Western Pacific Permian marine invertebrate palaeobiogeography

Data matrices of the presence/absence occurrence data of brachiopod genera from faunal stations throughout the western Pacific region for the Asselian-Tastubian, Sterlitamakian-Aktastinian, Baigendzhinian-Early Kungurian and Kazanian-Midian time slices of the Permian Period have been analysed by cluster analysis, non-metric multidimensional scaling and principal coordinate analysis. An evolving pattern of provincialism is recognised for the Permian of the western Pacific with four provinces (Indoralian, Himalayan, Cathaysian and Verkolyma) for the Asselian-Tastubian, six (Austrazean, Westralian, incipient Cimmerian, Cathaysian, Sino-Mongolian precursor and Verkolyma) for the Sterlitamakian-Aktastinian, seven (Austrazean, Westralian, Cimmerian-with the Sibumasu and Himalayan subprovinces-Cathaysian, Sino-Mongolian and Verkolyma) for the Baigendzhinian-Early Kungurian, and three (Austrazean, Cathaysian and Verkolyma) for the Kazanian-Midian time slice. The changing pattern of provincialism is best understood in terms of the evolution of the epicontinental Sino-Mongolian Sea in the north and the rift-drift history of the Cimmerian continental blocks in the south, set against a backdrop of climate amelioration during the Permian.