Plicatostylidae is a family of extinct large-sized epifaunal marine to brackish bivalves that inhabited Europe, Asia, Africa and America during the Jurassic, tought they survived until the Eocene.

[2][3] They represent large reef builders, analogues to the younger Rudists and modern Crassostrea, and less extent to Tridacna.

[4][5] They developed in large reef systems like modern Crassostrea, but in warm, shallow seas, with some bioherms attaining lengths over 60 m and thicknesses of 3-5 m.[2][4] They were rapid growers, with their shells often made of aragonite, leading to massive shell accumulations that shaped the sea floor, known as the "Lithiotis Facies".

[4] Plicatosylids were notably widespread in the Lower Jurassic, specially within the Sinemurian-Pliensbachian, with significant occurrences in Tethyan and Panthalassan margins, from areas in Italy (Rotzo Formation of the Trento Platform, Apennine Carbonate Platform), Slovenia (Podpeč Limestone), Montenegro (Budoš Limestone) and parts of North America (e.g., Oregon).

Aganane Formation & Tafraout Group) they are found in association with Corals, suggesting a different ecological context during their later survival.