006 (UTC)

Made me laugh out loud first time I saw it. Still funny. Kuru talk 02:58, 15 August 2006 (UTC)

[edit] Sense Organ

"they have a small sense organ on the triangular area"...

Is it known what kind of sense it is? Smell, touch etc?

Greenaum 81.101.58.131 03:09, 29 August 2006 (UTC)

This question remains unanswered, over a year later.

Sojambi Pinola (talk) 17:56, 23 December 2007 (UTC)

[edit] Picture Description

The phrase "Pair of Horseshoe Crabs" should probably be changed. There are more than 2 crabs in the picture (unless it's the same 2 crabs in different poses, which may be the case). Jwgloverii 01:54, 9 March 2007 (UTC)

[edit] Horseshoe crab's blood plasma can cure a stroke

I remember viewing a program on some educational channel such as Discovery Channel that the blood plasma from a horseshoe crab can be separated out and (perhaps directly) used to treat a stroke victim. They said that if used within one hour after the stroke, it can completely reverse it and return the person to full motor function. I do not know how it happens, and a Google search proves difficult to find information on it (keywords:horseshoe+crab+plasma+stroke). This would seem to be something very useful and important, as the Wikipedia page on stroke says that it is the 3rd leading cause of death in the US.

The usefulness of it after that initial hour was said to diminish, but could still help.

If anyone can find corroborating references for any of this, that would be great.

199.46.198.234 23:03, 26 March 2007 (UTC)Jesse, Boston, MA

[edit] Eye research milestone section

I thought the section on eye research milestones was overkill. Maybe it's appropriate somewhere else, but I don't think it's appropriate for the main horseshoe crab article. I've reproduced it here:

.==Horseshoe Crab Vision Research Milestones==

1782 The cornea of Limulus eyes is first examined.

1883 Scientists describe the median eyes — each has a single lens and is a simple eye.

1890 Scientists investigate the anatomy of the lateral eyes (a complex eye composed of thousands of small hexagonal eyes called ommatidia — like in a honeybee).

1928 Dr. H. Keffer Hartline studies electrical impulses in the horseshoe crab optic nerve.

1932 The eye of Limulus is the first in which electrical responses are recorded from a single visual receptor.

1960 Scientists identify the visual pigment in Limulus eye to be rhodopsin. Rhodopsin: a light-sensitive protein in the retina that helps trigger nerve impulses between the optic nerve and the brain. Click here for more information on rhodopsin.

1967 Nobel prize is awarded to Dr. Hartline for research on vision in horseshoe crabs.

1971 Research studies reveal that a horseshoe crab's eyes are one million times more sensitive to light at night.

1977 Scientists discover that the sensitivity to light of the horseshoe crab's retina to light is regulated by an internal clock.

1980 Studies identify a circadian clock in the horseshoe crab's brain that enhances night vision.

1981 It is found that the simple eyes (median ocellus) of the horseshoe crab function as UV receptors, sending signals to the lateral eyes. Changes in UV light intensity provide the cue to turn off lateral inhibition, enabling horseshoe crabs to see better at night.

1982 Dr. Robert Barlow and colleagues discover vision plays a role in mating behavior. The circadian clock influences perception of contrast and form, and helps male horseshoe crabs detect potential mates.

1997 Dr. Barlow designs a "CrabCam" to investigate underwater vision in horseshoe crabs.

2001 A computer model of the lateral eye is developed by Dr. Barlow to understand how horseshoe crabs find their mates in varying light conditions. --Rschmertz 02:06, 30 April 2007 (UTC)

[edit] Scientific Name

The article lists the names limulus polyphemus and limulus cyclops, both of which seem to suggest that the creature has only one eye. However, it is then mentioned that it has four! I'm not suggesting that either of these facts are incorrect, but it is an interesting incongruity. Does anyone know why? --joeyo 04:47, 2 May 2007 (UTC)

[edit] WikiProject Pharmacology

This arthropod is cited as a homeopathic remedy by Virtual Health Library

[edit] Delicious?

Has anyone tried to eat one? Should a section on consumption be added? --NEMT 04:41, 10 June 2007 (UTC)

Having never even seen a live Horseshoe crab, I question my knowledge on this, but google tells me that they are edible, but certain bits of them can cause irritation. See http://www.ncbi.nlm.nih.gov/pubmed/11321949 --79.66.83.144 (talk) 18:52, 20 April 2008 (UTC)

[edit] Northern Atlantic coast of NORTH AMERICA

Is this accurate? Delaware is not even close to the nothern Atlantic coast of North America, it's more southern Atlantic coast of North America. (consider Labrador, Greenland) Or is this statement US centric and biased against true geography? 70.51.10.203 (talk) 06:24, 29 November 2007 (UTC)