critter ID

[KRL1973]

You all were so helpful with my last question wanted to throw another one out there. Saw some little structures built out of bits of shell and wonder what builds it.

They were clustered in a dark rock crevice, about 1.5 to 3 inches long, didn't notice an obvious entrance/exit to them.

thanks
Ken

 

[Anti-Hero]

Hard to see in the pic.

 

[opisthobranch]

Hard to see but this is probably the Ornate Tube Worm Diopatra ornata. They make tubes of misc debris like that. Colonies of them can be quite large to the point of being landmarks like the "Worm Patch" at Point Lobos.

Clinton

 

[scubajunkee]

Yep, we usually call them "giant" nudibranchs because they get so big, but "rainbow" is another common name. As someone said, Dendronotus iris is the official name. The first picture shows him/her with a nice egg ribbon. You find them along the breakwater sand flats where those big fields of tube-dwelling anemones are, because that's what they eat. If you happen to come upon one getting ready to feast, it's unforgettable. The nudi climbs up the side of the tube, rears back, then plunges head-first into the anemone's tentacles, and of course the anemone pulls in and sucks the nudibranch with it, thinking "Ha! Food!" Then the nudibranch's radula starts going, and now the anemone is thinking, "Oh, crap! I am food!" But by then there's no way to get loose, and the anemone is done for.

One reason they're called rainbow nudibranchs is because they come in lots of different colors, as well. We've seen them deep red like yours, nearly-pure white, and all manner of in-between. They're also called giant nudibranchs because they can get upwards of 12" long.

Regards,
The Too-Much-Information Department

I was at the Breakwater last saturday and shot video of a dendronotus iris eating anemones. It's pretty cool. Check out the video here:

YouTube - Dendronotus Iris on the prowl

Ericson

 

[Chuck Tribolet]

Yep, we usually call them "giant nudibranch" because they get so big, but "rainbow" is another common name.

You are the first person I've ever heard call them "giant nudibranchs". "Rainbow
nudibranch" is the common name.

 

[pacificgal]

Awesome video, shared it with my cube mate next door.

 

[dwashbur]

You are the first person I've ever heard call them "giant nudibranchs". "Rainbow
nudibranch" is the common name.

It might be a Pacific Northwest thing, Idunno. I've seen them called Giant in various books, but those mostly deal with stuff up here in the Seattle/Puget Sound area. I usually say Dendronotus iris anyway just to prove I don't get tongue-tied saying it