Very strange snail or something else?

[TeeJay87]

Can someone please help me identify this? Would have hitchhiked on my TBS live rock two years ago, but this is the first time I’ve noticed it. I would say it’s about a quarter of an inch. This is its underside (it was stuck on the back side glass at first, but I removed it and it is resting on the bottom glass for this picture). It didn’t really look like a normal snail shell, but has a hard surface on the creature’s back side that looked rock like. Also, it isn’t sucking its body into its “shell”, which is what a snail would typically do when not attached to anything. Any ideas?

 

[vaguelyreeflike]

Can you get better photos from other angles? Almost looks like a chiton

 

[ISpeakForTheSeas]

The pic looks like the hinge of an Ark Shell Clam (Arca genus).

 

[TeeJay87]

Can you get better photos from other angles? Almost looks like a chiton

Unfortunately, this is the only picture I took. It was my first time seeing it in over 2 years of having the tank, but I will keep an eye out for it and snap more pictures.

 

[TeeJay87]

The pic looks like the hinge of an Ark Shell Clam (Arca genus).

It didn’t have any lines on the shell like I’m seeing in google image search for Ark Shell Clams.

 

[ISpeakForTheSeas]

It didn’t have any lines on the shell like I’m seeing in google image search for Ark Shell Clams.

Yeah, in that case I'd agree with the above - pics from different angles would be needed. That said, I'd be surprised if it's not a bivalve of some variety, so I'd guess it's a harmless filter feeder.

 

[TeeJay87]

Just to clarify what the picture is showing. What it uses to suction to the glass is what we are looking at in the picture. The creature’s back and side are resting on the bottom of the glass (I rolled it over like that). I think it’s “head” is on the right side and it looks to have 5 sets of 2 ”feet” as you look left of the ”head”.

 

[ISpeakForTheSeas]

Just to clarify what the picture is showing. What it uses to suction to the glass is what we are looking at in the picture. The creature’s back and side are resting on the bottom of the glass (I rolled it over like that). I think it’s “head” is on the right side and it looks to have 5 sets of 2 ”feet” as you look left of the ”head”.

Yeah, I see what you're saying - what it looks like to me is a patterned hinge on the back of a bivalve shell that has pieces curving down over the hinge like in the links below:

https://www.aphotomarine.com/images/marine_bivalves/bivalve_arca_imbricata_01-02-16_6.jpg

https://www.aphotomarine.com/images/marine_bivalves/bivalve_arca_imbricata_01-02-16_7.jpg

I don't know a species with that particular pattern to it though.