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Pinnidae

life science Maturity 11-13 Next article →

Pinnidae are a family of large saltwater clams.

People sometimes call them pen shells. These clams live in the ocean. Their shells have a long and triangular shape. The shells are quite fragile. One end is very pointy. The clam uses a byssus to stay in place. A byssus is a thread that anchors the clam in sand or mud.

Fine sea silk threads
Fine sea silk threads

The inside of the shell is very shiny. This shiny layer is called nacre. It is found near the umbos, which are the pointed ends. These clams are very useful to people. Some species are fished for food. People in Japan and Mexico eat them. In Polynesia, people carve the shells into art. They even use large shells as plates.

Some clams make pearls. These pearls have moderate value. A clam called Pinna nobilis is very special. For many centuries, people used its byssus to make cloth. They made gloves, shawls, and cloaks. This sea silk has a golden color. It was very valuable to people in the past.

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File:Fine sea silk threads.JPG
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