山东寒武系馒头组等刺虫化石的发现

NEW ISOXYS(ARTHROPODA) FROM THE CAMBRIAN MANTOU FORMATION,SHANDONG PROVINCE

等刺虫(Isoxys)是寒武纪海洋中一类分布广泛的双瓣壳节肢动物,在北美、欧洲、澳大利亚、西伯利亚及中国均有发现,但延续时间并不长,目前已经描述了16个已命名的种以及一些未定种化石。等刺虫在我国扬子地台云南滇东地区、贵州凯里、湖北长阳等地寒武系第二、第三统均有发现。文中报道的等刺虫发现于山东省临沂市刘庄镇馒头组顶部,没有保存软体部分,被命名为一个新种Isoxys shandongensis Wang and Huang sp.nov.。同时,对美国寒武系Spence页岩保存的未定名等刺虫软体部分特征进行修订,并进行形态比较。等刺虫的新发现对探讨这类常见的寒武纪节肢动物的演化、分布和多样性均有一定意义。

The bivalved arthropod Isoxys had a cosmopolitan distribution in Cambrian seas.They are reported from the North America,Spain,Siberia,Australia and Southwest China.All material from China occurrs in a wide area of the Yangtze Platform,including in the Chengjiang and Guanshan faunas from Yunnan Province,the Kaili fauna from Guizhou Province,and the Changyang district from Huibei Province.Isoxys shandongensis Wang and Huang sp.nov.from the Mantou Formation （Zhangxia Stage） near Sikou Village,Liuzhuang Township,Feixian County,Linyi City of Shandong Province,eastern China,is described herein.The fossils are preserved in a green-gray shale from which other soft-bodied animals had also been found.