Sorry I didn't get better pictures, Scott. This isopod lives in the sand under the wrack at the high tide line. Garthwaite and Lawson reported that it was found at Pt. Pinole. Wonder if we could turn it up at Albany Bulb or Radio Beach...
Watched two small males harangue a GIANT female. This was one of the males.
Not really getting the flattened tibiae and metatarsi thing they speak of on BugGuide. Legs of C. armatus and C. angularis look pretty much this same to me.
Maybe Niambia capensis