The identification of putative Lower Cambrian Radiolaria

The identity of presumed Terreneuvian (Stage 1, Fortunian) to Botoman (Series 2, Stage 3) radiolarians is discussed. The presence of radiolarians in the Lower Cambrian Hetang and Kuanchuanpu formations and the material from Jiuqunao, Hubei Province, China has to be regarded as a contamination with younger material. Oldest genuine radiolarians are recognized in Stage 5 (Series 3) of the Cambrian System, leaving the biostratigraphical and evolutionary origin of radiolarians in the early Cambrian undecided. The available fossil record indicates that early radiolarians form a spicular skeleton and are not necessarily spherical in shape. Thus, the presence of a spherical shape of small, siliceous fossils in the late Precambrian to early Palaeozoic cannot be taken as a guide for a radiolarian record.