Identify this weird tidepool creature?

[MikeS]

My parents took a trip to Hawaii (Big Island, if it matters), and brought back lots of pictures. One of them they couldn't identify, and they agreed to let me post it here to see if the SDMBers could identify it:

Bizarre creature

The largest of the creatures were about two inches long, for scale. Anybody have any thoughts?

[Sailboat]

From that picture, it's hard to tell whether we're seeing legs or just striations on the shell. If it's not legs, perhaps they are limpets?

Sailboat

[Sailboat]

After more Googling around, I wonder if they're some sort of chiton? I didn't see any pics that looked enough like them to be worth posting. But it's got to be some overall kind of creature, and it ain't a fish...so far limpet or chiton are my best guesses.

Sailboat

[Cervaise]

Definitely looks like a chiton to me but it's hard to tell. If that's a digital picture, any way you could zoom and crop the original to make one of the critters easier to see?

[MikeS]

No, she says that the "fringes" (if they weren't actually legs) were separate, not some sort of radial striation. She wasn't sure if they were using the "legs" to move or if there was some other form of locomotion involved.

Also, the "shell" wasn't hard like a crab shell or a scallop -- more like a fish's scales, if you had to compare it to something.

[MikeS]

The maximum resolution we have is 1024 x 768; it's on Flickr here.

[Tamerlane]

Shingle urchin ( Colobocentrotus atratus ). It has sharply reduced spineage, due to its intertidal habitat, hence its peculiar appearance. You can scroll down to see it here:

http://www.coralreefnetwork.com/sten...ns/urchins.htm

- Tamerlane

[MikeS]

Originally Posted by Tamerlane

Shingle urchin ( Colobocentrotus atratus ). It has sharply reduced spineage, due to its intertidal habitat, hence its peculiar appearance.

That's the one. Many thanks!

[ouryL]

Weird ass sea urchin ‘uke‘uke, pdf from The Waikiki Aquarium