Crab Spider

Moved

… Jim Moore, 18 September, 2010 - 12:25pm

Philodromidae

Not a crab spider (Thomisidae), but rather a philodromid (Philodromidae -- the running crab spiders). Did you collect it?

… Kevin Pfeiffer, 18 September, 2010 - 10:10am

Thanks Kevin for the ID correction!

Yes I did collect it. It is pinned, with one leg now missing.

… Jim Moore, 18 September, 2010 - 12:54pm

But the spiders are soft-bodied and generally need to be stored in alcohol (e.g., 70% ethanol). Is it mature? Can you get a close-up of the epigynum from the ventral side (preferably photographed under a liquid to avoid spurious reflections)?

… Kevin Pfeiffer, 18 September, 2010 - 3:08pm

Thank you Kevin for your comment;

The specimen was pinned this last June and is now quite dried and shriveled. In my 30+ years of collecting, mostly insects, I never collected and pinned spiders until just this year. The reason I am now collecting and pinning them rather than storing them in alcohol is because I am donating them, along with most of the rest of my recent insect collection and digital images of specimens, to the University of Guelph Biodiversity Institute in Ontario (BIO). In exchange the folks at BIO will extract a DNA sequence from a leg and provide ID info - which is placed at the online database site - BOLD (Barcode of Life Data Systems). The only specimens they ask to be stored in alcohol are minute tiny specimens.

However, from now on I will try to get a good photograph of the ventral side of spider specimens for those I post at Bug Guide. Thanks for making me aware of the importance of the epigynum in spider ID'ing.

When it comes to spiders I am not real sure how to tell a mature spider from an immature one - especially those which I do not see often.

This particular 'running crab spider' seems to be close to mature size based on those similar specimens that I have seen.

… Jim Moore, 21 September, 2010 - 1:58pm

Hi Jim,

Interesting. Yes, I heard just this past weekend, at the German arachnological society conference, that drying also (that and very deep freezing) is supposed to be an effective approach for preserving material for DNA analysis. (Apparently moisture is the problem?)

With the mature females, you'll generally see a visible epigyne, with clearly sclerotized elements. But to be of any use, one generally needs an extremely good macro image (and under water) or else a photo with a microscope.

But it sounds like you will eventually be able to provide classification details without the genital inspection. So, keep us informed.

… Kevin Pfeiffer, 21 September, 2010 - 2:40pm