A typical left valve showing the anterior sulcus and the incurvature. A significant species that strongly resembles G. arcuata except for its smaller size. This species is one of the earliest known Gryphaeas and Hallam and Gould, 1975 [11], and Hallam, 1982 [10], suggest that it migrated from the Arctic into Europe, giving rise to the earliest European Gryphaea near the base of the Lias, where it replaced Liostraea as a consequence of environmental change. It is therefore postulated as the ancestor of the two European evolutionary lineages.