Placuna

Placuna is a genus of marine bivalve mollusks in the family Placunidae, commonly known as windowpane oysters. The most well-known species within the genus is Placuna placenta, the windowpane oyster or capiz oyster, noted for its very thin, translucent shells that can be cut into sheets.

Distribution and habitat of Placuna placentas species and relatives are in warm, shallow coastal waters of the Indo-Pacific region. The shells are most associated with areas around the Philippines, Indonesia, and neighboring Southeast Asian coasts, where they inhabit sandy or muddy bottoms often near seagrass beds and in neritic zones. They are sessile as adults and function as filter feeders, drawing in microscopic particles from the water.

Description and use: The shells produced by Placuna species are extremely thin and translucent, often ranging from pale brown to creamy in color. When processed, these shells yield capiz sheets that have long been used for decorative purposes. Capiz sheets are shaped into windowpanes, lampshades, screens, and various craft and jewelry items. In many places, the term capiz refers both to the shells themselves and to the translucent material derived from them.

Ecology and life history: Like other bivalves, Placuna species are filter feeders and reproduce through aquatic broadcast spawning, releasing eggs and sperm into the water column. They contribute to coastal ecosystems by filtering water and serving as habitat for small organisms.

Conservation and trade: Capiz shells have historically been a significant regional trade commodity, particularly in the Philippines. In some areas, harvesting and trade are regulated to prevent overexploitation and to protect coastal habitats, though local pressures from habitat degradation and fishing can affect populations.