Sunday, April 26, 2009

Antrodiaetus pacificus

Last weekend I was fortunate enough to stumble upon one of the Mygalomorph spiders native to Oregon. (For those not in the know, Mygalomorphs are the more "primitive" spiders that include tarantulas and are seldom encountered in temperate climes.)

I knew that at least several species of Antrodiaetus were found in Oregon, but I had heard they were almost impossible to find because the entrances to their burrows are so well-camouflaged. I found this one by pure dumb luck, lifting a few random pieces of dead wood to see what was underneath.

(For more pictures, as well as larger versions, please visit my gallery. Photo credit goes to FunnyLori, camera provided courtesy of Rabscuttle.)

I brought her to a few entomologists I know to confirm the genus as well as the fact that she's a mature female. They told me that mature specimens can live up to five years and that there's a distinct possibility she's gravid. My own research confirmed the species as A. pacificus - the most convincing feature is the single tergite present on her abdomen. Females of this species have one whereas males have three.

This girl is currently housed in a mini-habitat based on suggestions made by the entomologists. I'm going to watch it for a turret (burrow entrance) and offer her prey in a couple days. With luck, I'll look in one day to see dozens of her miniatures running about searching for springtails to eat.


Flip said...


We found a few of these two summers ago. A friend of ours Gave us some tulip bulbs. As we were breaking them apart 4 of these were revealed. They scared the heck out of us as they acted very agressive (took a defenive posture baring big fangs! not the palps)
It was a hot day and they soon died very soon after being exposed to the sun. I wish I had kept them as a specimen as I have never ran across them since. They were a very imressive spider. Mine were a more black color in the body/legs (yours is more brown. the Abdomen was about the same color as the one you have pictured

jennifer said...

We seem to be having an infestation of this type of spider (although I'm guessing the one I currently have alive is a male as it has three spots) but ours are the darker variety as mentioned in the previous post. Over the past two nights we've captured 1 and "disposed" of probably 7 or 8. If they are as shy as you make it seem, do you have any idea what could be causing them to all of a sudden be coming out? One was found in our garage on the floor and the rest were crawling across the back patio. I haven't seen any webs around our house other than those of the typical garden spider. Should I be worried about these spiders being poisonous?

Thanks for any info!

Jen in salem