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Crab Spider  - Xysticus possiblefunestus

Crab Spider - Xysticus possiblefunestus
San Antonio, Bexar County, Texas, USA
February 26, 2010
Found this spider in my kitchen while I was sweeping the floor, I think it was hiding near the baseboards. I put it on a piece of paper and took it outside.

Is it a Ground crab spider (Xysticus)?

Thanks for any help! It's appreciated.

Images of this individual: tag all
Crab Spider  - Xysticus possiblefunestus Crab Spider  - Xysticus possiblefunestus Crab Spider  - Xysticus possiblefunestus Crab Spider  - Xysticus possiblefunestus Crab Spider  - Xysticus possiblefunestus

Moved from ID Request.

I'm a little torn between Xysticus and Ozyptila...
I can't see the spines on the first tibia, and can't tell if the hairs on the carapace are club-shaped or not. More than two spines on the first tibia means Xysticus, while only two means Ozyptila. And if the carapace hairs are club-shaped, that points to Ozyptila as well. Do you happen to have any more images that might show these things? I'm not sure why the first tibia leg spines didn't show up in this image... it seems that the short ones on the second metatarsus showed up fine. Weird. It's a neat looking female!

Added two more pictures...
I hope they help!

Thanks Mandy. :)

edit: after trying to figure out what the tibia was (3rd leg segment up from the ground?) I can see lots of hairs on the leg...are those the "spines"? I'm still learning spider anatomy. :) If so, then my girl is a Xysticus. Can you see them better in the two new photos? *crossing my fingers*

Awesome! Thank ya, ma'am. :)
Thanks for adding the additional photos! I could see the tibial spines very well in those. And you interpreted everything right; she's a Xysticus alright! So you were correct (in your original post remarks). My first thought was also Xysticus, and I even knew where this gal should be placed, but I wanted to confirm some things first and make sure it wasn't a look-alike of something else. If you check that link, you'll see that we haven't figured out this groups' species yet. One of us needs to see the genitalia of one of these to be able to determine a species; so far no submissions show them/it. If there's an off chance that you took some photos of the underside of this chica, that would be d-y-n-o-mite!!

Yep, that's were the tibia is, and those are indeed the spines. Technically, they'd be called macrosetae. The regular, non spine-type hairs are just plain setae. Spiders always have seven leg segments and six pedipalp segments (after all, the pedipalps are just modified legs). From the carapace to the tips of the claws, in order:
coxa (small segment that attaches to the main body, next to the sternum)
trochanter (another small segment, but very important; similar to an elbow, in that it creates the angle that the whole leg will maintain based on the genetics of the species; your crab spider has laterigrade leg orientation which means this segment has been rotated in such a way that the legs will lay flat; usually the 'norm' is prograde leg orientation, which is when the front legs point forward and the back ones face backward all whilst maintaining an upward angle)
femur (usually the longest, buffest looking segment, similar to our human femurs)
patella (basically the knee; a small segment)
tibia (another longer segment; not good for much except creating length, lol)
metatarsus (next-to-last; medium sized; sometimes referred to as the basitarsus)
tarsus (semi-short and last segment; includes the tarsal claws)
Found this diagram on the araneae info page. You may have seen it already, but it'll help if you are a visual learner:

Just keep in mind this diagram is of a female spider. That epigyne area is exactly what we need to see in order to ID all the specimens that look like yours. (as well as LOTS of other spiders in the guide!) Oh, and nobody really calls spider chelicerae "mandibles", at least nobody that I know of. So ignore that labeling, lol.

