河南灵宝朱阳下寒武统辛集组软体动物群的发现

DISCOVERY OF THE MOLLUSCAN FAUNA FROM THE LOWER CAMBRIAN XINJI FORMATION OF ZHUYANG, LINGBAO OF HENAN

河南灵宝朱阳地区下寒武统辛集组中新发现的小壳动物化石包括软体动物群的软舌螺、单板类、双壳类和腹足类以及海绵骨针和齿形类。该动物群可与安徽淮南雨台山组、河南确山、叶县、宝丰及陕西洛南辛集组动物群对比,时代属早寒武世中期,与澳大利亚新南威尔士早寒武世中期软体动物群属同一生物地理区。软体动物有可能在中国云南开始出现,并迅速迁移至扬子浅海各地,后经某种渠道迁移到华北地台南缘,演化成新的动物群。

The small shelly fossils found recently from the Lower Cambrian Xinji Formation of the Zhuyang area, Lingbao City of Henan Province, comprises hyoliths and molluscs including monoplachophorans, bivalves and gastropods, as well as sponge-spicules and conodontmorpha. The molluscan fauna can be correlated with those of the Yutaishan Formation in Huainan of Anhui and those of the Xinji Formation in Queshan, Yexian and Baofeng Counties of Henan, and those of the Xinji Formation in Luonan County of Shaanxi. The geological age of the fauna is determinated to be the middle Early Cambrian. The fauna of this area may belong to same biogeographic province as the middle and late Early Cambrian molluscan faunas of New South Wales, Australia because there are many same genera and species between the two areas. The molluscan fauna might be originated in Yunnan, China, then dispersed rapidly to the other area of the Yangtze shallow sea, at last migrated to the southern margin of the North China Platform through certain channel and evolved into a new fauna.