# Gnaphosa sp.



## jsloan (Apr 24, 2010)

*Gnaphosa sp. (Gnaphosidae)*

This adult female is so sleek and colorful I had to post a picture!   It just molted a few days ago, but I haven't been able to figure out the species yet.  Based on what the keys describe for this genus, it looks like I'm going to have to dissect out the epigyne and look at it from the inside.  If, or when, I figure it out I'll post an update.  BL = 7.5 mm


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## cacoseraph (Apr 24, 2010)

that looks like a much prettier version of my "old enemies"

gnaphosidae were my bane for many years when hunting for tiny mygs... when i was just getting started.  they constantly confused me and had me digging out the blasted spider out of its webbing only to find it was another freaking gnapho.  then when i finally started actually catching the mygs i was like.. man, these really don't look anything like gnapho webs =P


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## spider pest (Apr 24, 2010)

cacoseraph said:


> that looks like a much prettier version of my "old enemies"
> 
> gnaphosidae were my bane for many years when hunting for tiny mygs... when i was just getting started.  they constantly confused me and had me digging out the blasted spider out of its webbing only to find it was another freaking gnapho.  then when i finally started actually catching the mygs i was like.. man, these really don't look anything like gnapho webs =P


This is funny. I found something that looks similar to the spider posted above a couple days ago, although larger. When I first lifted the log it was under and saw something dark in some webbing, I had a "could it be?" moment. Still, cool spider.


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## marclar (Apr 24, 2010)

Whats also funny, yesterday on the way home from school I saw one, and bent down real fast cus' I thought it was an a affinis(didnt have glasses on) cus they the only mm's we get in ireland, but it was just one of these guys, did the exact same today.


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## PhilR (Apr 26, 2010)

marclar said:


> Whats also funny, yesterday on the way home from school I saw one, and bent down real fast cus' I thought it was an a affinis(didnt have glasses on) cus they the only mm's we get in ireland, but it was just one of these guys, did the exact same today.


You are not going to see _Atypus affinis_ wandering about


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## cacoseraph (Apr 26, 2010)

well, i mean... mature males are found in all kinds of goofy places... but i wouldn't want to bet a penny on seeing a mature female wandering around.

though, my buddy from texas *did* score a MF female trapdoor spider FROM HIS LIVING ROOM FLOOR one time!  he has also caught a ~5-6"BL Scolopendra heros from the same room.  all stuff that wandered in, 100%!  only in Texas, man... only in TX =P


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## zonbonzovi (Apr 26, 2010)

The spinnerets look strange- very blunt...maybe just an anomaly from the pic.


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## cacoseraph (Apr 27, 2010)

one of my simple field diagnostics for gnaphosidae is short, blunt, squared spinners.  those ones do like a tiny bit more angular than i would expect... but i've also never taken such a nice pic of one so that could be it =P


now i'm kind of wanting to see a video of a gnapho spinning their tube webs. hmm... maybe i could make a rig or something. catch a fem almost as big as sloan's. hmm hmm.


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## jsloan (Apr 27, 2010)

zonbonzovi said:


> The spinnerets look strange- very blunt...maybe just an anomaly from the pic.


Nope, that's the way they are.  Here's another shot from directly above:


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## jsloan (Apr 27, 2010)

Most of the readers in this forum probably already know this, but for everyone else I thought I'd mention how I determined the genus for this spider.  Spiders in the genus _Gnaphosa_ have a "serrated keel" on the retromargin (inside margin) of each chelicera.  According to Dondale and Redner*, no other genus of Gnaphosidae in north america has this feature.  Here's a picture I took showing the keel on the chelicera of a _Gnaphosa parvula_, as an example:







Speaking of the "blunt" spinnerets, if I get the chance I'll take a closeup picture and post it.  Might not be until the weekend, though.

* _The Ground Spiders of Canada and Alaska_, 1992


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## Zoltan (Apr 27, 2010)

Hey John,

I didn't know it, so thanks for posting this. Doesn't retromargin mean outside margin, though? Or more precisely, ventral or posterior margin?


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## jsloan (Apr 27, 2010)

cacoseraph said:


> one of my simple field diagnostics for gnaphosidae is short, blunt, squared spinners.


Speaking of spinnerets, I was fooled by a spider I collected last August.  Along with the squared ends, I also look for some separation between the spinnerets for gnaphosids, but that feature wasn't so apparent in this particular  spider.  That and the general appearance and size (BL = 10 mm) made me think it was a clubionid of some kind.  But, the separated cylindrical spinnerets showed up under magnification and it turned out to be _Orodrassus canadensis_ (Gnaphosidae):


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## jsloan (Apr 27, 2010)

Zoltan said:


> Doesn't retromargin mean outside margin, though? Or more precisely, ventral or posterior margin?


Retromargin = posterior margin or edge of the fang furrow, which is the "inside" margin next to the maxillae.

Promargin = anterior margin or edge of the fang furrow; the "outside" or front side.

It's not easy to see, but the side of the chelicera in the picture above is the inside, normally tucked up against the maxillae and labium.


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## Zoltan (Apr 27, 2010)

jsloan said:


> Retromargin = posterior margin or edge of the fang furrow, which is the "inside" margin next to the maxillae.
> 
> Promargin = anterior margin or edge of the fang furrow; the "outside" or front side.


I'm starting to get it now. I guess it's because I'm used to mygalomorph chelicerae, where the promargins are the parts on the inside of the chelicerae. Here's a crappy illustration of what I mean, ventral view:


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## cacoseraph (Apr 27, 2010)

jsloan said:


> Speaking of spinnerets, I was fooled by a spider I collected last August.  Along with the squared ends, I also look for some separation between the spinnerets for gnaphosids, but that feature wasn't so apparent in this particular  spider.  That and the general appearance and size (BL = 10 mm) made me think it was a clubionid of some kind.  But, the separated cylindrical spinnerets showed up under magnification and it turned out to be _Orodrassus canadensis_ (Gnaphosidea):


lanky legs for a gnapho, too.  would not have been my first guess, at all


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## jsloan (Apr 27, 2010)

Zoltan said:


> I'm starting to get it now. I guess it's because I'm used to mygalomorph chelicerae, where the promargins are the parts on the inside of the chelicerae. Here's a crappy illustration of what I mean, ventral view:


Okay, now I see where you were coming from.  That makes sense, because if you rotate the mygalomorph chelicerae in your drawing so that the fangs end up pointing toward each other, as in true spiders, the promargin would then be along the front of the spider and the retromargin would end up on the inside next to the maxillae.


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## jsloan (May 1, 2010)

A closeup of the spinnerets (ventral view):


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