Tracing the origin of the planktic graptolites (Hemichordata, Pterobranchia) through the Furongian Gap (Upper Cambrian)

芙蓉纪（晚寒武世）是了解南极笔石类（笔石纲：翼鳃亚目）起源和早期演化的关键时期，也是笔石在生物地层学中应用的起点，早于寒武纪底界的笔石。不幸的是，“芙蓉间隙”，一个需要填补的化石产量低的间隔，掩盖了我们对南极笔石起源和早期演化的理解。看来，南极笔石突然起源于奥陶纪的底部，在这段时间内，对它们的早期演化变化知之甚少。S.结合对加拿大纽芬兰省绿点寒武系/奥陶系GSSP剖面和加拿大纽芬兰省大洋岔剖面早期南极笔石动物群的研究，认为中国的底栖笔石动物群具有多样性。中国）将阐明这一章在笔石的演化和他们的探索海洋环境在早古生代。在笔石中的营养性的起源和在其tubarium形成中的相关修改导致了最早的大型浮游生物在世界海洋的广阔区域中居住，在早期泥盆纪的nektic生物和浮游生物饲养者击败这些生物之前。

The Furongian (late Cambrian) time interval is the key interval to understand the origin and early evolution of planktic graptoloids (Graptolithina: Pterobranchia) and the starting point for the geological application of graptolites in biostratigraphy, long after the origination of the graptolites in the basal Cambrian. Unfortunately, the ‚Furongian Gap‘, an interval of low fossil yield that needs to be filled, masks our understanding of the origin and early evolution of planktic graptolites. It appears that planktic graptoloids suddenly originated at the base of the Ordovician and little is known about their early evolutionary changes during this time interval. The Furongian Guole lagerstätte of S. China yield a diverse benthic graptolite fauna, which, together with the investigation of early planktic graptolite faunas from the Cambrian/Ordovician GSSP section at Green Point (Newfoundland, Canada) and the Dayangcha section (N. China) will shed light on this chapter in the evolution of the graptolites and their exploration of the oceanic environment in the early Paleozoic. The origin of planktotrophy in the graptolites and the associated modifications in their tubarium formation led to the earliest macro-plankton populating the expanses of the world’s oceans, before nektic organisms and plankton feeders outcompeted these organisms in the early Devonian.