地中海果蝇HIRNANTIAN (LATEST ORDOVICIAN) GRAPTOLITES FROM THE UPPER YANGTZE REGION, CHINA
期刊名称： Palaeontology
加热搅拌反应釜
作者： CHEN XU,FAN JUN‐XUAN,M. J. MELCHIN,C. E. MITCHELL
发明网
期号： 第2期
关键词： Hirnantian;graptolites;extinction;astogenetic pattern;Yangtze region
摘要：The Upper Yangtze region yields a Hirnantian (latest Ordovician)
覆膜胶
graptolite fauna that includes 41 species assigned to 13 genera. This fauna is particularly important for understanding the Late Ordovician mass extinction event because it is the most diverse known from this interval. In addition, it records the survival, well into the Hirnantian, of many taxa of the Dicranogra
ptidae-Diplograptidae-Orthograptidae (DDO) fauna, which was previously regarded as having gone extinct at the beginning of the Hirnantian. Taxa exhibiting six different astogenetic patterns, including taxa with reclined stipes, scandent, biserial, full-periderm and 'archiretiolitid' rhabdosome forms occur in the lower Normalograptus extraordinarius-N. ojsuensis Biozone. In contrast, in the upper N. persculptus Biozone only four genera remain, all but one
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