• 责任者：Liu Yunhuan (School of Earth Sciences and Resources ; Chang’an University ; Xi’an 710054 ; China) ; Shao Tiequan
• 刊名：Journal of Earth Sciences and Environment
• 出版年：2013
• 卷期：35(3)
• 关键词：生物群落 ; biocenoses ; 陕西 ; Shaanxi Province
• 页码：p.39-43
• 图表：3 illus., 20 refs.
• 分类号：1100
• issnNo：ISSN1672-6561
• isbnNo：CN61-1423/P

     The Meishucun stage is a crucial interval in Cambrian explosion, when an evolutionary radiation and innovation of eumetazoa bauplan took place. Recently, a large number of small shelly fossils （SSF） from Kuanchuanpu Formation of Lower Cambrian were discovered in Zhangjiagou of Xixiang county, southern Shaanxi province. A lot of cnidarias in different stages including square pyramid-sharp shell Quadrapyrgites and other small shelly fossils with different morphologies were developed, so a new boita ＂Xixiang Boita＂ was established. The growth model for square pyramid-sharp shell was discussed, and individual evolutionary sequence was improved. The results show that the appearance of diploblastic cnidaria marks the beginning of eumetazoa evolutionary, and it is important for the origin and evolutionary of organisms. Quadrapyrgites fossil and other small shelly fossils in Xixiang Boita of southern Shaanxi province provide new evidence for studying the origin, evolution and bauplan of eumetazoa.