Currently viewing the category: "Running Crab Spiders"

Subject: I can’t find this guy in any books!
Location: Wichita, KS
October 17, 2012 6:34 pm
Dear Bugman,
Originally I thought this was a crab spider but it doesn’t match any of the pictures I’ve seen. Also, it lays incredibly flat when resting and appears to have feathery, white hairs on it’s back legs. I’m stumped! Thanks for your help!
Signature: Matt

Running Crab Spider or Flattie???

Hi Matt,
Looking at your photos and reading your description, we believe this is a Flattie in the genus Selenops.  See this photo on BugGuide which reports the genus from Texas, Arizona and Florida and notes:  “This genus is found throughout the tropics and subtropics worldwide and can be found in southern parts of the U.S.”
  Since Wichita is in southern Kansas, this is a possibility.  We cannot see any examples on BugGuide with the hairy legs, but this Australian relative on the Brisbane Insect website looks very similar to your spider.  We wish we could make out the eye pattern on your spider.  We would love to substantiate our identification with others.

Running Crab Spider or Flattie???

Correction Courtesy of Eric Eaton:  Running Crab Spider
I believe this is actually a specimen of a Philodromus sp. (“running crab spider,” family Philodromidae).  I think flatties are restricted to the southern U.S. and the tropics.

I appreciate all of the information! I’m not an expert but after reviewing both pictures, I think it resembles a Flattie more. The biggest difference appears to be size and the coloration on the abdomen. Also, the feathery appendages are different than what I’ve seen online as well. I need to get a better series if pictures and perhaps use a macro lens to photograph the eyes.
Certified Coloring Book Professional

Thanks for the update Matt.  We would tend to trust Eric Eaton’s opinion, but the photos you submitted are lacking in detail.  A good photograph of the eye arrangement would be helpful.  After Daniel’s book came out, he had a wild idea to do a children’s coloring book.  What do you think?


anatus formicinus eating unidentified caterpillar
Location: Toledo, OH
March 21, 2012 11:13 am
Afternoon, Bugman.
Ran in to this guy while chasing snakes (to photograph, not to harm) and didn’t have the heart to lift the wood he was on to follow my snake friend. Pretty sure it is anatus formicinus, but after half an hour of digging around I can not identify my caterpillar. Ah well, it was still a wonderful sight!
Signature: Katy

Running Crab Spider eats Caterpillar

Hi Katy,
We believe you have correctly identified this Running Crab Spider, though we are correcting the spelling of the genus name which is
Thanatus.  There are some photos of Thanatus formicinus on BugGuide that look very similar.  We believe the caterpillar is most likely a Cutworm or Noctuid Caterpillar, or possibly a relative of the Tent Caterpillars, but we haven’t the time this morning to do that research.  This is a thrilling spring Food Chain image.

Green spider captured
Wed, Jul 8, 2009 at 2:16 PM
I captured this spider at my wife’s request, it was sitting inside the carport.
Haven’t seen a green one before but have seen brown ones.
Kearns, utah

Nursery Web Spider???

probably Running Crab Spider

Hi Steve,
We believe this is a Nursery Web Spider in the family Pisauridae, which includes the Fishing Spiders. These are large spiders and your photo does not indicate scale, nor does your letter provide any indication of the size. We are uncertain of the exact identification, but we do believe the family is correct. Perhaps one of our readers will be able to provide more specific information.

Update from Eric Eaton
Hard to tell, especially without a size being given, but I would suspect this is actually a running crab spider in the genus Tibellus, family Philodromidae.  A close-up of the eye arrangement would also be telling…..