Does anyone know what this is?

[Grahambo]

I found this in Costa Rica and do not know what it is.  I attached a couple pictures.  It is a small V shaped shell like piece.  I looks like it fits together with other similar type pieces but looks like it has detached.  It does not appear to be broken.  A Tico in Costa Rica told me it was part of a conch shell but I can't find anything that would suggest this is true.

Any help would be greatly appreciated.

[paul monfils]

You are correct. It does fit together with other similar pieces. Good observation! This is one of the 8 shell plates that join together to form the shell of a chiton. Chitons are a separate class of mollusks distinct from the bivalves and gastropods. They usually live attached to rocks or other hard surfaces, since their shell covers only the dorsal aspect of their body, and the soft tissues of their underside are exposed if they fall off the rocks. Some of them can curl up for protection if this happens however. The 8 shell plates are held together by a muscular band called the girdle, which encircles the outer edge of the animal. In some species it is smooth, on others bumpy or scaly or spiny. When the animal dies, this band of tissue decomposes, releasing the shell plates. They often wash up on the beach because chitons usually live in fairly shallow water.

http://www.snorkelstj.com/chitons.html

[Grahambo]

Thanks so much for the great and quick response.  I have been wondering about this for some time now.