Nannotax3 - ntax_main - Perissocyclus

Nannotax3 - ntax_main - Perissocyclus Nannotax3 - ntax_main - Perissocyclus

Perissocyclus

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

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

Taxonomy:

Citation: Perissocyclus Black, 1971

Taxonomic rank: genus

Type species: Perissocyclus noeliae Black, 1971.

Synonyms: Duplexipodorhabdus Varol & Girgis 1994 (type species P. plethotretus)

Distinguishing features:
Parent taxon (Axopodorhabdaceae): Regular placoliths; central-area, with cross-bars or perforated plate; often with tall, hollow spines.
Distal shield elements non-imbricate V-units; proximal shield and inner cycle formed from R-units. Rim often appears beaded in LM
This taxon: Elliptical; central area with one or two cycles of perforations and central hollow spine

Farinacci & Howe catalog pages: Perissocyclus + *

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:

CA: placolith, ca_disjunct, grill, pores, process, CROSS-POLARS: rim-unicyclic, V-prominent, R-prominent,

Lith 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 Danian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Early Oxfordian Substage (159.40-161.50Ma, base in Oxfordian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Neptune data: This is a higher taxon page so Neptune data is not plotted. See also: customisable plot Parent: Axopodorhabdaceae

References:

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). Lower Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 86-131. gs O

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: 19-6-2025

Taxon Search:

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10882 Go to Archive.is to create a permanent copy of this page - citation notes

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