Some Alberta Crab Spiders

jsloan

Arachnoangel
Old Timer
Joined
Jun 22, 2004
Messages
972
Thought I'd post images of the various species of Xysticus males I found last year, and also so far this season. Quite a variety from just around my place! Most were collected by pitfall traps. By far, the most abundant at the moment is X. emertoni (and it's also the largest). Maybe I'll add images to this thread as I find more species (including females) throughout the summer. A few look too much alike for me to tell them apart by general appearance, so I identified each one by its palp. My goal is to get photos of every Alberta species (I might have to do some travelling for that - don't know if they're all found in this one area).

Xysticus emertoni:


Xysticus ferox:


Xysticus britcheri:


Xysticus obscurus:


Xysticus ellipticus:


Xysticus luctuosus
 

John Apple

Just a guy
Old Timer
Joined
Jan 26, 2003
Messages
1,148
Very cool indeed, you must have put in some time searching for all males only for the photo session:)
 

zonbonzovi

Creeping beneath you
Old Timer
Joined
Oct 20, 2008
Messages
3,346
Nice, pics, sir! Any advice on location placement of pitfall traps for crab spiders?
 

jsloan

Arachnoangel
Old Timer
Joined
Jun 22, 2004
Messages
972
Very cool indeed, you must have put in some time searching for all males only for the photo session:)
No, I just found mostly males is all. These photos are from several different photo sessions. Usually, I photograph unusual specimens soon after returning with them from the traps, then I put them in vials with dated labels and numbers. Later, when I get around to identifying them, I can link each one to its correct picture.
 
Last edited:

jsloan

Arachnoangel
Old Timer
Joined
Jun 22, 2004
Messages
972
Here are a few females to go with the males:

Xysticus obscurus:



Xysticus ferox:



Xysticus ellipticus:



Color is not always a good feature to use in identifying these spiders to species, because it is variable. I've recently found some X. ferox that are a little darker/browner than the one shown above.

Here are two version of a female Xysticus emertoni:

Light version:


Darker version:
 
Last edited:

TheTyro

Arachnobaron
Old Timer
Joined
Aug 16, 2009
Messages
418
Crab spiders are some of the few spiders I rarely take the time to try and identify...they all look so similar at a glance..heck, they all look similar up close...a formidable task but it's great you are taking it on. A project like that would take me years, mostly because I can't kill spiders ahead of their time...I'd have to wait for them to die naturally before I tried getting a look at their spidery bits.

The only type I try identifying are ones that look terrifically different than the sort I usually see...but that isn't often, and that also seems difficult because there tend to be a lot of em that look similar to one another, even though they look..unique...if that makes any sense.

I'd love to see a Xysticus ellipticus in person though, it's abdomen looks like a pebble! Thats awesome.
 

Toirtis

Arachnobaron
Joined
May 14, 2010
Messages
316
Give me a shout when you are in Calgary...I would love to help search for what you do not have down here.
 

jsloan

Arachnoangel
Old Timer
Joined
Jun 22, 2004
Messages
972
Give me a shout when you are in Calgary...I would love to help search for what you do not have down here.
Will do. I might be passing through there later this summer, if I can make the trip, heading to the Lethbridge area to collect some Latrodectus herperus.
 

jsloan

Arachnoangel
Old Timer
Joined
Jun 22, 2004
Messages
972
The only type I try identifying are ones that look terrifically different than the sort I usually see...but that isn't often, and that also seems difficult because there tend to be a lot of em that look similar to one another, even though they look..unique...if that makes any sense.
It makes a lot of sense. Even specimens of the same species can look different from each other. I can barely distinguish between the look-alikes without checking the palp or epigyne. Fortunately, the palps are unique and its easy to separate the species with them; the epigynes are a little tougher, but not too bad with a little practice.
 

Toirtis

Arachnobaron
Joined
May 14, 2010
Messages
316
Will do. I might be passing through there later this summer, if I can make the trip, heading to the Lethbridge area to collect some Latrodectus herperus.
Leth is good, Medicine Hat seems better...Paruroctonus boreas plentiful there, too.
 

sygdom

Arachnosquire
Old Timer
Joined
Feb 16, 2009
Messages
56
Wow those are some really cool pictures. Just shows you how diverse these things really are. I tried setting up some pitfall traps over the weekend and unfortunately had no luck, at least in the spider department :). I am going to attempt to relocate them this weekend and hopefully have a little better luck. I was going to put them under some of my trees and bushes.
 

jsloan

Arachnoangel
Old Timer
Joined
Jun 22, 2004
Messages
972
I've been lookin for a female of this species for a long time. Finally found one about a week ago on a poplar sapling.

Xysticus punctatus:



Side view:

 

jsloan

Arachnoangel
Old Timer
Joined
Jun 22, 2004
Messages
972
Normally these spiders are difficult to identify from pictures, because they look very similar to one another; but, I can see part of the palp in your spider called the "tegular apophysis," which is fairly large and sticks out to the side just a bit. I'd have to examine it close up to confirm the species, but your spider might be Xysticus emertoni.

Here's a picture of a Xysticus emertoni palp to give you a better idea of what I mean. The tegular apophysis is the long thick, black pointed structure that looks kind of like a knife blade and is pointing to the left. In most other species of Xysticus that structure isn't as large, but there are some species other than X. emertoni in your area that come close and it might be one of them as well. So, Xysticus emertoni is just a best guess for an ID, but that's what I'd go with for now. :)

This Xysticus emertoni palp is from a specimen I collected in Alberta:

 
Top