贵州遵义松林黑沙坡早寒武世牛蹄塘生物群中镇巴虫的发现

DISCOVERY OF TRILOBITE GENUS ZHENBASPIS FROM THE LOWER CAMBRIAN NIUTITANG BIOTA AT HEISHAPO, SONGLIN, ZUNYI, GUIZHON,CHINA

贵州遵义松林中南村黑沙坡下寒武统牛蹄塘生物群下部层位产有大型三叶虫 ,计有 2属 3种 ,1未定种 :ZhenbaspissubconicaS .GZhanginLuetal.,1974 ,Z .longaZhouinLeeetal.,1975 ;Zhenbaspissp .,Runna niasimilisLeeinYinetLee,,1978,确认Zhenbaspis(Zhenxiongaspis)LinetYininYinetLee ,1978,为ZhenbaspisChangetChuinLuetal.,1974的同义名。探讨Zhenbaspis的古地理分布及演化趋势。论文还描述与Zhenbaspis,Runnania共生的Tsunyidiscus及Mianxiandiscus,其中Mianxiandiscus产于下生物群即牛蹄塘组近底部 ,再次证实牛蹄塘下生物群的时代早于澄江生物群。

The Niutitang Formation of Lower Cambrian located at Heishapo of Zhongnan Village, Songlin Town, Zunyi County, Guizhou, South China yields the Niutitang Biota(Zhao Yuanlong et al., 1999; Steiner et al., 2001). It was preserved in black mudstone of the Niutitang Formation. After weathering,the exposed black mudstones become white-gray shales or mudstones. The Niutitang Biota was composed of over 23 genera belonging to 7 phyla as well as some problematic taxa. Because these fossils occur in both upper and lower parts of the Niutitang Formation, the Biota was divided to Upper and Lower Biota(Zhao Yuanlong et al., 1999; Steiner et al., 2001; Yang Xinglian et al., 2000, 2003). The main groups of fossils are sponges and arthropods(Zhao Yuanlong et al., 2002). Trilobite is rich in specimens ,but very rare in species. Recently, some genera and species have been found at the middle and lower parts of the Niutitang Formation. The occurrence of theses taxa from the Niutitang Biota is quite significant. They not only provide new information about palaeogeographical distribution of trilobite, but also enrich the composition in the Niutitang Biota.