陕南镇巴早寒武世似软舌螺化石一新种——Torellella bisulcata sp.nov.  

EARLY CAMBRIAN HYOLITHELMINTHS——TORELLELLA BISULCATA SP.NOV. FROM ZHENBA, SOUTHERN SHAANXI

作　　者：李国祥[1] 

机构地区：[1]中国科学院南京地质古生物研究所,南京210008

出　　处：《古生物学报》2004年第4期571-578,共8页Acta Palaeontologica Sinica

基　　金：国家自然科学基金 (Nos.40 172 0 0 2 ;40 3 72 0 2 0 );国家重点基础研究发展规划项目 (G 2 0 0 0 0 7770 0 )资助课题

摘　　要：对采自陕西镇巴小洋剖面下寒武统西蒿坪段的似软舌螺类 (hyolithelminths)化石进行了研究 ,描述了一新种Torellellabisulcatasp .nov .,其主要特征为 :磷质管状壳体 ,横切面透镜状 ,壳管的两个宽面凸度不等 ,一面为弧状 ,另一面扁平 ;壳管直或微弯曲 ,在壳管的两个窄的侧面各具一纵向浅凹沟 ,壳面光滑或饰有微弱的横向纹线。简要地讨论了似软舌螺类化石的生物亲缘关系 ,认为迄今为止 ,其仍为分类位置不明的化石类别。西蒿坪段中下部产有三叶虫颊刺和颈刺 ,表明此段沉积地层属于下寒武统筇竹寺阶而非梅树村阶。The abrupt appearance of the diverse small skeletal fossils in the Early Cambrian is a major piece of evidence for the early Cambrian metazoan radiation event. In terms of skeletal composition, the early skeletal fossils could be subdivided into three groups: calcareous, phosphatic, and siliceous (Runnegar and Bengtson, 1995). The early metazoans, which utilized calcium phosphates for constructing hardparts (skeletons or sclerites), include brachiopods (Linguliformea)(Holmer, 2001), tubular fossils (hyolithelminths and Sphenothallus)(Li et al., 2004 b), bradoriids (Shu, 1990), lobopodian (e.g. Microdictyon)(Chen et al., 1995), protoconodonts and conodont-like fossils (Li et al., 2003), tommotiids (Qian and Bengtson, 1989; Bengtson et al., 1990), protoconulariids (Qian, 1999), etc. Among them, the elongated tubular fossils have been worldwide recovered from the Lower Cambrian, and are usually referred to hyolithelminths, which mainly includes two genera, Hyolithellus with circular cross-sections and Torellella with lenticular cross-sections (Fisher, 1962). Although hyolithelminths have been previously assigned to (or compared with) hyoliths (Syssoiev, 1959; Chen, 1984), annelids (serpulid polychaetes)(Qian, 1989), pogonophorans or cnidarians since these animals commonly bear or live in a tube, the biological affinities of hyolithelminths have not been resolved yet because of the simple tubular morphology and the lack of soft body preservation. The purpose of this paper is mainly to describe hyolithelminth fossils collected from the basal Cambrian Xihaoping Member in the Xiaoyang section. All specimens were obtained through acetic acid etching of carbonate samples. Based on the specimens from the Xihaoping Member at the Xiaoyang section, Torellella bisulcata sp. nov., which is mainly characterized by bearing a narrow and shallow sulcus on each narrow side, is erected. The Xiaoyang section is located at Xiaoyang, Zhenba County, Shaanxi Province, and is palaeogeographically located in the northern margin of the Ya

关 键 词：似软舌螺类 陕西 下寒武统 西蒿坪段 化石 

分 类 号：Q915[天文地球—古生物学与地层学]