Cardiniidae is an extinct family of marine bivalves, most diverse and abundant in the Lower Jurassic of Europe. The shells are robust and equivalve, with an oval to subtrigonal outline, strong concentric growth lines, and a thick hinge plate bearing massive teeth. They lived as shallow burrowers in muddy or sandy seafloors, filter-feeding on suspended particles. They are characteristic, and locally rock-forming, components of the Lower Lias of northern England.