The Mangrullo Formation is an Early Permian (Artinskian) fossiliferous geological formation in northeastern Uruguay. Some authors alternatively group it together with the and the as the three subdivisions of the , in which case it is referred to as the Mangrullo Member. Like the correlated formations of Irati and Whitehill, it is known for its abundant mesosaur fossils. It also contains the oldest known Konservat-Lagerstätte in South America, as well as the oldest known fossils of amniote embryos.