狄更逊虫类化石在我国的首次发现

THE FIRST DISCOVERY OF THE GENUS Dickinsonia (Worm) IN CHINA

狄更逊虫类化石是新元古埃迪卡拉动物群中的重要分子。本文首次报道了产于安徽寿县八公山淮南群刘老碑组（８４０Ｍａ）中的该类化石，是迄今为止世界上后生动物实体化石产出的最低层位，具有重要的理论意义和实际价值。

The genus Dicckinsonia Sprigg, 1947 is a worm (Annelida) fossil of NewProterozoic Era. It is first found from Pound Quartzite, Wilpena Group (670Ma) in Ediacaradistrict, Flinders Mountain, South Australia in 1947 accompanied with Coelenterata andArthropoda. It is an important element of Ediacara Fauna. In 1981, the genus DickinsoniaSprigg, 1947 was found in Vendian System (New Proterozoic) of Russian Platform, in WhiteSea, Northern Russian with Coelenterata, Annelida, Arthropoda and Echinoderm. This softbody metazoa fossil assemblage is called the White-Sea Fauna. In August, 1987, the same genusDickinsonia Sprigg, 1947 (Worm) was found firstly by the author in Liulaobei Formation,Huainan Group of Shouxian County, Anhui, China(see map. 1 ). It is sembiotic with macroscopicalga fossil Tawuia Hofmman, 1979.The subdivision of Huainan Group in detail is as follows (from top to bottom):Overlying strata: Fengtai Formation: pink moraine Conglomeratedolostones, calcitic dolostones intercalated with fine-grained sandsotne and shales, containingstromatolites of Mirabilla brachys, Tungussia of. inna, Eleonora of. loponica, Baicaliadubyi, B. styposa, B. of. lacera, Inzeria shouxianensis. thickness 255. 15mJiuliqiao Formation: grey, dark-grey thin silty limestones, glauconitic limestones,stromatolitic limestones, Tawuia of. dalensis of magascopic alga and Huainanellajiuliqiaoensis, Ruedemannella minuta of Annelida have been found in the thin sility limestones,containing stromatolites: maria uralica.Shouxian Formation: grey-yellow, perple-red fine-grained sandstones. thickness 44. 7mLiulaobei Formation: grey--green, yellow-green shales, fine--grained sandstones, intercalatedwith thin, grey limestones in the lower part, rich in megascopic algae with Chuaria circularis,Shouhsienia shouhsienensis, Pumilibaxa huaiheiana, Tawuia sinensis, T. dalensis; containingworm of. Dickinsonia costata Sprigg, 1947(Annelida). thickness 530. 7mBagongshan Formation: grey-white, purple-red glauconitic quartzitic sandstones, thickgrained quatzitic sandstones. thickness >22. 1mThe worm they of genus Dickinsonia Sprigg, 1947 in Liulaobei Formation, Huainan Groupis elliptical in outline, with 1. 8cm length and 1. 2cm width. It has approxinately 60 segments.There is a small, trangular pigidium at the posterior end of worm-body(see map. 3. ). In basicorganic character, it is quite similar to genus Dickinsonia Sprigg, 1947 of Ediacara Fauna in SouthAustralia, and that of White-Sea Fauna in North Rassian.The isotopic age of Liulaobei Formation, Huainan Group is 840Ma. Therefore, the firstdiscovery of this genus in china Possesses important theory significance and practical value instudying biological evolution of New Proterozoic Era and subdivision and correlation of NewProterozoic strata.Systematic Descriptionphyllam AnnelidaClass PolychaetaFamily DickinsoniidaeGenus Dickinsonia Sprigg, 1947of. Dickinsonia costata Sprigg, 1947(Plate I, figures 1--2)Diagnosis Worm-body broad, flat, elliptical in outline; with 1. 8cm length and 1. 2cmwidth; elongate, round anteriorly, tapering posteriorly, with left and right halves. It hasapproximately 60 they-segments. There is a small trangular pigidium at the Posterior end ofWorm-body.Locality and horizon: Liulaobei village, Shouxian Couty, Huainan District, Anhui Province;Liulaobei Formation, Huainan Group.