Polysphaeridium cephalum Kar, 1979
Originally Polysphaeridium, subsequently Sumatradinium, thirdly Batiacasphaera?.
Tax. jr. synonym of Operculodinium placitum Drugg and Loeblich Jr., 1967, according to Jain and Garg, 1991.
Holotype: Kar, 1979, pl.4, figs.66a-b
Age: Oligocene