Liphistius, no venom!?

ornata

Arachnoknight
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hello

I know that the Liphistius genus is VERY old, about 200 million years, but may this be the reason for why they do not have any venom glans!?

Does this mean that the "first" spiders that evolved, did not use venom to kill their pray?

since other aracnids, like scorpion have been using venom since they began to walk on land, I think this is something to "think about":)
 

syndicate

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spiders of the family Uloboridae also do not posses venom glands.
 

lucanidae

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Mesothelids, of which the Liphistius belong to are known from the fossil record to be at least 300 million years old. They show many of the primitive features that the common ancestors of Mesothelids and Opisthothelae (true spiders and tarantulas) probably had. Yes, the most primitive spiders did not have venom. Just like Mesothelids do now, they used their chelicerae simply to grind prey to death. Behavior almost always precedes morphology in evolution. The common ancestor of true spiders and tarantulas gained venom after it had already split from the Mesothelids, this may have even been what caused the split!

Remember also that Amblypygids are the closest relatives to the spiders. At some point these two groups were the same thing! These animals did not have venom either, as evidenced by the fact that neither amblypygids nor primitive spiders (mesothelids) have venom.

In fact, if you go back far enough you have only two main groups of arachnids, the spider/amblypygid/uropygid etc group, and the scorpion/sulfugid/opilionid etc group. All of these were crawling on land and probably beginning to split into their modern day groups long before the use of venom for any of them.

Also, Uloborids lost their venom secondarily. At one point they did have it, but probably their small size made it more beneficial to stop wasting resources on venom.
 

ornata

Arachnoknight
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Mesothelids, of which the Liphistius belong to are known from the fossil record to be at least 300 million years old. They show many of the primitive features that the common ancestors of Mesothelids and Opisthothelae (true spiders and tarantulas) probably had. Yes, the most primitive spiders did not have venom. Just like Mesothelids do now, they used their chelicerae simply to grind prey to death. Behavior almost always precedes morphology in evolution. The common ancestor of true spiders and tarantulas gained venom after it had already split from the Mesothelids, this may have even been what caused the split!

Remember also that Amblypygids are the closest relatives to the spiders. At some point these two groups were the same thing! These animals did not have venom either, as evidenced by the fact that neither amblypygids nor primitive spiders (mesothelids) have venom.

In fact, if you go back far enough you have only two main groups of arachnids, the spider/amblypygid/uropygid etc group, and the scorpion/sulfugid/opilionid etc group. All of these were crawling on land and probably beginning to split into their modern day groups long before the use of venom for any of them.

Also, Uloborids lost their venom secondarily. At one point they did have it, but probably their small size made it more beneficial to stop wasting resources on venom.
thank you:)

I know that Mesothelids is a VERY old spider family,
but when it comes to the genus Liphistius, how old do you think this genus is?(maybe hard to answer)

To tell it like this, how long have the species within this family that exsist today, like the giant malasyan trapdoor spider, been around!?

They still have segemented abdomens and no venom glans,so it seems to me that the malasyan trapdoor spider(and all other species within this genus) must have been IDENTICAL when dinosaurs walked the earth, or even before!?

I also think that this has something to do with that they can be found in the country that have the worlds oldest tropical forests, dating back 70-100 million years!?:)

(sorry about the english)
 

Martin H.

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Hi,

I know that the Liphistius genus is VERY old, about 200 million years, but may this be the reason for why they do not have any venom glans!?
Rainer Foelix recently found the prove, that Liphistius spp. do possess venom glands! This information will be first printed in the next issue of the ARACHNE and a more detailed article in a future issue of the JOA or so.

all the best,
Martin
 

Venom

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Very nice! I can't wait to read all about it. :D Keep us posted.
 

Zoltan

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Hello Martin,

What about other liphistiids?

Edit: they have venom glands, ok, but do they actually secrete venom and can they actually use it?
 
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John Kanker

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Well if they have venom glans and venom ducts they why shoudn't they be able to secreate venom?
So if they can secreate venom what would the reason be why they can't use it even if only a small amount?
 

Zoltan

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Well if they have venom glans and venom ducts they why shoudn't they be able to secreate venom?
So if they can secreate venom what would the reason be why they can't use it even if only a small amount?
I probably should have formed my question better: do the venom glands have excretory canals? I've seen a drawing of a Liphistius chelicera where there is something that might be a venom gland, but there's no venom duct (hence my question). There's been a report about Liphistius malayanus possessing venom glands by Jezequel (1960); this wasn't supported, but rather disproved by Haupt's (2003) findings.
 

Zoltan

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It is not entirely clear which figure Chris Sainsbury refers to, but I do believe it is plate 3. figure 1. of

Bristowe, W. S. 1933a. The liphistiid spiders. With an appendix on their internal anatomy by J. Millot. Proceedings of the Zoological Society of London 103: 1016-1057.

Although the only Bristowe reference in your linked article is William S. Bristowe:- A Family of Living Fossil Spiders. - I was unable to find any such article.

The above mentioned figure is the one I was referring to in my previous post, but it's only a drawing, and when compared to Haupt's image (Haupt, 2003 f. 5. B), contradiction arises.

Anyway, the more interesting aspect of all this is: how many species did Foelix study? Do all Liphistius species lack venom glands and/or venom ducts? Haupt claims there are no openings of glands on the chelicerae (Haupt, 2003: 6; figs. 6. A-B), which would support the claim that there are no venom ducts. Also, Millot in Bristowe, 1933 does state that he hasn't found venom glands in Heptathela kimurai (although he has only examined one specimen), this is also supported by Haupt. If some or all Liphistius do indeed possess venom glands/ducts but other liphistiid genera don't, that would be extremely interesting!

I should probably just shut up and wait for Foelix's article?!

Reference:
Haupt, J. 2003. The Mesothelae -- a monograph of an exceptional group of spiders (Aaneae: Mesothelae): (Morphology, behaviour, ecology, taxonomy, distribution and phylogeny). Zoologica 154: 1-102.
 

MaartenSFS

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No, keep talking - it's interesting. I was hunting for these in China. Now I will mount a full expedition when I go back! Keep the information coming!
 

Zoltan

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The article Martin was referring to is published in the the latest issue of The Journal of Arachnology:

Foelix, R. & B. Erb. 2010. Mesothelae have venom glands. Journal of Arachnology 38(3): 596-598.

Abstract. Although venom glands were described for the Mesothelae many years ago (Bristowe & Millot 1933), a more recent monograph (Haupt 2003) denied the existence of such glands in the Mesothelae. Our morphological studies of nine different species of Liphistius demonstrated the presence of venom gland openings on the cheliceral fangs in all of these species. Also, we observed a small venom gland in the anterior portion of the cheliceral basal segment. The possibility that venom glands may be lacking in adult males is discussed. The presence of venom glands in the Mesothelae indicates that this is a plesiomorphic character of all Araneae.

I haven't had a chance to read it yet.
 
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Lorum

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I haven't had a chance to read it yet.
It would be great if you could get it and share it, hehe. Well, just in case you get it, I would be glad if you could send it to me.

That's very interesting... discoveries like that can actually change things we know about systematics of spiders.
 

Zoltan

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It would be great if you could get it and share it, hehe. Well, just in case you get it, I would be glad if you could send it to me.

That's very interesting... discoveries like that can actually change things we know about systematics of spiders.
I got it yesterday, I'll mail a copy to you shortly. If anyone else wants it, send me a PM with an e-mail address I can send to.
 
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