Rotalidium Asano 1936

Rotalidium es un género de foraminífero bentónico de la subfamilia Ammoniinae, de la familia Rotaliidae, de la superfamilia Rotalioidea, del suborden Rotaliina​ y del orden Rotaliida.​ Su especie tipo es Rotalidium pacificum. Su rango cronoestratigráfico abarca desde el Mioceno superior hasta la Actualidad.

Test lenticular, trochospiral, about four slowly enlarging whorls, the final one with ten to fifteen chambers, sutures limbate, elevated on the spiral side, incised on the umbilical side and leaving wide interlocular spaces with feathered margins, narrow umbilicus with an umbilical plug containing a single vertical cavity in small individuals and numerous irregular vertical canals in larger specimens, umbilical space of preceding whorl covered by umbilical extensions from the chambers to become a broad spiral canal, intraseptal canal system consists of a single broad radial canal in each septum that opens at the peripheral end of the suture on the umbilical side; wall calcareous, finely perforate, spiral side with elevated septal and spiral sutures and ridgelike thickenings near the apex, umbilical side with smooth surface except for the pustulose, ridgelike sutural margins and central umbilical pillars; aperture an interiomarginal arch between the umbilical margin and periphery. U. Miocene to Holocene; Japan; Hong Kong; Borneo; Indian Ocean. (Loeblich & Tappan, 1987, Foraminiferal Genera and Their Classification)