STUDY ON THE DEVELOPMENTAL MODEL OF PHOSPHATIZED PUNCTATUS FROM THE EARLIEST CAMBRIAN OF SOUTH SHAANXI

In this paper we describe some 3D-preserved phosphatized fossils including corolliform mouthpart,5-radical cone of Punctatus and embryo fossils which were recovered from the Kuanchuanpu Member of the Dengying Formation in South Shaanxi,China. On the basis of more than 10 thousand globular fossils studied,some embryo fossils related to Punctatus are found. By systematically studying on these embryos,the authors put forward "a development model of the two-poles growth type" for Punctatus. The appearance of coelenterates marks the real beginning of meta-zoan evolution. Therefore the study of coelenterates has the prominent position in the origin and evolutionary history of organisms. The research provides some new information for the study of fossil embryology.