red-striped acorn barnacleBalanus pacificus
Amazingly, this is an arthropod. Can you believe? This is a big specimen at 32mm along its base. I admit to bringing it home from the commercial boat loading dock parking lot and am not sure what to do with it now. Is it still alive? I'm tempted to get a bucket of ocean water to see if it'll open up. I'm making a huge guess as to its ID since there's not a lot of online information for barnacle species. Mainly, because of its size, I'm thinking it must be a Megabalanus. I did find a wonderful marine blog from across the pond while searching for the ID: Jessica's Nature Blog.
ps 11/30/13 - I originally posted this as Megabalanus californicus, but the variation of reported sizes, 30 mm to 60 mm, has continued to bother me. So, I'm going with the smaller locally found Balanus pacificus as listed in The Beachcomber's Guide to Seashore Life of California. Part of my problem for tracking an ID is that a couple of my favorite sites (like Walla Walla University and Washington State University) are too far north to include this pretty barnacle, which reportedly ranges from Chile and Peru to Monterey Bay.
