PATTERNS AND PALEOENVIRONMENTAL IMPLICATIONS OF END-PERMIAN EXTINCTION OF RUGOSA IN SOUTH CHINA

Late Permian rugose corals are undoubtedly the last phylogenetic repre sentatives of the Rugosa. These corals are widely, though sporadically , distributed, notably in South China. The Late Permian corals of Sout h China decrease markedly in diversity and are represented by survivin g genera from the Maokouan, showing common patterns of disappearance, morphologically and phylogenetically. Colonial Wentzelellinae mostly d isappeared by the end of the Maokouan, followed by solitary Wentzelell inae and later Waagenophyllinae having simple morphologies. Non-dissep imented solitary corals and fasciculate Waagenophyllinae, though morph ologically simple, are common during the Late Permian, ranging up to t he latest Permian. Permian Rugosa apparently show two terminal pattern s, suggesting environmental differences. One pattern is terminated wit h a progressive reduction, leaving only non-dissepimented solitary cor als as survivors, and the other pattern is distinguished by the disapp earance of the platform-dwelling colonial corals at the end of the Per mian. The general trend, characterized by later disappearance of the s impler corals, reflects progressively adverse changes in the marine en vironment. The persistence and disappearance of a latest Permian Waage nophyllum fauna suggests that the regional continuation of favorable e nvironments followed by the onset of abrupt and severe, though tempora ry, environmental changes for coral growth. The causes of rugosan exti nction are not necessarily attributed to factors characteristic of the latest Permian time, and the extinction was individually stepwise, ea ch different disappearance event correlating with, and possibly caused by variable factors, such as sea-level fluctuations and volcanic acti vity. Multiple interactions of individual factors on a local and globa l scale affected each faunal component, resulting in selection of cora ls that culminates in the regional, and finally global, disappearance of Rugosa.