How to Identify Mollusk Shells
The phylum Mollusca contains over 100,000 identified species, making it one of the most diverse and largest phyla of animals, next to arthropods. They are found in almost every ecosystem from the tropical rain forest to rivers, seas and oceans. Most mollusks have an open circulatory system, and while some species are slow moving, others are active predators. You can take several steps to identify a mollusk shell.
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Instructions
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Identify where the shell was found. Geographic locations offer different mollusk shells. Chitons, for example, are often found in rocky areas within intertidal zones such as tide pools.
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Determine whether the shell has a hinge. The shells of bivalves comprise two shells, hinged together with a ligament forming one shell. An example of a bivalve shell is the razor clam.
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Determine how many plates the shell contains. Chiton shells contain eight overlapping plates (valves) that usually come apart when washed up on shore.
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Determine if the shell looks like a tusk or tooth. Scaphopod shells contain tusk-like arced cones with openings at both ends. Relatively small and light colored, scaphopods can be difficult to detect on beaches.
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Identify the shell's marine mollusk group. There are several types of mollusks in each class. The major groups of mollusks containing shells include gastropods or univalve (not hinged) such as abalone, conches and limpets; bivalves (hinged) including scallops, clams, oysters; and cephalopods. Other groups include scaphopods (tusk shells), chitons and monoplacophores (once thought to be extinct but found in Costa Rica in 1952).
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Tips & Warnings
Consult a book or website on marine mollusks once you have examined your shell.
References
Resources
- Photo Credit Conus betulinus image by Stokholm from Fotolia.com
