Revision of the Early Cretaceous Radiolarian Species Williriedellum salymicum Kozlova

Abstract

Based on the revision of the radiolarian species Williriedellum salymicum Kozlova, 1983 (Nassellaria, fam. Williriedellidae Dumitrica, 1970), new description of this species was made. Since the holotype of this species is petrographic thin section with incomplete set of characters, we suggest to address the International Commission on Zoological Nomenclature a proposal to distinguish the neotype. The distribution interval of Williriedellum salymicum Kozlova, 1983 is limited by the Berriasian deposits of the North Russia. The SEM and X-ray microtomographic 3D-images of this species from Zone Parvicingula khabakovi–Williriedellum salymicum of the Bazhenov Formation from the Gubkinskaya 651 and Aprelskaya 11 boreholes, correspondingly, are given in this work for the first time.