British Permian Ostracoda are restricted to Upper Permian sedimentary rocks deposited along the western margin of the Anglo-European Zechstein Sea (Fig. 1). Ostracoda have been recorded in carbonates deposited during the basal marine phase of three evaporite cycles in both the Yorkshire and Durham provinces. West of the Pennine Ridge, a smaller marine basin known as the Bakevellia Sea (named after a marine bivalve genus) has been interpreted as a minor extension of the Zechstein Sea, coeval with the first evaporite cycle. Rocks deposited in the Bakevellia Sea (Fig. 1) have yielded poorly preserved Ostracoda.