Rich foraminiferal assemblages from the Bama Platform in South China allow clarifying the systematics, composition, and biostratigraphy of the family Janischewskinidae. The family is comprised of four genera, Janischewskina, Cribrospira, Bibradya, and Parajanischewskina. The genera Rhodesinella and Groessensella are considered to be synonyms of Cribrospira and Bibradya, respectively, and some specimens of the genus Ugurus have been included under the genus Bibradya. Seven new species are described in this study: Cribrospira evoluta, C. paradenticulata, Bibradya primitiva, B. densicamerata, B. maxima, B. subita, and Parajanischewskina nautiliformis. The biostratigraphy of the Janischewskinidae in South China resembles that in the Russian Platform, i.e., primitive Cribrospira are first recorded from the Tulian, primitive Bibradya from the Aleksinian, evolved Cribrospira (e.g., C. panderi) and large Janischewskina species from the Mikhailovian, Parajanischewskina and Bibradya maxima from the Venevian, and some species from the base of the Serpukhovian (Tarusian), such as Janischewskina delicata, J. gibshmanae, Bibradya subita, and Parajanischewskina nautiliformis. On the other hand, Janischewskina adtarusia is only documented from the late Serpukhovian strata (Zapaltyubian).

We would like to thank I.D. Somerville and two anonymous reviewers for their constructive comments. This contribution is financially supported by the National Natural Science Foundation of China (C. Liu, grant Numbers 41902102, 42172120, U1812402, and 41872117) and the Fundamental Research Funds for the Universities of Henan Province (C. Liu).

Peer reviewed