Nannotax Enabling nannofossil research

Description: Coccoliths >5μm (cf. e.g.: Backman, 1980; Young, 1991). Often dominates Middle Miocene - Early Pliocene assemblages.

Remarks: For biostratigraphy it is better to separate the >7μm specimens (e.g.: Rio et al., 1990; Raffi et al., 1995); i.e. a definition of >7µm is preferable for unambiguous identification of both the NN15/16 boundary (last occurrence of R. pseudoumiblicus) and the NN10A/B boundary (start of small Reticulofenestra interval/R.pseudoumbilicus paracme) .

Range: NN4 to 15.

Variants:
R. ampliumbilicus Theodoridis, 1984 - forms with very wide central-area, possibly an early growth phase.

R. antarctica (Haq, 1976) Driever, 1988 [Dictyococcites]- closed central-area

R. tenuistriata (Kamptner, 1963) Martini, 1979 [Coccolithus] - sensu Varol, 1989 = 5-7μm R. pseudoumbilicus.