Atrina maura, commonly known as the black pen shell or the mourning pen shell, is a species of large marine bivalve mollusk. It is a member of the family Pinnidae, which are commonly known as pen shells. These bivalves are characterized by their elongated, flattened shells with a narrow, pointed end. Atrina maura is a fascinating and important species, playing a significant role in marine ecosystems.
Description & Characteristics
Atrina maura is a large bivalve, reaching a maximum size of around 40 centimeters in length. Its shell is typically black or dark brown, often with a velvety texture. The shell is also somewhat fragile and can be easily broken. The interior of the shell is pearly and iridescent. Atrina maura has a distinctive byssal thread, which is a strong, fibrous strand used to anchor the mollusk to the substrate. The byssal thread is often quite long, extending several centimeters beyond the shell. This thread is a fascinating adaptation, allowing the pen shell to maintain its position in the sometimes-turbulent marine environment.
Habitat and Occurrence
Atrina maura is found in a variety of habitats, including rocky reefs, sandy bottoms, and seagrass beds. It is a common species in the Mediterranean Sea, the Atlantic Ocean, and the Indian Ocean. Atrina maura is typically found in shallow waters, ranging from the intertidal zone to depths of around 50 meters. It is primarily found in the neritic zone, which is the coastal zone of the ocean, characterized by its shallow depths and the influence of sunlight. This zone is highly productive, supporting a wide variety of marine life, making it an ideal habitat for Atrina maura.
Taxonomy
Atrina maura belongs to the Class: Bivalvia, Order: Ostreida, and Family: Pinnidae. Bivalves are a class of mollusks characterized by their two-part hinged shells. Ostreida is an order within the Bivalvia that includes oysters, scallops, and other related bivalves. The family Pinnidae, to which Atrina maura belongs, is known for its elongated, flattened shells, commonly referred to as pen shells.
Feeding
Atrina maura is a filter feeder, meaning it obtains its food by filtering microscopic organisms from the surrounding water. It accomplishes this using its gills, which have a large surface area and are covered in cilia. The cilia create a current that draws water into the mantle cavity, where the gills capture food particles. Atrina maura is an important part of the marine food web, consuming large amounts of phytoplankton and other small organisms. This filtering action also contributes to the clarity of the water, benefiting other organisms in the ecosystem.
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