Classification: ntax_mesozoic -> Podorhabdales -> Axopodorhabdaceae -> Perissocyclus
Sister taxa: Podorhabdus, Hemipodorhabdus, Axopodorhabdus, Tetrapodorhabdus, Hexapodorhabdus, Octocyclus, Octopodorhabdus ⟩⟨ Dodekapodorhabdus, Perissocyclus, Teichorhabdus ⟩⟨ Cribrosphaerella, Ethmorhabdus, Nephrolithus, Psyktosphaera ⟩⟨ Cribrocorona

Distinguishing features: Elliptical; central area with one or two cycles of perforations and central hollow spine

Daughter taxa (time control age-window is: 0-800Ma)
Perissocyclus fenestratus
Large Perissocyclus (8-12 µm); plate with two cycles of holes around large spine
Perissocyclus liesbergensis
Small to medium (4-7 µm) mid Jurassic species. Typically with inner cycle of 4 large pores and outer cycle of 16-18 small pores - but this maybe reduced. 
Perissocyclus noeliae
Small to medium Perissocyclus (5-7 µm) with 9-18 perforations in the outer ring.
Perissocyclus plethotretus
Large (>7µm) podorhabdids with a central area grill that has an outer cycle of 12 (occasionally 10 to 14) large perforations separated by clearly birefringent struts. An additional inner cycle of perforations may be present, but these are not normally visible in the LM. The bars adjoining the central spine may be thickened to form buttresses.
Perissocyclus tayloriae
Large podorhabdid (generally >10µm) with one or two cycles of small perforations, separated by birefringent bars. These perforations are visible in XPL, but only the outer cycle is well enough defined to be easily counted and contains at least 16 perforations (16, 18, and 20 have been observed). The central spine may be supported by buttresses.
Perissocyclus sp.
Specimens not identified to species level


Citation: Perissocyclus Black, 1971
Rank: Genus
Type species: Perissocyclus noeliae Black, 1971.
Synonyms: Duplexipodorhabdus Varol & Girgis 1994 (type species P. plethotretus)

Farinacci & Howe catalog pages: Perissocyclus + *

Distinguishing features: Elliptical; central area with one or two cycles of perforations and central hollow spine

Morphology: Smaller forms (Perrisocyclus fletcheri and Perrisocyclus noeliae) are difficult to differentiate in XPL; their pores can only be counted in phase contrast and only when well-preserved. The larger forms, Perrisocyclus plethotretus and Perrisocyclus tayloriae, are distinctive and potentially useful markers species.

Search data:
TagsLITHS: placolith, ca_disjunct, grill, pores, process, CROSS-POLARS: rim-unicyclic, V-prominent, R-prominent,
MetricsLith size: 4->12µm;
Data source notes: size range of included species
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Oxfordian Stage (0% up, 163.5Ma, in Oxfordian stage). Data source: Total of range of species in this database

Plot of occurrence data:


Black, M. (1971a). Coccoliths of the Speeton Clay and Sutterby Marl. Proceedings of the Yorkshire Geological Society. 38: 381-424. gs

Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs

Varol, O. & Girgis, M. (1994). New taxa and taxonomy of some Jurassic to Cretaceous calcareous nannofossils. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 192: 221-253. gs


Perissocyclus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-4-2021

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

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