The Agua Nueva Formation is a geologic formation in Mexico. It preserves fossils dated to the latest Cenomanian and Turonian ages of the Cretaceous period. It consists "predominantly of alternating fossiliferous, organic matter-rich, laminated, dark gray limestone and non-laminated, organic matter-poor limestone in decimeter-thick beds (10 to 30 cm) with occasional centimetric beds (5 cm) of brown shale that show no apparent internal structures." The formation is noted for its qualities as a Konservat-Lagerstätte, with notable finds including the plesiosaur Mauriciosaurus, the mosasaur Yaguarasaurus and sharks Ptychodus and Aquilolamna.
It appears to have been deposited on the upper part of a shallow continental shelf.
Based on Amalfitano et al (2020):