Philodromus - The Running Crab Spider
In which I finally identify a cool spider from Arizona
_Philodromus sp._ - a “Running Crab Spider” on the trunk of a Palo Verde Tree. Look at the row of tiny little eyes on the spider’s face…very cool.
On May 29, 2004, in South Tucson, Arizona, I made a visit to the local gardening store. I would stop by about once a week or so, partly to look at their plants…but mostly to look at the insects on the plants.
On this particular occasion, I found a lovely spider on the vertical trunk of one of their Palo Verde Trees. The spider was 2”, perhaps 3” in diameter, and had a very flat appearance. It was so large that I had trouble getting the entirety of the spider into a single photograph.
I’ve looked back at those photos many times over the years. I figured that this spider was a “Flatty” - a “Wall Crab Spider”, a member of the family Selenopidae.
But it just didn’t look quite right. In this image, from Eric Eaton’s wonderful “Bug Eric” blog, you can see that his spider’s body form, and the way it holds its legs, and just the general “feel” of the spider, is different than the spider in my photos.
So what type of spider is this?
Then Fortune smiled. My wife was rummaging around in the bookcase for a book about Colorado birds when she came across a spiral-bound book. It was a copy of “Spiders of North America”.
It turns out that I had purchased the book way back in 2007…then promptly put it in the bookshelf and forgot about it!
It is not clear to me how one might do such a thing…but I obviously did.
So it’s been a bit like Christmas morning here, with me going through old, previously-unidentified spider photos such as these ones.
As near as I can tell, the flat mystery spider is a member of the Philodromidae, the “Running Crab Spiders”. I’m thinking it is one of the species in the genus Philodromus.
And I’m having a wonderful day, listening to the wind howl outside and identifying old desert spider photos.
Sources:
Cushing, Paula and Ubick, Darrell. 2009. Spiders of North America: An Identification Manual. American Arachnological Society; Spi edition (April 1, 2009). Spiral-bound : 377 pages. ISBN-10 : 0977143902. ISBN-13 : 978-0977143900. Not sure why the publication date on this is 2009 when I purchased the book in 2007…maybe the citation data is for a later edition?