Classification: Coccolithophores -> Syracosphaerales -> Rhabdosphaeraceae
Sister taxa: Calciosoleniaceae, Rhabdosphaeraceae, Syracosphaeraceae,

Distinguishing features: BCs planoliths with radial lath cycle and highly-variable axial structures. Often polymorphic and/or varimorphic

Daughter taxa: (blue => in age window 0-800Ma) Granddaughter taxa
Body coccoliths with well-developed radial lath cycle, low mound in centre; coccospheres polymorphic, usually some coccoliths with well-developed spines

Body coccoliths with well-developed radial lath cycle; domal or double-lipped protrusion; coccosphere dimorphic, CFCs larger and taller

Coccoliths process-bearing with complex base including outer rim, radial lath and lamellar cycles

Body coccoliths with well-developed radial lath cycle, protrusion in centre; coccospheres varimorphic higher protrusions on circum-flagellar coccoliths

Body coccoliths with well-developed radial lath cycle; trumpet-like process; coccospheres monomorphic

Coccoliths without radial lath cycle; coccospheres monomorphic, all spine-bearing

Large, narrow, spine-like nannofossil that tapers towards both ends and has a narrow central canal.

Coccoliths without radial lath cycle; coccospheres dimorphic, only some spine-bearing

Coccoliths without radial lath cycle; coccosphere dome-shaped, polymorphic


Citation: Rhabdosphaeraceae Haeckel, 1894
Rank: Family

Farinacci & Howe catalog pages: Rhabdosphaeraceae [no catalog entry yet]

Distinguishing features: BCs planoliths with radial lath cycle and highly-variable axial structures. Often polymorphic and/or varimorphic

Morphology remarks: Coccospheres: Motile or non-motile, typically with spine-bearing and non-spine-bearing coccoliths with similar shields, but polymorphic, varimorphic and monomorphic genera also occur. The spine-bearing coccoliths may be confined to the poles or distributed around the coccosphere, greatly increasing its outer diameter.
Coccoliths: Typically disc-shaped (planoliths) and formed of three components.
  1. Rim: narrow; slightly elevated; formed of two cycles of elements. A. Upper/outer rim cycle of simple non-imbricate elements (Kleijne 1992), these are V-units (our LM obs.). B. Lower/inner rim cycle showing strong obliquity. Crystallographic orientation uncertain.
  2. Radial cycle - joins rim to central lamellar cycle; radial laths, of equal number to rim units; slits often present between the laths (absent in Rhabdosphaera and Saturnulus).
  3. Lamellar cycle(s) - lamellar elements showing clockwise imbrication, often multiple cycles with inner cycles more elongate, inclined and in helical arrangement forming spine or protrusion. May end in a "cuneate cycle" of a few well-formed elements.

Biology & life-cycles: A couple of species are known to form HOL-HET combinations, only Algirosphaera robusta has been maintained in culture.

Search data:
TagsLITHS: planolith, RIM: rim-narrow, CA: grill, DETAILS: ca_disjunct,
MetricsLith size: 1->30µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: Most extant Rhabdosphaeraceae are very small and, apart from R. clavigera, are rarely recorded in the fossil record. There is, however, a diverse and abundant group of larger Rhabdosphaeraceae in the Eocene (see also Perch-Nielsen 1985b; Varol 1989; Shafik 1989; Aubry 1999, Bown 2005).
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): at base of Selandian Stage (4% up, 61.5Ma, in Selandian stage). Data source: Total of range of species in this database

Plot of occurrence data:


Aubry, M.-P., (1999). Handbook of Cenozoic calcareous nannoplankton. Book 5: Heliolithae (Zygoliths and Rhabdoliths). Micropaleontology Press, American Museum of Natural History, New York, 368 pp.GS

Bown, P.R., (2005). Palaeogene calcareous nannofossils from the Kilwa and Lindi areas of coastal Tanzania (Tanzania Drilling Project 2003-4). Journal of Nannoplankton Research, 27(1): 21-95.GS

Bown, P.R., (2010). Calcareous nannofossils from the Paleocene/Eocene Thermal Maximum interval of southern Tanzania (TDP Site 14). Journal of Nannoplankton Research, 31: 11-38.GS

Haeckel, E., (1894). Systematische Phylogenie der Protisten und Pflanzen. Reimer, Berlin.GS

Kleijne, A., (1992). Extant Rhabdosphaeraceae (coccolithophorids, class Prymnesiophyceae) from the Indian Ocean, Red Sea, Mediterranean Sea and North Atlantic Ocean. Scripta Geologica, 100: 1-63.GS

Perch-Nielsen, K., (1985). Cenozoic calcareous nannofossils. In: Bolli, H.M., Saunders, J.B. and Perch-Nielsen, K. (Editors), Plankton Stratigraphy. Cambridge University Press, Cambridge, pp. 427-555.GS

Probert, I.; Fresnel, J.; Billard, C.; Geisen, M. & Young, J.R., (2007). Light and electron microscope observations of Algirosphaera robusta (Pymnesiophyceae). Journal of Phycology, 43: 319-332.GS

Shafik, S., (1989). Some new calcareous nannofossils from Upper Eocene and Lower Oligocene sediments in the Otway Basin, southeastern Australia. Alcheringia, 13: 69-83.GS

Varol, O., (1989). Eocene calcareous nannofossils from Sile (northwest Turkey). Revista Española de Micropaleontología, 21: 273-320.GS


Rhabdosphaeraceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 25-4-2019

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=1201 Go to Archive.is to create a permanent copy of this page - citation notes

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