Gryphaeidae

Gryphaeidae is a family of marine bivalve molluscs, commonly known as true oysters. These filter feeders are characterized by their irregular, often elongated shells, which are typically cemented to a hard substrate. The family includes several important genera such as Gryphaea and Lopha. True oysters are found in marine environments worldwide, inhabiting a range of habitats from shallow coastal waters to deeper ocean floors.

Unlike some other bivalves, gryphaeids often exhibit a distinct asymmetry in their shells, with the lower valve being larger and more convex than the upper valve. This morphology aids in their attachment and stability. Their diet consists of plankton and other small organic particles suspended in the water column, which they filter through their gills.

Gryphaeidae plays a significant ecological role in marine ecosystems, contributing to water clarity and providing habitat for other organisms. Fossilized remains of gryphaeids are also common, offering insights into ancient marine environments. Economically, some species within this family are commercially harvested for food and as sources of pearls. The classification within Gryphaeidae is based on shell morphology, hinge structure, and genetic analysis.