Spider of some sort - Antrodiaetus

Antrodiaetus unicolor and A.

Antrodiaetus unicolor and A. robustus are both in PA... my paper only illustrated the localities of the specimens I used. It is impossible to identify the two species based on a photo. Antrodiaetus unicolor is probably the most variable species in the genus - it can be yellow to red to solid black. Antrodiaetus robustus looks much like A. unicolor, especially the females. You would have to look closely at a group of hairs on the anterior part of the abdomen to tell them apart. That being said, this is probably A. robustus based on its location in Westmoreland County.

… Brent E Hendrixson, 8 April, 2009 - 6:30pm

RE:

Thanks a ton for the clarification, Mr. Hendrixson. I've been studying Antrodiaetus quite extensively here at Berry College, and I must say your papers on this genus have been a HUGE help for me. Again, thanks for your assistance with this ID.

… Brett Tyler, 8 April, 2009 - 8:27pm

Antrodiaetus (robustus?)

This is a female Folding-door Spider of the genus Antrodiaetus. Your specimen looks somewhat different from the A. unicolor and A. microunicolor that I've seen here in Georgia. Perhaps yours is A. robustus? According to this [1] range map found in Hendrixson and Bond's paper on the Antrodiaetidae, A. robustus is the only species currently known from Pennsylvania. Also, here's a link to the Antrodiaetus page here at BugGuide: http://bugguide.net/node/view/23441

… Brett Tyler, 6 April, 2009 - 3:58pm

thank you

Thank you, but I have not been able to find any other pictures of anything anywhere (goodle included) that even looks remotely like this one, is it possible that this is a rare spider?

… Chad, 7 April, 2009 - 2:55pm

RE:

Folding-door Spiders are not really "rare" per se, they are just rarely seen unless you intentionally go out looking for them. You see, these spiders are burrowers and thus spend almost their entire lives hidden underground. Even when they do journey beyond their burrows, it is almost always at night. As a result, they have not been photographed very much at all. Your specimen looks pretty much identical to the one in this photo, which was also taken in Pennsylvania:

And again, I believe the exact species for both your image and the one shown above are of Antrodiaetus robustus.

… Brett Tyler, 8 April, 2009 - 5:12pm