Rhomboaster svabenickae Bergen in Bralower & Bergen, 1998
Rhomboid holococcolith exhibits symmetrical extinction and features four narrow extensions from the edges of the rhomboid. Palaeorhomboaster differs from Rhomboaster by having four narrow extensions from each edge, whereas Rhomboaster has eight thin, long extensions from the corners.
Bralower, T. J. & Bergen, J. A. 1998. Cenomanian–Santonian calcareous nannofossil biostratigraphy of a transect of cores drilled across the Western Interior Seaway. In: Dean, W. E. & Arthur, M. A. (Eds.) Stratigraphy and paleoenvironments of the Cretaceous Western Interior Seaway. SEPM Concepts in Sedimentology and Paleontology. 59–77.
Schueth, J. D., Nicolas, M. & Hart, B. S. 2024. Unusual calcareous nannofossils from the Cenomanian–Turonian Western Interior Seaway of North America. Journal of Nannoplankton Research. 42(1): 85-99.