is also in California, according to the 1975 Bowling and Sauer revision on our info. page for Bassaniana (fig. 22). It's still not totally clear to me why this couldn't be that species, but I'm leaving this up to you two and Lynette for now...

I don't doubt the ID, but can you please tell me how you decided on this genus?

and I'm right in the middle of it... but I will do my best. Based on eye arrangement and flat carapace it's not Xysticus (John Balaban just taught me this today) and then I did some further research (see the genus info pages) and found that Coriarachne has no white markings on the carapace... so by process of elimination it must be Bassaniana. I also think that based on the ranges I found on the PDF article it has to be B. utahensis.

Thanks for explaining your logic! I will see if I can find a mature member of the species to try to match up a palp or epigynum as well.

and after a little more research I'm not sure this isn't Ozyptila. John B. got info from John Sloan to look for Tibia with two spines and swollen femurs. I guess you should look here as well? There seems to be a bunch of them. And I should clarify that Coriarachne has no white band on the carapace... not necessarily the same as no white at all.

Here's my understanding of how to separate these genera:

* The number of macrosetae on tibia I, and the width-to-length ratio of femur I, are used to separate Ozyptila from Xysticus, but not necessarily from Coriarachne or Bassaniana.

* Ozyptila and Xysticus are both distinguished from either Coriarachne or Bassaniana by the lateral profile of the carapace: as Lynette mentioned, in both Coriarachne and Bassaniana the carapace is roughly flat all the way from front to back. The side profile of the carapace for Ozyptila and Xysticus, on the other hand, will be higher near the front and will drop down near the back at around coxa three. Coriarachne and Bassaniana maintain roughly the same level height from front to back.

So, the order of things to check when separating Xysticus, Ozyptila, Coriarachne and Bassaniana is:

1) Check carapace flatness first, to separate Coriarachne and Bassaniana from Ozyptila or Xysticus

2) Then, check the ventral macrosetae on tibia I and femur I length/width ratio to separate Xysticus from Ozyptila.

Ozyptila: - no more than 2 pairs of ventral macrosetae on tibia I .... femur I length-to-width ratio is about 3:1

Xysticus: - 3 to 4 pairs of ventral macrosetae on tibia I .... femur I length-to-width ratio is about 4:1

As for separating Coriarachne from Bassaniana, Lynette knows more about that than I do. :)

Anyway, that's how I've been separating these genera, using the information from Spiders of North America, Ubick et al. (2005) page 247.

Looking at Ken's spider, I think we need a picture showing a clear side profile of the carapace to help us decide which genus it belongs in.

I think this spider has a very flat carapace, so probably not Ozyptila.

I was separating crab spiders in my dreams last night!

So maybe an immature Coriarachne? I guess there might just be some pigmented areas near the book lungs, although some of the structures do look like they might be part of an epigyne.

Yes, I'd say either Coriarachne or Bassaniana, depending on the species (I think there was some recent rearranging of those genera).

I was thinking those pigmented areas in the epigyne could correspond to atria, but are they "excavated?" Can you see definite openings or depressions there when you look at the specimen? I'm looking at drawings of mature epigynes in Paquin & Duperre (2003) and they all look like the atria are open, and there is a distinct septum down the midline that divides them.

they appear flat under the scope and I don't see any definite openings. It looks more like roughened pigmented areas surrounding rectangular depigmented areas. I was more struck by the quite lateral elongated structures that look a bit like spermatheca or ducts (?)