Most vemonous true spider

I have been watching a few specials on tv and they seem to keep going back from the brazilian wandering spider to the sydney black funnel web spider.... I did some prelim searching and couldnt find anything concrete. What do you guys think? Now I'm going for straight up toxicity not environment etc.

Chaoshybrid6, From what I've gathered in bits and pieces thus far, my money would have to be on Sicarius sp(?) in terms of sheer drop for drop toxicity.

Terry

I was under the impression that the brazilian wandering spider was in the genus Phoneutria and the funnel web is in Atrax. Are you saying neither of these are the most venomous?

I agree the effects of its venom are horrible, its like a brown recluse bite x5 or worse, but there have been little to none recorded bites so its hard to say. Although the venom of this spider has been tested on animals (rabbits mice ect...) and studies indicate that the venom can cause massive local tissue destruction and that serious internal haemorrhage can and will develop. Butt if Im not mistaken arnt Phoneutria sp. true spiders.. they much more deadly....

"True spiders" often refer to the suborder Araneomorphae, so that rules out Atrax robustus (the genus Atrax is in the suborder Mygalomorphae, primitive spiders).

ErikWestblom said:

"True spiders" often refer to the suborder Araneomorphae, so that rules out Atrax robustus (the genus Atrax is in the suborder Mygalomorphae, primitive spiders).

Click to expand...

Damn,your good!

Well if they arent tarantulas and they arent true spiders then which forum do i post in? I assumed this one cause of the 'other arachnids'

the issue of the Atrox, and the Phoneutria have been covered in depth in this section ( it is the right forum) but there are many viarables before you can get a concreat answer

Such as:
do you seek the most potent per msg of venom?
Do you search the one that is responsible for the most deaths?
the one that injects the most?

While many spiders can be very detramental to ones health there is many reasons its not considered the most deadly, or deadly at all due to its inability to bite, chance to bite being so low refusal to bite. or no documented cases for comparison,

yawn....

seems like we're never more than 2 weeks away from another "most venmous" true spider thread...google it...Sicarius will pop up eventually

chaoshybrid6 said:

Well if they arent tarantulas and they arent true spiders then which forum do i post in? I assumed this one cause of the 'other arachnids'

Click to expand...

well, you excluded it automaticaly by calling your thread "most venomous true spider". This would still be the right forum for the Atrax robustus, but the title of your thread means this species does not belong in this thread, that's all.

Martin

tarcan said:

well, you excluded it automaticaly by calling your thread "most venomous true spider". This would still be the right forum for the Atrax robustus, but the title of your thread means this species does not belong in this thread, that's all.

Martin

Click to expand...

+1 Though the Atrax is not a tarantula (still a mygalomorph, though), it's neither a true spider, either.

By the title I would say a Sicarius or a Phoneutria. What does it matter which is more venomous anyway in a "my spider is deadlier than your spider" contest anyway? You'll need quick medical attention for either species.

It wasnt asked to say mines more dangerous than yours, it was asked because I've been seeing many different answers by big sources (animal planet, discovery, nat geo) etc.. and just wanted to see what you guys thought

There are several different ways to define qualifications such as "most venomous" or "most dangerous" or "most deadly".

Lets set aside for a moment the trues vs. mygs thing and include Atrax in the list of possibles.

Ok, A. robustus will probably kill you the fastest. That's not because it has the strongest venom. It has strong venom, yes, but it is so deadly because of the huge amount it injects. Also it is only this effective against primates for some reason and much moreso with the male spiders than females. They also live in urban/suburban areas and come into fairly regular contact with humans.

The Sicarius species (I forget which one is the most deadly) has much stronger venom then A. robustus but doesn't inject nearly as much. It also won't kill you as quickly but if you get bitten you very well may die but you will almost certainly lose a significant amount of tissue, leaving you maimed or even crippled, depending on the bite location and other factors. Not as deadly but arguably more venomous (stronger venom). They very rarely come into contact with humans naturally.

Phoneutria are not as dangerously venomous as either of those two spiders. It is still very dangerously venomous though and very aggressive (defensive, whatever) It also comes into contact with humans very regularly through banana cultivation, etc. They will bite defensively and tend to not back down. It's likely that a high percentage of encounters with this species result in an envenomation when compared with other dangerous spiders. There has also been quite a hubbub here lately over these spiders' ability to become invasive. This has more to do with a whole combination of their traits than one. These same traits (speed, aggressiveness, potency, glass climbers) make them almost certainly more dangerous to keep in captivity than Atrax or Sicarius.

So yeah, it's a tricky question to answer. Most venomous? Most dangerous? Most deadly? It could be 3 different spiders depending on how you choose to define these terms.

Personally, I think of highly venomous creatures like radiation exposure; I know it can be very, very bad but I have no desire to know exactly how many rads it will take to kill me vs how many it will take to just make me sick. Same with venom, I don't wanna know. I just know it can be really bad and that is enough for me.

These posts might be useful to you:

http://arachnoboards.com/ab/showpost.php?p=1557546&postcount=16

http://arachnoboards.com/ab/showthread.php?t=127192&highlight=sicarius

Venom said:

These posts might be useful to you:

http://arachnoboards.com/ab/showpost.php?p=1557546&postcount=16

Click to expand...

That's nice, Venom (that's nice venom), but if you'd have provided some references, it would be nicer.

