According to Garthwaite and Lawson this should be L. gracile. Unlike L. latum it is smooth instead of tuberculate.

Pretty interesting that they were here. Habitat was a dry creek bed that still had moist soil but no standing water. Not sure if it's seasonal in a normal year but unless we get some freak rain storms it seems like it'll probably get pretty toasty in the coming months. How do these isopods handle it? Like other Ligidium I've seen these only seemed to be in the rocky areas. Vegetation was oak / bay woodland, plenty of poison oak too.