Can Anyone Identify These?

[kevinfa]

Hey Guys,

I got this empty shell and it turn out it is not that empty! Can anyone tell me what is on its back? In fact there are 2 one small and the other close to the end is larger.

YouTube - Hermit Crab

[stkmach]

looks like the trunk on my conch, but it just stay on his shell? I dont know.

[returnofsid]

Does that "shell" on it's back have an opening at the tip? Looks like a Barnacle.

[Ninong]

Hi kevinfa,




Thanks for posting that very interesting video.

The mysterious creature appears to be a keyhole limpet. The top of the shell should have a small hole. My eyesight isn't good enough to tell if there is a tiny hole there or not. However, I was thoroughly confused by that black wormy critter that started showing itself at 1:40 into your video, so I asked for an expert's opinion.

Here is what Dr. Ron Shimek, a recognized molluscan expert, had to say after viewing your video:

The small snail on the tip of the larger shell appears to be a keyhole limpet. My guess is that the dark thing that comes out is a polychaete worm. If so it will be a symbiont of the limpet living in the snail's mantle cavity. It will come out and forage as you have seen for food. However, if something threatens the limpet (like a sea star) the worm will come out and bite the predator and defend its host. This relationship was first described for the NE Pacific snail Diodora aspera, and a scale worm, Arctonoe vittata that lives in the mantle cavity. I suspect such relationships are pretty common.