摘要
扼要介绍陕西宁强地区震旦系灯影组高家山段种类繁多 ,保存精美 ,实属国内外所罕见的管壳化石类群 ,该类化石暂按管壳形态结构分为单层管壳类和多层管壳类。前者以Chenella为代表 ,后者又分具套管式结构类以Sinotubulites为代表和具叠锥套合式结构类以cloudinids为代表。类似管壳化石在世界已有 11个产地 ,层位稳定 ,对于末元古纪的时代划分和揭示早期动物的演化方向具有重要意义 ;同时在一定程度上说明前寒武纪与寒武纪生物演化的连续性 ,寒武纪之初生物“大爆发”并非“突然”。
The advent of organisms with skeletons was long considered to have occurred in the lowermost Cambrian. Germs(1992)described the first Precambrian skeletal fossil Cloudina from the Nama Group of Namibia. Since then, similar fossil assemblages have been found in Upper Vendian sequences of Argentina (Yochelson and Herrea, 1974),China(Chen and Wang,1977; Chen et al .,1981; Zhang, 1986; Zhang et al ., 1992), Antarctica(Yochelson and Stump,1977), Brazil (Hahn and Pflug,1985; Zaine and Fairchild, 1987), Mexico (McMenamin, 1985), North America (Taylor,1986; Signor et al ., 1987), Spain(Palacios, 1989), Middle East(Conway Morris et al .,1990) and Uruguay(Gaucher and Sprechermann, 1999), and as important as the Ediacaran Fauna, they have potential significance in the subdivision of the terminal Proterozoic and in the study of early evolution of animals, and to some extent in disclosing the mystery of the “Starting Point” and primary stage of the earliest bioskeletonization. Highly variable and delicately preserved, the tubular shell fossil assemblage in Gaojiashan section of Sinian Dengying Formation in Ningqiang, Shaanxi can be subdivided into two types in morphology, namely, single layered tubular shell, represented by Chenella, and multi layered fossils including column in column structures and cone in cone structures, represented by Sinotubulites and cloudinids respectively. Chenella, straight or slightly curved cylindrical structure, generally smooth on the external wall, and rarely bear longitudinal sculpture. 1—4 mm in diameter, and 9—25 mm in preserved length. Four species have been established mainly based on the sculptures on their outer wall,i.e Chenella laevis Zhang et al., 1992, C. canaliculata Zhang et al .,1992, C. costata Zhang et al .,1992 and C. regularis sp.nov. Zhang et Hua. Sinotubulites, nearly cylindrical structure, with thick wall and prominent irregular surface ornaments including longitudinal sculptures
出处
《古生物学报》
CAS
CSCD
北大核心
2000年第3期326-333,共8页
Acta Palaeontologica Sinica
基金
国家自然科学基金!(No .49772 0 81)
孙卫国优秀中青年人才专项基金资助项目
