Non-venomous.... Which Families?

thevez2

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Which spider families are non-venomous?

Uloboridae is one. I think there is one more, but I can't find it.

Thanks
 

basin79

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Which spider families are non-venomous?

Uloboridae is one. I think there is one more, but I can't find it.

Thanks
I know they're not true spiders but I think Liphistius aren't venomous.
 

chanda

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USMuscle9403

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Liphistius were believed to lack venom, but they were discovered to have small venom glands and venom gland openings in their chelicerae. I have read that the closely related Heptathela lack venom glands completely - or at least nobody had been able to find them yet.


https://www.researchgate.net/publication/259855147_Mesothelae_have_venom_glands
My understanding was that they (Liphistius) had venom glands, but they weren't connected to the fangs. Interesting info, thanks.
 

The Snark

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The non venomous subject came up some time ago in my correspondence with Rod Crawford. In essence, it is purely academic at this stage of the game.

-There are approximately 45,000 tentatively identified species of spiders. Since different methods have been used in the classification this is only a rough guess.
-There are approximately 32,000 properly identified spiders using specific anatomy in the identification.
-There are approximately 2500 genetically described species - the definitive entirely accurate identification. The results of the genetic classification sometimes disputes the other standard methods of describing.
-By statistical analysis there should be approximately 95,000 species of spiders +/- 15%

Entering into this is certain species which go under the general classification of non venomous. This in turn is broken down into, has no venom glands, has no venom delivery system, has both no venom glands or delivery system, has lost glands and/or delivery system, and is developing glands and/or delivery system.

So the definitive answer to the OP's question is slightly more difficult to answer than why chickens cross roads. Give the brainiacs a century or two and a more accurate figure will probably be forthcoming.
 

The Snark

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Addendum. The venoms of spiders directly correspond to their historical time lines. Venoms vary drastically and are indicators of the prey the particular species commonly encountered during it's evolution.
An excellent example of this is the venoms of Latrodectus. Seven different extremely complex proteins, one of which specifically targets crustaceans. When, where and how latros developed a taste for, say, antedeluvian oysters is one of those sweet mysteries of evolution on this planet that we may never fully fathom.


I take my mind and imagination off the leash for the moment and regard the larger picture. From the hostile arid deserts of the Autralian outback to the swamps of Florida, all Latros possess that same crustacean targeting venom. Now all we need to do is build a super computer which I suspect would be the size of Kansas that could ferret out the common denominator and give us the several million year ago window as to the origin of that genus.
 

schmiggle

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Addendum. The venoms of spiders directly correspond to their historical time lines. Venoms vary drastically and are indicators of the prey the particular species commonly encountered during it's evolution.
An excellent example of this is the venoms of Latrodectus. Seven different extremely complex proteins, one of which specifically targets crustaceans. When, where and how latros developed a taste for, say, antedeluvian oysters is one of those sweet mysteries of evolution on this planet that we may never fully fathom.


I take my mind and imagination off the leash for the moment and regard the larger picture. From the hostile arid deserts of the Autralian outback to the swamps of Florida, all Latros possess that same crustacean targeting venom. Now all we need to do is build a super computer which I suspect would be the size of Kansas that could ferret out the common denominator and give us the several million year ago window as to the origin of that genus.
The Latrodectus protein targeting crustaceans actually makes good sense--it probably targets isopod prey. The only place with Latrodectus that I know of that might not include isopods is the Australian outback, and it is likely that latrodectus did not evolve there. The vertebrate-specific one is more surprising to me, although it might just be a defense mechanism.
 

The Snark

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The Latrodectus protein targeting crustaceans actually makes good sense--it probably targets isopod prey. The only place with Latrodectus that I know of that might not include isopods is the Australian outback, and it is likely that latrodectus did not evolve there. The vertebrate-specific one is more surprising to me, although it might just be a defense mechanism.
Nod nod. So many unknowns and mom nature, the progenitor of infinite variables. One interesting wrench in the works is the area in the Kakadu region of the Australian Northern Territory where L Hasseltti have been fully established for an unknown period of time. That region has never been under water. There is no evidence that during ice ages and continental shifts that it was significantly different in topography, geologically, botanically and biologically for several million years. So we have a living window into the distant past, and a spider with very unusual venom traits that evolved, or didn't evolve, over that time period until now. Since Hasseltti has the same venoms as that of Latrodectus species found in other areas, how the Latro came about, when and where is a mind bending conundrum. Was Hasseltti the origin progenitor of the genus? And if so, can we somehow build bridges into the present and using those as models to take it back into the very distant past?

As a footnote. A stroll through the Kakadu is mind bending. Pardon my being unscientific but you can feel the age. It is old, unchanging. Well worth a visit if you have the wherewithal.
 

Nephila Edulis

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if spider venom evolves specifically for the main prey item then why is the male atrax robustus so deadly to primates (which it did not evolve with) and not to other animals?
 

The Snark

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if spider venom evolves specifically for the main prey item then why is the male atrax robustus so deadly to primates (which it did not evolve with) and not to other animals?
Good question. Could be accidental, incidental, or entirely arbitrary. Mom nature does occasionally use 12 gauge magnum buckshot to hunt ants.
 

The Snark

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if spider venom evolves specifically for the main prey item then why is the male atrax robustus so deadly to primates
The same could be said for the inland Taipan. This could even be a vote for intelligent design... if Cheech and Chong built the palace:

Cheech: "Hey man! Check out these bad boys. They could even take down the big ones.
Chong: "Uhhhh, dude. I put all those over in Africa."
Cheech: "So what I got over here?"
Chong: "Uhh, mostly marsupials."
Cheech: "MarWhats?"
Chong: "Yeah man. Check it out. I got one that's sort of like a duck but it's got four legs and fur. And a pouch. And little nasty spurs on it's heels!"
Cheech: "Maaan! How much did you smoke last night?"
 
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