贵州剑河八郎寒武系“清虚洞组”单板类化石Oelandiella

OELANDIELLAFROM THE CAMBRIAN “ TSINGHSUTUNG FORMATION ” OF JIANHE COUNTY,G UIZHOU

贵州剑河八郎松山寒武系都匀阶"清虚洞组"上部三叶虫Redlichia(R.)guizhouensis-Redlichia(R.)nobilis顶峰带产包括软躯体化石的多门类化石组合,文中描述其中的单板类化石小厄兰岛螺属(Oelandiella Vos-tokova,1962),含2相似种和1未定种:Oelandiella cf.accordinonata(Runnegar and Jell,1976)emended,Oe-landiellacf.taijiangensis(Mao et al.,1993)emended和Oelandiellasp.。讨论并确认Oelandiella和Latouchel-la的主要区别是前者的同缘褶横过背脊,后者的肋突分布于壳两侧,背脊光滑无饰,从而指出国内过去归入Latouchella属具横过背脊同缘褶的种不符合Latouchella的属征,应予甄别。新分类研究表明,毛家仁等(1993)在同一剖面"清虚洞组"顶部所鉴定的Helcionella terraustralis Runnegar and Jell,1976应定为Oelandiellacf.ac-cordinonata(Runnegar and Jell,1976)emended。具细密环纹锥管构造Oelandiella在剑河八郎"清虚洞组"的发现,为寒武纪单板类的分类学、形态学及其演化等研究提供了很好的化石材料。

Abundant specimens of the univalved helcionelloid mollusc Oelandiella have been found in mudstones and fine-grained carbonates of the Songshan section in the upper part of the ＂Tsinghsutung Formation＂, within the Qiandongian series （Cambrian, Duyunian stage） of Jianhe County,Guizhou. This formation belongs biostratigraphically to the Redlichia （R. ） guizhouensis-Redlichia（R. ）nobilis acme zone in the Songshan Section and is located near to the Wuliu-Zengjiaya Section and is located near to the Wuliu-Zengjiaya Section at Balang, which is also in Jianhe County. Two confirmed species Oelandiella c{. accordinonata （Runnegar and Jell, 1976） emended here,