Nannotax3 - ntax_main - