FOUL MONSTERS OF THE NOT-SO-DEEP!

Nanaimo dorid (Acanthodoris nanaimoensis)

Maybe this is getting a little out of hand. I mean, when searching for nudibranchs generally entails getting up before dawn, driving for over an hour, and wading around in ice cold water, and I just decide I need to go do it on a whim, even though the tide isn’t even especially low, then clearly I have lost it. This morning was Duxbury Reef, just north of Stinson Beach in Bolinas, CA. Nice big shale reef with plenty of pools, or at least there would be at a decent low tide. As it was, I spent the first 30 mins putzing around the first set of pools I saw that seemed decently far out, and then had to retreat to higher ground as the tide sloshed at me threateningly. While I was out there, though, I did see a few things, notably the handsome fellow above, which I’m almost certain is Acanthodoris nanaimoensis. I didn’t see the red rhinophores, but I think it may have retracted them in fear. It was about 3-4 cm long. Nanaimo is a town on Vancouver Island, and you pronounce it nah-NIGH-mo, apparently (why do I feel the urge to look these things up…). I also saw several opalescent nudibranchs and Doto amyra, and one tiny Triopha maculata, but none of them were present in the kinds of numbers I’ve seen at Bean Hollow. Maybe I need to check it out when the tide is lower.

Saw two odd arthropods as well. The first was a sea spider, an exceptionally strange creature in the order Pycnogonida, possibly related to the land spiders we all know and love. The first time I saw one I wasn’t able to identify it. I was just peering into a pool with my cap breaking the surface when some weird basal pattern matching neural subroutine yelped “LEGS!” and I snatched it up. Higher level functions than wrote it off as a piece of detritus, since it seemed to be all legs, but then it moved, and my cerebellum returned to its corner in shame. This time I knew what I was seeing so I got it and tried to take a picture. As you can see, that didn’t work out so well (each leg was about 5mm, tops). Anyway, now at least have a name for it. Incidentally, sea spiders are predacious or parasitic, and some have been observed feeding on nudibranchs. I found this guy next to the Nanaimo, but not on it. I’ll keep an eye out for them sucking vital nudibranchial juices in the future. (Also, look how incredibly evil the larger, deep-sea varieties are!)

The second weird arthropod was this guy:

Unknown isopod (Idotea sp?)

I found it on a piece of sea grass, which its two antennae thingies lined straight up with its body so it looked like very much like a discolored portion of the plant. If it was green I would never have seen it. I’ve yet to reach that murky depth of invertebrate dorkdom where they “know” their isopods, but judging by the pictures on this guide, I’m guess it’s in the genus Idotea. That bug box is about 3cm to a side.