Guiuva sashidai n. gen. n. sp., a probable colonial radiolaria from the Lopingian (Upper Permian) in South China

Guiuva sashidai Ito and Feng n. gen. n. sp., characterized by bunchy aggregations comprising combined small spherical shells with porous surfaces, was discovered from the Lopingian (Upper Permian) of the Yutouling section in the Xiaodong area, Guangxi Zhuang Autonomous Region, South China. The morphological similarities with recent radiolarians and formation of the aggregations imply that this species is a colonial radiolaria. This species is ca. 200 myr older than previously-reported occurrences of colonial radiolarians from the Eocene. It is believed that colonial radiolarians live exclusively in association with symbiotic algae, based on previous observations of the extant forms. Therefore, it is plausible to suggest that G. sashidai had symbionts, which would indicate that the origin of symbiont-bearing radiolarians dates back at least to the Permian. On this basis, we suggest that this is the oldest known example of symbiont-bearing radiolarians.