pseudolamellibranch ctenidium

The term "pseudolamellibranch ctenidium" refers to a specific type of gill structure found in certain bivalve mollusks, such as scallops and oysters. The ctenidium, or gill, in bivalves is a respiratory organ that has also adapted for filter-feeding.123

In a pseudolamellibranch ctenidium, the gill filaments and lamellae are more securely joined than in simpler filibranch gills, but an inherent sorting mechanism for food particles may still exist in some species. This structure is characterized by the filaments being vertically aggregated into folds, significantly increasing the total surface area for gas exchange and food collection. This adaptation allows these bivalves to efficiently extract oxygen from the water and filter out food particles.453