Reticulofenestra sessilis

Classification: Coccolithophores -> Isochrysidales -> Noelaerhabdaceae -> Reticulofenestra -> R. parvula group -> Reticulofenestra sessilis
Sister taxa: R. maceria, R. parvula, R. sessilis,


Citation: Reticulofenestra sessilis (Lohmann 1912) Jordan & Young, 1990
Rank: Species
Basionym: Pontosphaera sessilis Lohmann 1912
Notes & discussion: Unambiguous Reticulofenestra disappears in the Early Quaternary but there are small reticulofenestrids without bridges though the Quaternary and a couple of extant species, including R. sessilis (see Young 2005), these are conventionally referred to Reticulofenestra but may prove to have descended from Gephyrocapsa by loss of the bridge.

Distinguishing features: Closed central area. Rather heavily calcified giving irregular form, strongly crenulate margin.

Farinacci & Howe catalog pages: Pontosphaera sessilis * , Cyclolithella taiwanea *

Size: Coccospheres 6-10 µm; liths 2.5-4 µm.

Ecology & Biogeography: Occurs almost exclusively in symbiotic(?) associations with a centric diatom of the genus Thalassiosira. Deep photic.

Search data:
TagsLITHS: placolith, elliptical, RIM: inner-tube-broad, CA: Placoliths: closed,
CSPH: spherical, monomorphic, V-UNITS: none, R-UNITS: all, c-str, distal shield, prox shield, tube, DETAILS: isogyres kinked, isogyres oblique, rim-unicyclic,
MetricsLith size: 2.5->4µm; Coccosphere size: 6->10µm; Liths per sphere: 10->30
Sources: lith & csph size from illustrated specimens; lith numbers from Yang & Wei 2003, range of estimates
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): Extant Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within Quaternary Period (0.00-2.59Ma, base in Gelasian stage). Data source: [JRY rough estimate]

Plot of occurrence data:

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: R. parvula group


    Chen, M. -P. (1980). Modern and redeposited coccolithophores for the indication of sediment dispersal pattern around Taiwan offshore region. Acta Oceanographica Taiwanica. 11: 129-156. gs

    Lohmann, H. (1912). Untersuchungen über das Pflanzen- und Tierleben der Hochsee, zugleich ein Bericht über die biologischen Arbeiten auf der Fahrt der "Deutschland" von Bremerhaven nach Buenos-Aires in der Zeit vom 7. Mai bis 7. September 1911. Veröffentlichungen des Instituts für Meereskunde an der Universität Berlin. Neue Folge. A. Geographisch-naturwissenschaftliche Reihe. 1: 1-92. gs

    Young, J. R., Geisen, M., Cros, L., Kleijne, A., Probert, I. & Ostergaard, J. B. (2003). A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research, Special Issue. 1: 1-132. gs


    Reticulofenestra sessilis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-10-2019

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    Short stable page link: Go to to create a permanent copy of this page - citation notes

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