For the pedipalps (usually just called "palps" for short) all the segments are named the same way in the same order, except the metatarsus is "missing". So you'd go straight from the tibia to the tarsus. In male spiders, as you probably know, the palps are enlarged. Those enlarged portions are the tarsal segments, and since it's a male it's now called the palpal bulb or male genital organ, but usually just "palp" for short. The palpal coxa and trochanter are harder to see than their equivalent leg segments. A lot of people don't know this, but the coxal segment is attached sort of behind the chelicerae and fangs and is usually called either the endite or the maxilla in published literature. This segment is often evolved to be an aid in chewing food... sometimes growing really big and looking like the end of a spatula. The chelicerae rub and mash against it like a medieval maid doing laundry on a scrub board. Then the spider can slurp up its supper with ease. If you're interested, you can see the endites (probably the most commonly used term for them) in this example; they are just what I was talking about-- evolved to be a chewing aid:

The endites are the two spatula-type things behind the chelicerae and fangs. As an example, I chose a species that showed them well but you have to look a bit harder and/or closer in lots of other species.

I'm really sorry if this is all old news for you, or if it's simply boring and annoying or unnecessary. I am pretty passionate about spiders (can you tell?) and if someone says something like, "I'm still learning..." or "I don't know what..." I can't help but gush with knowledge that I've acquired, in the hopes that others will learn it and pass it along when it's their turn, you know? And part of me really wants to recruit other humanoids to the arachnophilic army. There is strength in numbers, no? And there's not many arachnologists/para-arachnolgists in this world.

But, if nothing else, if someone does a search for any of these terms they may come across this and find it a tad bit useful. Who knows. I am frequently finding myself in this exact position. Always trying to find excuses for my spider ramblings, LOL. But please don't let this novel of a reply hinder you from ever asking me (or anyone else) any questions you may ever have about spiders (or any other creatures). With some more time on the site, you will become accustomed to who knows what about what type of creature and can then aim your questions in the proper direction 'n such.

Welcome to Bug Guide, by the way! I remember your first forum post about a month ago. This is such a great site, you won't regret joining. I love it! ...And have met some very spectacular people because of it.

This may be a record length reply for me! Guess I was in the right mood, eh?

Thanks for all the info...
it's very useful to me. I'm the type of person who wants to know everything there is about a subject once I'm hooked in but I have so much on my plate and no formal training yet so any info you can share is very much appreciated.

I wish I had a picture of her underside but she was kind of freaking me out, I can't say I'm scared of spiders but getting so close and personal with them on the macro end is a little creepy for me still - I'm hoping I'll get over that the more I take macros of them. :) I put her outside so I'll probably never find her again but if I see another one I'll try to get a photo of the epigynum (used your diagram that you linked to so now I know what to look for when taking the photo)!!! :)

Thanks again!

Glad it was helpful
I'm also like you: I like to know everything there is to know about a subject. That's why I tend to focus on one thing or group at a time (spiders right now). I don't have any formal training either, besides college sciences (Bio, Geo, Psych, Soc, Chem, etc...) If I enjoy something, I find it easy and fun to teach myself. I remember more that way, too. I bet you're learning about all sorts of groups of creatures and such... so I feel bad for plopping a bunch of spider stuff in your lap (now that I slept on it and re-read how much I actually wrote, LOL!). Ah, well... it's all good. At least you know where the epigynum is now! :)

More than helpful.. answered all my questions plus the questions I would ask before I asked them and some I never thought about asking, which is awesome.

That crab spider had me unnerved and curious all at the same time. When I discovered it was either as scared as I was (or smarter than I was to stay still and quiet in the presence of the unknown) I took my photos and got the heck out of there!

I actually said to it, "What are you?"

And now I know. Yay!

I love "bugs" but ESPECIALLY spiders.

BTW, Mandy, please feel free to plop a bunch of spider info on me!!! :) I can take it, heh. You rock.

Ok, I'm happy then :)
I often wish that there was more info or explanation in other comments as well, so that I could learn from them (especially for the bugs I don't know much about-- which is pretty much anything with 6 legs!) So that's why I try to add extra info in my own comments, in case someone is listening! :) It depends on who you talk with, but everyone has their own opinion about the goals and directions of Bug Guide. Some people don't think it should be an "encylopedia"... only an online field guide that matches species names with images. I'm not even fully sure of my own opinion yet. But I love sharing and exchanging knowledge and will do so at any chance I get.

Even as a longtime spider lover, I will admit that there are a few spiders that do still unnerve me as well! But, shhh! Don't tell anyone. LOL!

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