Calcified cyanobacteria are of considerable research value for reconstructing the ecology of Paleozoic and Mesozoic benthic communities on carbonate platforms due to their ability to produce oxygen and fix nitrogen and CO2. The diversity and abundance of calcified cyanobacteria was initially suggested to have declined in the Middle and Late Ordovician, although more recent work suggests that complex and diverse assemblages persisted throughout the Ordovician. Here, calcified cyanobacteria and associated microfossil flora from the Middle and Late Ordovician of the Ordos Basin, North China Block, are systematically described for the first time based on 1330 thin sections from seven outcrop profiles and four drill cores. In total, there are 18 species belonging to 16 genera, including a new species,Proaulopora ordosian. sp.Girvanella,Subtifloria,Acuasiphonoria,Xianella, and Oscillatoriaceae gen. indet. are assigned to Osillatoriales of cyanobacteria;Ortonella,Hedstroemia,Cayeuxia,Zonotrichites,Proaulopora, andPhacelophytonare assigned to Nostocales of cyanobacteria; andGarwoodia,Renalcis,Izhella,Rothpletzella, andWetheredellaare assigned to calcified Microproblematica. A literature survey of Ordovician microfloral assemblages shows that cyanobacteria and associated microfossils occur in reef, open platform, lagoon, and tidal facies. Most genera occur on at least two independent blocks, and many have a cosmopolitan distribution in similar sedimentary facies. Our research suggests that calcified cyanobacteria and associated microfossils formed complex ecosystems and played greater ecological roles on carbonate platforms during the late Middle and Late Ordovician than was previously thought.UUID:http://zoobank.org/1812ccf8-136c-4cff-92ba-faeaf06523ef

中文翻译：

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华北鄂尔多斯盆地中晚奥陶世钙化蓝藻及相关微化石的多样性和系统性

钙化蓝藻具有产氧、固氮和CO的能力，对重建碳酸盐台地古生代和中生代底栖生物群落生态具有重要的研究价值2. 最初认为钙化蓝藻的多样性和丰度在中奥陶世和晚奥陶世有所下降，尽管最近的研究表明复杂多样的组合在整个奥陶世持续存在。在这里，基于七个露头剖面和四个钻芯的1330个薄片，首次系统描述了华北地块鄂尔多斯盆地中晚奥陶世钙化蓝藻及其相关微化石群落。总共有16个属18个种，包括一个新种，原毛霉n. sp。格瓦内拉,小花属,听音,夏内拉, 和 Oscillatoriaceae 根。索引。被分配给蓝藻的 Osillatoriales；奥托内拉,紫杉,卡约夏,Zonotrichites,原毛孔虫， 和褐藻属被分配到蓝藻的念珠菌目；和加木属,肾素,伊热拉,罗氏菌属， 和韦瑟雷德拉被分配给钙化的 Microproblematica。一项对奥陶纪微生物群落组合的文献调查表明，蓝藻和相关的微化石出现在珊瑚礁、开放平台、泻湖和潮汐相中。大多数属至少出现在两个独立的地块上，并且许多属在相似的沉积相中具有世界性分布。我们的研究表明，在中奥陶世晚期和奥陶世晚期，钙化的蓝藻和相关的微化石形成了复杂的生态系统，并在碳酸盐平台上发挥了比以前认为的更大的生态作用。UUID：http://zoobank.org/1812ccf8-136c-4cff-92ba-faeaf06523ef