Fusuline faunas including 29 species belonging to 19 genera/subgenera are described from the Thitsipin Formation in eight sections/localities on the Shan Plateau in eastern Myanmar. These fusulines broadly indicate a Midian (middle Permian, Guadalupian) age. The lower diversity and the presence of some genera, such as Monodiexodina and Eopolydiexodina, suggest that the Sibumasu Block belonged to the palaeobiogeographic Cimmerian Province during the Midian. Furthermore, quantitative cluster analysis of middle Permian fusulines from the Shan Plateau and adjacent Cimmerian blocks suggests close faunal affinities between the Sibumasu Block and the Baoshan Block in western Yunnan. More importantly, the widespread occurrence of fusulines Eopolydiexodina afghanensis and Jinzhangia shengi on the Shan Plateau is similar to that of contemporaneous fusuline faunas from the Baoshan Block and the South Qiangtang Block but different to that of the Tengchong and Lhasa Blocks, which are dominated by the characteristic Nankinella–Chusenella assemblage. This faunal discrepancy provides strong evidence that the Bangong–Nujiang suture passes through the Gaoligong Orogen in western Yunnan rather than through the Myitkyina ophiolites in northern Myanmar. Additionally, palaeobiogeographical analysis of these fusuline faunas from the Lhasa, Tengchong, South Qiangtang, Baoshan and Sibumasu Blocks implies that the Bangong–Nujiang Ocean might have been present before the Midian.

中文翻译：

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缅甸of邦Thipsipin组的中二叠纪fusulines及其古生物地理和古地理意义

在缅甸东部山地高原的八个断面/地方的Thitsipin组中描述了包括19个属/亚属的29个物种在内的Fusuline动物区系。这些fusuline大致表明了一个中纪（中二叠纪，瓜达卢普纪）的年龄。较低的多样性和某些属如Monodiexodina和Eopolydiexodina的存在，表明Sibumasu块在Midian时期属于古生物地理的Cimmerian省。此外，对来自陕高原和邻近的Cimmerian区块的中二叠纪fusuline进行的定量聚类分析表明，滇西的Sibumasu区块与Baoshan区块之间具有紧密的动物亲和力。更重要的是，fusulines Eopolydiexodina afghanensis的广泛发生高原上的金丝雀和金樟子生动物与宝山地块和南Qian塘地块的同时伏龙类动物群相似，但与腾冲和拉萨地块不同，它们以南金氏菌-丘氏菌组合为主导。这种动物上的差异提供了有力的证据，证明班公一怒江缝合线穿过云南西部的高黎贡造山带，而不是穿过缅甸北部的密支蛇绿岩。此外，对这些来自拉萨，腾冲，南Qian塘，宝山和西布玛苏地块的梭链动物的古生物地理分析表明，班贡—怒江洋可能早于米甸就已存在。