Zoltan said:

That's nice, Venom (that's nice venom), but if you'd have provided some references, it would be nicer.

Click to expand...

I did, for the Sicarius stuff. If you scroll down a bit in the second link, you will find this:

Venom said:

"Sicarius venom can cause disseminated intravascular coagulation with renal failure."

Cited from:

http://books.google.com/books?id=20...&hl=en&sa=X&oi=book_result&resnum=5&ct=result

"Autopsies (of test rabbits) revealed extensive subdermal tissue damage and patechial haemorrhages in the liver, lungs and heart"

Cited from:

http://www.spiderclub.co.za/medical.html

"It is striking that venoms of L. laeta and Sicarius yielded an order of magnitude more total venom protein upon electrostimulation than the other Loxosceles species surveyed (Table 1). Furthermore, SMD activity per unit total venom protein was comparable between these species and the Loxosceles species that have well-documented and serious dermonecrotic effects on human tissues. If the severity of lesion formation is positively correlated with absolute amounts of SMD, bites from L. laeta and Sicarius may be capable of inducing more severe reactions than other species. Analyses of the effects of Sicarius venoms in rabbits indicate that dermenecrotic lesions develop more rapidly after Sicarius bites than after bites of South African Loxosceles (Newlands, 1982; Newlands and Atkinson,
1990a). In fact, some African researchers have touted Sicarius as the most dangerous spider known; however, the biology of these animals makes human envenomation events rare."

Cited from:

http://www.lclark.edu/~binford/SMDDistribution copy.pdf

"Six-eyed sand spiders have a virulent cytotoxic poison capable of destroying tissue around the site of the bite and throughout the body, causing massive internal bleeding. Tissue damage from a bite can be extensive and severe, but bites to humans are not well documented. However, under experimental conditions, rabbits envenomated with Sicarius venom died within 4-6 hours and autopsies revealed extensive damage to subdermal tissue and skeletal muscle. Also, there was swelling of the liver and damage to heart and kidney tissues as well as blocked arteries in the lungs."

Cited from: http://www.afpmb.org/pubs/Field_Guide/field_guide.pdf


You might also check out:

Kurpiewski, Gretchen et al. “Platelet Aggregation and Sphingomyellnase D Activity of a Purified Toxin from the Venom of Loxosceles Reclusa.” Toxicology, vol. 96, pp. 166-167 (1982).


And for a laugh: I'm not the first to compare the effects of Sicarius envenomation with Ebola,

http://www.sciencedirect.com/scienc...serid=10&md5=1bd0fe24c3b455858fdb3007f2fb94b3

Click to expand...

As for the info in the first link, a lot of that is simply the product of years of immersion in the literature on this subject, and I can't easily or quickly resurrect all the sources that went into producing that chart. However, some links for death stats, and LD50 figures I can give. So, as requested:


LD50 of the female Phoneutria nigriventor, cited at .00063 mg/ kg in mice, with males at .00157 mg/ kg.

http://www.ncbi.nlm.nih.gov/pubmed/12368110


Ranking of Atrax/ Hadronyche funnelwebs: ( a post by Steve Nunn. If you don't know who he is...well, he's the guy who collected Steve Irwin's inverts for the Australia Zoo, and President of the Australian Tarantula Association...so, quite a knowledegable guy. )

http://www.arachnoboards.com/ab/archive/index.php/t-4018.html




A study of Loxosceles laeta ( just L. Laeta ) hospitalizations:

"A panoramic sight of epidemiological, clinical and experimental studies, referring to Loxosceles laeta and loxoscelism, carried out in 1955-1988, in Santiago, Chile is presented. Two-hundred and sixteen cases of loxoscelism were studied. The most relevant features were: 84.3% corresponded to cutaneous loxoscelism (CL) and 15.7% to viscerocutaneous loxoscelism (VCL);........The condition of patients in the last follow up was: complete cure in 75.5%, cure with a scarfed sequela in 8.3%, death in 3.7% (all VCL) and abandonment in 12.5%"

http://www.ncbi.nlm.nih.gov/pubmed/2577020




Another article which claims: "Systemic loxoscelism is much more common following South American Loxosceles species bites (L. gaucho, L. laeta, L. intermedia) with a prevalence rate of 13.1% and a case fatality rate of 1.5% in 267 cases of expert-confirmed L. laeta or L. intermedia bites."

http://www.ajtmh.org/cgi/content/full/71/2/239



A case-by-case analysis and presentation ( with extensive, GRAPHIC pictures ) of Loxosceles spp. envenomations in S. America, conducted by the University of Peru.

http://gorgas.dom.uab.edu/2008cases/080218d.html

As for the Latrodectus stats, it is well known that they have caused more deaths than the Australasian funnelwebs. This is due mainly to their world-wide distribution, but also to their likelihood of causing anaphylaxis, their wide-spread contact with man before the advent of antivenoms, and the peculiar nature of their high kDa toxin.

These and many more sources went into the rankings I gave. But I agree, sources are always good. ( just not always easy to dig up from ages past!)

I was only asking about the post in the first link, but yes, I read the second one now too. Thanks for taking to time to post sources.

Venom said:

a post by Steve Nunn. If you don't know who he is...well, he's the guy who collected Steve Irwin's inverts for the Australia Zoo, and President of the Australian Tarantula Association...so, quite a knowledegable guy.

Click to expand...

I think I've heard the name somewhere before... ;P