【摘要】 本文首次描述了产于中国华北地台南缘,河南方城一带下寒武统辛集组中古老的双壳类化石Pojetaia runnegari Jell和Oryzoconcha prisca He et pei(gen. et sp. nov.)。它们个体微小(1—2毫米),壳体横宽,后耳微弱、韧带区发达,栉齿型铰齿,均呈内核保存。属古老的Nuculoida双壳类动物,是迄今在中国发现的最古老的双壳类动物化石。与它们共生的有软舌螺类、单板类、腹足类、海绵骨针等。更多还原

【Abstract】 The ancient Nuculoid bivalves Pojetaia runnegari Jell and Oryzoconcha prise He et Pei (gen. et sp. nov.) collected from the lower Cambrian Xinji Fromatioa in Fangcheng County, Henan Province are first time described. The bivalves are small in size(1-2mm)with well-developed ligament area, taxodont series, preserved in form of internal core.Genus Oryzoconcha (gen. nov.)Type species: Oryzoconcha prisca (gen. et sp. nov.)Diagnosis: Shell small in size (about 1 mm), equivalved, and semiequilateral. Ovat to long elliptical outline in lateral view, Umbones prosogyral, with feeble posterior auricle and well-developed ligament areas. Dentition is taxodont which consists of seven comb-like teeth and corresponding sockets in both forward and backward sides of the umbones. The pallial line is clear with pallial sinus. The external ornament of the shell surface is unknown, and the internal surface is smooth.Comparison: The new genus is similar to Fordilla, the latter may be distinuigshed by lack of a posterior auricle, less distinct dentition and undeveloped gliament areas. It is also similar to Pojetaia, but different from Pojetaia in having pallial sinus and seven comb-like teeth.Occurrence: Early Cambrian, south margin of North China Platform.更多还原