Nepedia
Back to Discover
Fluent Reader
🧬

Pinnidae

life science Maturity 11-13 Next article →

Pinnidae are a family of large saltwater clams.

Some people call these clams pen shells. They are marine bivalve molluscs. This means they have two shells. They belong to the order Pteriida. These clams live in the ocean. They are very important to many parts of the world.

Fine sea silk threads
Fine sea silk threads

These clams have a unique way of living. Their shells are long and have a triangular shape. The shells are quite fragile. One end is very pointy. This end is called the umbo. The clam uses a byssus to stay in place. A byssus is a thread that anchors the clam in sediment. This helps it stay in the sand or mud.

Fine sea silk threads
Fine sea silk threads

The inside of the shell is very beautiful. There is a thin layer of nacre near the umbos. Nacre is a shiny, iridescent material. It catches the light in many colors. Some of these clams also produce pearls. These pearls have a moderate value. They are a special gift from the sea.

Fine sea silk threads
Fine sea silk threads

Humans have used these clams for a long time. The Pinna nobilis species is very famous. For many centuries, people used its byssus to make clothing. This material is called sea silk. It has an attractive golden hue. People used it to make gloves, shawls, stockings, and cloaks. These items were greatly valued by the ancients.

Fine sea silk threads
Fine sea silk threads

Many different groups of clams exist in this family. There is the genus Atrina, which has 40 species. The genus Pinna has 27 species. There is also Streptopinna, which has only one species. People eat these clams in Japan and Polynesia. They are also eaten on the west coast of Mexico. In Polynesia, people carve Atrina vexillum shells into art. They even use large shells as plates.

Fine sea silk threads
Fine sea silk threads
285 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (1)
File:Fine sea silk threads.JPG
Fine sea silk threads.JPG
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.