An intriguing decorator crab found under a rock in the low intertidal zone at Cape Arago, OR, on 11 May 2012. It's a Foliate Kelp Crab (or Mimicking Crab), Mimulus foliatus.
This species ranges from Alaska to southern California. It should occur at Bodega Head, but I haven't encountered it yet. Has anybody else?
Note the broad carapace with wing- or leaf-like extensions or flanges along the sides.
Decorator crabs often attach objects to their shells for camouflage. In the photos, look for the plant material and red algae attached to its rostrum, or "nose."
After turning over the crab to see its underside, we realized that this Foliate Kelp Crab was a female carrying eggs. In the photo below, look at the small purple eggs attached to her abdomen.
It's not uncommon to find bryozoans or sponges growing on the shells of Foliate Kelp Crabs. See below for a close-up of both (bryozoan in white/gray, sponge in yellow) visible on the corner of her shell.
P.S. You may be familiar with a plant by the name of Mimulus (also known as monkeyflower). There are two species on Bodega Head: Mimulus aurantiacus and M. guttatus. More about them later!