Global Boundary Stratotype Section and Point
The base of the Moscovian is close to the first appearances of the conodonts "Declinognathodus donetzianus" and "Idiognathoides postsulcatus" or otherwise the fusulinid "Aljutovella aljutovica". Because the fusulinid species are regionally different, they can not be used for worldwide correlation. A Global Boundary Stratotype Section and Point for the Moscovian stage has yet to be defined (2008). A proposal is to use the first appearance of the conodont "Diplognathodus ellesmerensis", but since the species is rare and its evolution relatively unknown, it has not been accepted yet.