中文摘要：

本文描述的三叶脊类化石于2004年采自贵州东北部江口县桃映镇翁会村埃迪卡拉系陡山沱组上部庙河生物群,共2新属2新种：中国三射盘（新属新种）Triactindiscus sinensisgen.et sp.nov.及不规则似三角形盘（新属新种）Quasitriagondiscus irregularisgen.et sp.nov.。前者为大型盘状化石,具有3个呈碳质薄膜的长三角形叶脊,自盘体中央向边缘呈三辐射伸展,没有其它生物构造;后者为小型盘状化石,3条不规则叶脊在盘体中部形成似三角形并以此不同于其它三叶脊化石。庙河生物群2个三叶脊化石属相似于俄罗斯白海生物群的Albumares,Anfesta,Tribrachidium和澳大利亚埃迪卡拉生物群中的Tribrachidium,它们细节上有差异,但均属于埃迪卡拉系中三辐射对称的三叶动物。新的发现表明三叶动物在埃迪卡拉纪广泛分布于全球各地,也显示埃迪卡拉纪生物分异度比较高,辐射、两侧及三侧对称的动物均匀代表。贵州东北部江口桃映翁会庙河生物群含有丰富的宏观藻类及动物化石,如Protoconites,Cucullus,Sinospongia,Eoandromeda octobrachiata及新发现的2属三叶脊动物化石。江口庙河生物群组成上很相似峡东庙河生物群,也都位于陡山沱组上部黑色页岩中。江口庙河生物群不仅是整个庙河生物群的重要组成部分,也是埃迪卡拉纪生物演化的重要窗口。

英文摘要：

Here we report two new genera and species of the triridged lobe fossils of the Miaohe Biota collected in 2004 from the Ediacaran Doushantuo Formation,Wenghui village,Jiangkou,northeastern Guizhou,South China.They are Triactindiscus sinensis gen.et sp.nov.and Quasitriagondiscus irregularis gen.et sp.nov.The former is a large discoidal form preserved as carbonaceous compressions,bearing three long triangles radiating from the center to the edge of the umbrella.The latter is a relatively small discoidal form with three irregular lobes forming a closed triangle around the center of the umbrella.The gross morphologies of the two new genera resemble Albumares,Anfesta and Tribrachidium from the White Sea,Russia,and Tribrachidium from the Ediacara Hills,Australia.These forms represent trilobozoan animals with tri-radial symmetry in the Ediacaran System.However,upon close examination,there are obvious morphologic differences among these forms.Our new findings indicate that trilobozoans extended their global geographic range quickly in a relatively short period of time and show high diversity in the Ediacaran System.The Miaohe Biota from Wenghui village,Jiangkou northeastern Guizhou is dominated by a megascopic algal fossil assemblage associated with a few types of possible metazoans,such as Cucullus,Protoconites,Sinospongia,Eoandromeda octobrachiata and the two new genera described herein.The Miaohe Biota from Jiangkou is very similar to the Miaohe Biota from the Zigui area,Hubei Province,in both taxonomic composition and taphonomic mode.Both assemblages occur in black shales of the upper Doushantuo Formation,but the Jiangkou assemblage contains more diverse animal forms;thus,it reveals new aspects of the Miaohe Biota,providing an important window of early metazoan evolution in Ediacaran time.