Permian productidina of Britain and Malaysia
The British Permian Productidina have not been revised in detail since 1858. In the present study some 2000 specimens from 29 localities in north east of England have been collected and prepared in the laboratory and used together with museum collections. The fauna consists of four species of Strophalosia, one new species of Eostrophalosia, six species of Heteralosia (four new), three species of Craspedalosia (one new), two species of Howseia, four species of Horridonia (one new) and two species of Spinohorridonia new genus. The Strophalosiacea and Horridoniinae are divided according to a new classification produced in this research. British Permian productidinid species are often strongly variable. Some variants suggest possible sexual dimorphism while others are probably of ecological forms. The fauna as a whole is unique and exclusive to the Upper Permian Zechstein Sea. The British Permian fauna shows major radiation periods during the early EZla Ca and early EZlb Ca. In conjunction with these radiations, the Productidina become divided into two distinct assemblages, marking two biozones introduced in this thesis, the Horridonia horrida and Strophalosia excavata biozones. Little is known of the Malaysian Permian Productidina. They comprise one species each of Strophalosia, Craspedalosia, Institella, Antiquatonia, Reticulatia, Echi- noconchus, Linoproductus, Siepanoviella, Striatifera, Liosotella (with new species), Marginifera?, Paucispinifera, Retimarginifera (with new species) and Costispinifera, two species of Dictyoclostus, Waagenoconcha and Echinauris and three species of Cancrinella. Lower Permian productidinids are associated with Artinskian fusulines and show links with the South Tethyan cold water fauna. Upper Permian producti dinids contain a mixture of North Cathaysian elements and the warm South Tethyan lyttoniid fauna. Variation occurs within some of the Malaysian species, but owing to lack of material, no final deductions can be made. Similarly, although significant differences are observed in Malaysian productidinid distributions, tabulation of biostratigraphic zonation is left until more data is available.