Variability in Amoria praetexta (Reeve, 1849) (Volutidae)

The holotype of Amoria praetexta (Reeve, 1849) British Museum is compared with specimens of this species from across the known range within the shallow waters of the southern Exmouthian Subprovince. The name of the type location is clarified as the Muiron Islands and corrected from “Long Island”. Amoria praetexta is unusual considering the degree of variability in the number of columella plaits, ranging from three to four within some populations. The spire of A. praetexta is also variable in form, ranging from angulate to mamillate and blunt. This high plasticity in form mirrors other Amoria species such as Amoria turneri Gray, 1834 and Amoria qii Zheng and Maxwell, 2026. This is in contrast to the stability of other species such as Amoria stevencantamessai Zheng and Maxwell, 2026 and Amoria paulcoxi Zheng and Maxwell, 2026. In demonstrating the high degree of morphological plasticity in single populations, A. praetexta can be used to provide guidance when refining species boundaries in other highly polymorphic species such as Amoria volva (Gmelin, 1791).