Biantholithus sparsus Bramlette & Martini, 1964
The weakly birefringent placoliths have two shields about equal diameter. Six to twelve segments in each shield. The segments may or may not join all their length. The tube cycle is visible only proximally
Biantholithus sparsus is possibly the ancestor of Discoaster Tan Sin Hok (1927) but differ from it by having double-cycle shields with weak birefringent.
Bramlette, M. N. & Martini, E., (1964): The great change in calcareous nannoplankton fossils between the Maastrichtian and Danian. - Micropaleontology. 10(2): 291-322.
Tan Sin Hok, (1927): Discoasteridae incertae sedis. - Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen. Sect Sci, 30: 411-419.