陕南张家沟剖面寒武纪早期微体化石Hexaconularia sichuanensis的新材料*

陕南西乡张家沟剖面的寒武系下部岩层中发现了大量原始锥石类,根据整体形态特征和原始锥石类化石分类方案将其归属到六方锥石属Hexaconularia。前人对于六方锥石分类方案众多,本文对其进行重新厘定。本文报道的六方锥石新材料在中央锥面上具有两条不连续的角沟,这不仅丰富了种内特征,而且为六方锥石的壳体演化趋势提供了依据。前人发现的该类化石与本文描记的化石类型相同,产地不同,因而具有地层对比意义。

NEW MATERIALS OF EARLY CAMBRIAN MICROFOSSILS HEXACONULARIA SICHUANENSISFROM ZHANGJIAGOU SECTION IN SOUTHERN SHAANXI

A large number of protoconulariid fossils were found in the lower Cambrian strata of Zhangjiagou Section in Xixiang,South Shaanxi.According to its overall morphological and the classification of protoconulariid fossils which belong to Hexaconularia.Predecessors made many classifications about Hexaconularia, but we reclassified it.There are two shallow and discontinuous corner grooves at the central face.This not only enriches the intraspecific characteristics,but also provides the basis for the evolution trend of shell.The same type as fossils described in this article have been reported by predecessors but from different places,thus it has important research meaning to the stratigraphic comparison.