Umbria granulosa Bralower & Thierstein in Bralower et al., 1989
Bralower, T. J., Monechi, S. & Thierstein, H. R., (1989): Calcareous nannofossil zonation of the Jurassic-Cretaceous boundary interval and correlation with the geomagnetic polarity timescale. - Marine Micropaleontology. 14: 153-235.