Mystery Mollusk

[LCDRDATA]

My wife spotted this little guy moving along the bottom front of the tank this morning, and we're trying to figure out what he might be:

http://reefcentral.com/gallery/data/500/194807mystery_mollusk.jpg

You can clearly see his mouth/radula and one of his two antennae (he did have both, the second just isn't visible in this shot). Note that really his foot was pretty much a uniform gray; the green spots are algae on the glass. Here's another picture pulled a bit back for some size perspective (empty astrea/margarita snail shells) - he's in the lower left:

http://reefcentral.com/gallery/data/500/194807mystery_mollusk_2.jpg

We got a brief look at the top side, which was a somewhat darker blue/gray, and about the same color as the underside farther back. It looked like there were some hairlike projections along its dorsal side, mainly toward the back. Unfortunately he only moved onto the sand where we could see that side for a moment, then he was back on the glass.

Any ideas what it might be? We were thinking perhaps a nudibranch of some kind, except that this is the first time we've ever seen this guy, and it's been probably two months since we added anything he might have hitched a ride in on. The other thought was perhaps it might be a snail that some hermit crab had pulled out of its shell - we have astrea, turbo, trochas, and margarita snails of roughly the appropriate size. Mitigating against that, though, was that there was no apparent damage, unless the "hairs" were the shell attachment ligaments, and even there we didn't see any clear evidence of trauma.

Finally, my wife spotted this guy just after turning some lights on at about 5:30 this morning. We check out the tank fairly regularly after the lights are out, but at night (say around midnight). And we've never seen this guy before. Any takers on a tentative ID? Thanks.

[anomie]

It looks like a stomatella but can't say for sure since I can't see it's back. They are very reef safe and a good guy to have in the tank. http://www.melevsreef.com/id/stomatella.html

Good luck. :)

[pagojoe]

Yes, it's a Stomatella, but ID'ing snails from the bottom of the foot is not the way to go as a general rule. Most snails look pretty much the same from the bottom. The long foot, long antennae, hairlike projections, and the shell that covers half of it's body (the front half, in the top pic) all say this is a Stomatella, but 99.99% of the time it's wasted effort to take photos of the bottom of a snail's foot. Any other view is potentially helpful, but a straight-down dorsal view is best.

Cheers,


Don

[LCDRDATA]

After looking at your information (and some additional articles online) I believe that it is a stomatella. I absolutely agree that the photo angle I provided is probably the single least useful view; unfortunately it's the only one I could capture. Luckily, though, between that shot - limited as it might be - and what I was able to see and describe we've been able to come up with a positive ID. Now I just have to keep an eye out for it to see it again. Still don't have any idea where it came from, other than "must have hitched a ride on somebody." Thanks for your help!

[LCDRDATA]

Well, he showed up again and I was able to get a better angle on the little stomatella (with the reflection off the corner, he looks like multiples of himself):

http://reefcentral.com/gallery/data/500/194807mystery_mollusk_identified_-_stomatella.jpg

[Reefmad97]

It looks like a stomatella to me, very beneficial to a reef tank. But on the first photos it looked like a nudibranch. I have a pure black one in my tank.