Rudivastidae
Rudivastidae is a family of extinct marine bivalve mollusks belonging to the order Venerida. Fossils of Rudivastidae are found in Cretaceous to Paleogene rock formations, indicating their presence during the Mesozoic and early Cenozoic eras. The family is characterized by its thick, equivalve, and inequilateral shells, which are typically ovate or subquadrate in shape. The external surface of the shell often displays strong radial ribs, and the internal surface can exhibit crenulations along the ventral margin. The hinge structure is typically taxodont, with numerous small, chevron-shaped teeth. Rudivastidae are believed to have been infaunal burrowers, living in soft marine sediments. Their ecological role and precise taxonomic relationships are still subjects of ongoing research. Genera within this family include Rudivastis and other related forms. The disappearance of Rudivastidae likely coincided with major extinction events that affected marine ecosystems globally.