Some Late Silurian characteristic radiolarians from the Yokokurayama Group in the Kurosegawa Terrane, Southwest Japan

Abstract

Late Silurian radiolarians were extracted from the Joryu Formation of the Yokokurayama Group in the Kurosegawa Terrane, Kochi Prefecture. The fauna includes the genera Pseudospongoprunum, Devoniglansus and Praespongoceolia which are regarded as the key taxa for the Upper Silurian radiolarian biostratigraphy. Five radiolarian species, including two new species, of the genera are described in this paper. The species are useful for age determination because of their characteristic shape.