陕西南郑中奥陶世三叶虫拾遗  

AN ORDOVICIAN (EARLY LLANVIRN) TRILOBITE FAUNULE FROM NANZHENG, SOUTHERN SHAANXI

作　　者：陈润业[1] 周志毅[2] 

机构地区：[1]西北大学地质系,西安710069 [2]中国科学院南京地质古生物研究所,南京210008

出　　处：《古生物学报》2002年第2期219-231,229-231,共13页Acta Palaeontologica Sinica

基　　金：国家自然科学基金 (No .49772 0 87);国家重点基础研究发展规划项目 (G 2 0 0 0 0 7770 0 )

摘　　要：描述陕南南郑梁山中奥陶世Llanvirn早期 7种三叶虫 ,包括两个新种Bathycheilussinensissp .nov .和Pseudocalymenesculptasp .nov .,其中Bathycheilus一属在我国系首次发现。三叶虫组成和埋葬相特征表明这一动物群的底栖分子应生活于水体安静 ,深度大于风暴浪基面的灰泥质海底环境。这些底栖三叶虫属于环冈瓦纳动物群的一个组成部分 ,但显示了与北欧动物群的一定联系。Only seven trilobite species were previously described by Lu (1975) from the basal part of the “ Yangtzeella poloi beds” at Zhajiagou, about 300 m southwest of the Xialiangshan village, Nanzheng County,southern Shaanxi (Lu,1975, text fig.10). All are from an 8 m marlite (Bed 7, Lu, 1975,p. 49, text fig.11), which is rich in biocalcilutite nodules. They constitute a nileid dominate assemblage, including Nileus armadilloformis Lu, N. walcotti Endo(= N.liangshanensis Lu, see Zhou et al., 1998), Symphysurus carinatus Lu, S. subquadratus Lu, Dikelokephalina gibbosa Lu, Neseuretus concavus tenellus Lu and Ogmasaphus hannanicus (Lu) (= Pseudasaphus hannanicus Lu, see Zhou et al., 1998). New material was collected along the Zhajiagou section from a silty marlite of 2 m thick. The horizon, according to Lu (1975,p.49), lies at the base of Bed 8, which is altogether 12 m in thickness, representing the lower part of the “Yangtzeella poloi beds”. After critical identification, the collection contains following 13 trilobite species: Carolinites sp., Bathycheilus sinensis sp. nov., Hemisphaerocoryphe elliptica (Lu) (= Ellipsocoryphe elliptica Lu, see Zhou et al ., 1998), Prionocheilus sp., Ovalocephalus cf. intermedius (Lu and Zhou), Sinocybele cf. baoshanensis Sheng, Pseudocalymene sculpta sp. nov., Lonchodomas sp., Liomegalaspides usuii (Yabe), Yanhaoia huayinshaensis (Lu)(= Pterygometopus huayinshanensis Lu, see Zhou et al., 1998), Ogmasaphus hannanicus (Lu) and Mioptychpyge zhenbaensis (Zhou)(= Basiliella zhenbaensis Zhou, see Zhou et al., 1998).The faunule is dominated by the bathycheilid Bathycheilus, which makes up 25% of the total collected specimens. The encrinurid Sinocybele (20%) and leiostegiid Pseudocalymene (14%) rank respectively second and third. Trilobites are all randomly distrbuted and poorly sorted with no distinct reworking. Some of them are disarticulated, but about 4

关 键 词：三叶虫 中奥陶世 南郑 陕西 

分 类 号：Q915.8[天文地球—古生物学与地层学]