Linothele sp. True spider or Tarantula?!?
 

I got a Linothele magdalene today. They are "magalomorphs" as tarantulas but from what I've heard they are considered to be true spiders?

Does anyone know anything about this? Any information about Linothele is appreciated,

Thanks!

From what I've read, Linothele is a genus in the family Dipluridae. They are true spiders. Can't find too much other info on that genus though. Is it a fishing spider by chance?

Atrax

I always thought that a key devider between true spiders and tarantula's was fang position [magalomorph vs arenamorph] yet here is a true spider with tarantula fangs what else devides spiders from tarantula's

No it's not a fishing spider. They pretty much act like T's and make alot of webbing.

Take a look at one at this url:

http://gutt.sg.free.fr/Images/jp29.jpg

Ok, I am pretty limited in this type of thing so I hope I get this straight.
A Mygalomorph is a true spider with parrallel fangs. Many Mygales are kind of somewhere in between T's and trues. Trapdoor spiders are a good example. Also Funnelweb Spiders, Mouse Spiders etc.etc..

Hope I got that right...and hope it helps too..

Atrax

Ah, thanks for the reference. Pretty cool looking Mygale! Reminds me of a Barychelid a little bit.

See ya.

Atrax

From the mygale family Dipluridae. All mygales (Mygalomorphae) possess the par-axial fangs, unlike "true" spiders (Araneomorphae) , which is just such a crap term it isn't funny. Mygales are just as much "true" spiders as araneomorphs. I prefer "primitive" to describe mygales and "modern" to describe araneomorphs.

Here's a couple of basic differences to help: Araneomorphs possess a cribellum, which is a comb like appendage situated near the anus. The cribellum is what allows araneomorphs to spin several different types of silk. No mygales possess a cribellum.

As mentioned above all mygales have par-axial fangs, while araneomorphs have pincer like fangs. Mygales have two pairs of booklungs while araneomorphs have only one.

Mygales went their own path just before the Permian Period (286 million years ago), while the araneomorphs began their existance, along with the Hypochilomorphae (some call them the "living links", two pairs of booklungs, yet they possess pincer like fangs.)

If anything, theraphosids are actually less of an ancient spider then the diplurids.

Steve

There are some that believe the downward pointing fang is not so much a 'primitive' development, but just one of two paths possibly taken from the truly primitive spiders (the segmented abdomen liphis...yeah.. They have somewhat of a compromise in the fang structure, where they point almost 'diagonally', and not pincher-like or straight down. Steve, what the hell do you call those things, I can't remember.. Plaigiognaths?

Bill

Hi Bill,
From the sub order Liphistiomorphae, one family, Liphistiidae, two genera, Liphistius and Heptathela.

Good point regarding the fangs, the mygale genus Actinopodidae also possess diagional facing fangs, possibly leading to a belief that the primitives fang structure, even though it is an apomorphic character, is closer to the original state.

Cheers,
Steve

I believe Foelix mentions something of this in the book iirc. It is such a set of crap terms when it is very likely that both sets are equally diverged from the proto-spiders and adapted for two completely different lifestyles (ambush hunting versus trapping).

Personally, I prefer the old terms orthognath and labidognath since they are more descriptive and accurate than mygalomorph and araneomorph. The first two are literally straight-jaw and grasp(ing)-jaw, which is the most obvious difference between the two groups. Araneomorph means literally "spider form" or "spider shape" as if Ts and their relatives don't look like spiders. Mygalomorph is worse since literally it means "field mouse/shrew shape/form". Most of us know that the term mygale was borrowed to refer to Ts in the early 19th Century, so we can interpret it as "mygale spider form/shape" but that's hardly descriptive since you already have to know what that type of spider looks like to understand what it means, whereas the two 'gnaths', when translated for someone who had no knowledge of cheliceral orientation in spiders, would actually provide new information.


As far as primitive and modern, I prefer not to use primitive because it carries a negative connotation. The 'modern' spiders have evolved all kinds of sophisticated, advanced behaviors, but the 'primitives' have managed to survive all this time with very little change. I think there's something to be said for making it through multiple catastrophic extinction events and several smaller ones with much the same set of tools you started with.

Adrian