Subject: Colorful Nor Cal spider
Location: Oakland, California
April 21, 2013 3:44 pm
Met this one in the bathroom and noticed coloring I hadn’t seen before so went and got my camera. It was maybe 3/4” long. Didn’t seem aggressive or especially fast moving. Probably about 80F in the house.
This is one of the Ant Mimic or Ground Sac Spiders in the family Corinnidae, and we quickly identified it as Castianeira thalia on BugGuide. There are color variations with or without the red markings, and those individuals with the red markings are definitely more noticeable. All the reports of this species on BugGuide are from California. Though we have postings of other members of the genus, this might be a new species for our site.
Thanks very much for letting me know.