Wuchiapingian (early Lopingian, Permian) global brachiopod palaeobiogeography: a quantitative approach

A global presence/absence database of 212 Wuchiapingian (early Lopingian, Permian) brachiopod genera from 30 stations is analysed by cluster analysis, nonmetric multidimensional scaling and minimum spanning tree to document the global palaeobiogeographical patterns. Five core groups are revealed by the quantitative analysis and interpreted as representing five marine biotic provinces. They are the Cathaysian (tropical), Western Tethyan (tropical), Himalayan (warm temperate), Austrazean (cold temperate) and Greenland - Svalbard Provinces (cold temperate). The Cathaysian Province is composed of many isolated or semi-isolated islands situated in the Palaeotethys, whereas the other four provinces occurred mainly on the continental shelves of Pangea: the Western Tethyan Province along the western coast of the Palaeotethys, the Himalayan Province on the northern margin of Gondwanalan d, the Austrazean Province along the southeastern margin of Gondwanaland, and the Greenland - Svalbard Province on the northern margin of Pangea. In addition, nonmetric multidimensional scaling helped to identify key biogeographic determinants: latitude-related thermal gradient appears to have accounted for most of the variance in the data; geographic distance and ocean circulation may have also played a major, but subordinate, role in the delineation and/or enhancement of some of the provinces. Comparison with Early and Middle Permian global marine provincialism indicates that marine biotic provinces had significantly reduced during the Lopingian (Late Permian) in the lead up to the end-Permian mass extinction.