Placuna placenta
Encyclopedia
Placuna placenta, also known as capiz or windowpane oyster, is a bivalve marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 mollusk in the family of Placunidae
Placunidae
Placunidae, are a family of marine bivalves that are related to oysters and scallops. The family includes the specie Placenta placuna also called windowpane oysters or capiz in the Philippines, known for its translucency which are commonly used in shellcraft production.The family is closely related...

. Among the four species in the family, only the Placenta placenta has an outer shell translucent enough for commercial use.

Habitat

The distribution of the mollusk stretches from the shallows of the Gulf of Aden
Gulf of Aden
The Gulf of Aden is located in the Arabian Sea between Yemen, on the south coast of the Arabian Peninsula, and Somalia in the Horn of Africa. In the northwest, it connects with the Red Sea through the Bab-el-Mandeb strait, which is about 20 miles wide....

, to around India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, then Malaysia to the southern South China Sea, and around the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

. These can usually be found in muddy or sandy shores on bays, coves and lagoons to a depth of about 100 m (328.1 ft). Windowpane oysters are also cultivated in some areas. Like other bivalves they consume plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...

 filtered from the water passing through its slightly opened shell; shut closed if above water during low tide.

Anatomy

The almost-flat concave shells of the capiz can grow to over 150 mm (5.9 in) in diameter reaching maturity between 70 millimetre; securing the shells is a V-shaped ligament
Ligament
In anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...

. Male and female oysters are distinguished by the color of the gonad
Gonad
The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, spermatozoon and egg cells are gametes...

s. Fertilization is external and larvae
Larvae
In Roman mythology, lemures were shades or spirits of the restless or malignant dead, and are probably cognate with an extended sense of larvae as disturbing or frightening...

 are free-swimming like plankton for 14 days or attached to surfaces via byssal thread during metamorphosis
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...

 eventually settling in the bottom.

Uses

These oysters are edible but valued more for the shell which are used as a raw material in the manufacture of glue, chalk, varnish, etc. The translucent capiz shells are commonly used in window panes in India, the Philippines and other Asian countries. They are a cheaper alternative to glass and readily abundant. Windowpane oysters are also pearl
Pearl
A pearl is a hard object produced within the soft tissue of a living shelled mollusk. Just like the shell of a mollusk, a pearl is made up of calcium carbonate in minute crystalline form, which has been deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other...

 producers which are commercially exploited.

The primary exporter of products made from the shellfish is the Philippines where it is known locally as kapis, used in the manufacture of decorative items like chandelier
Chandelier
A chandelier is a branched decorative ceiling-mounted light fixture with two or more arms bearing lights. Chandeliers are often ornate, containing dozens of lamps and complex arrays of glass or crystal prisms to illuminate a room with refracted light...

s and lampshade
Lampshade
A lampshade is a fixture that covers the lightbulb on a lamp to diffuse the light it emits. Conical, cylindrical and other forms on floor-, desk- or table top-mounted as well as suspended lamp models are the most common and are made in a wide range of materials. The term can also apply to the...

s to kitchen utensils like mats, trays and bowls.
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