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Perplexing spider - Arachosia cubana

Perplexing spider - Arachosia cubana
Onion Saddle, Chiricahua Mountains, elev. 7,600 ft., Cochise County, Arizona, USA
July 11, 2010
Size: ~<12 mm body
This little one was climbing around on the blacklight sheet. Have no clue even what family to start with.

Moved from Slender Crab Spiders.

Awesome. I couldn't verify this with any of my resources, so I'm trusting that it is right. Great new spider for the guide!

Yes, he nailed it; only species that is found in North America; others are all further south.

Platnick, 1974, is online; Hank Guarisco also published a report of specimens found in Kansas and included a small photograph (online, but $).

@Eric: Don't you wish you'd taken more photos of this "rare but widespread" species? :-)

Moved from Spiders.

Comments -
from David Richman at New Mexico State:

"This looks exactly like a Tibellus except for one detail- the eye arrangement does not seem to match! This may be an artifact of the angle, but it does make it difficult to make a positive ID. I still think that it is a Tibellus, but if the posterior lateral eyes are actually behind and further away from the posterior medial eyes, than it is for sure this genus. Two species are known from Arizona - Tibellus chamberlini Gertsch and Tibellus rothi Schick, but Tibellus oblongus (Walckenaer) may also occur there".

Suggest moving to genus page, but I'll leave it up to Eric or someone else...

Arachosia cubana (Anyphaenida
Arachosia cubana (Anyphaenidae)

Looks good! Many thanks,
Looks good!

Many thanks, Volado, for setting us straight.


(Kudos as well to Ken, for his excellent observations! Oops, John and Jane were the first to point this out.)

I think it's merely a matter of resolution (or bad luck with this image). As we know from looking at camera macro images of the epigynum, etc., when working at the edge or beyond of the functional resolution, one begins to see (or not see) all kinds of things.

So, Eric -- you are finding species in interesting locations and altitudes, but not collecting them for determination? (nag, nag) :-)


I emailed -
an arachnologist based in the Southwest with this image (don't yet have permission to quote them), who also feels that this is likely Tibellus, although the apparent eye arrangement is "off", as mentioned below.

Tibellus, IMO
Certainly looks to me like Tibellus. You might take a look at this list:


does seem right... assuming that the two posterior lateral eyes are hidden in the image above.

Moved from ID Request.

The eyes just don't work for us.
We tried Pisaurina and Thanatus, but not those eyes? We'll be following this one too.

Yeah -
I must admit that, of the ones I can see well, our Tibellus have the PLE's behind the PME's, while this one is the opposite I think. Get it under a scope! :) Maybe one of the other spider enthusiasts will recognize it.

Let me see if I can find someone who knows the spiders in the area... Do you have any other angles, esp. showing the eyes?

Well -
we have some spiders with similar patterns in Tibellus and Larinia. The leg and eye arrangement seems a little better for Tibellus to me... I'm not familiar with your AZ spiders, though, and there are probably other possibilities. Maybe someone else can be more definitive.

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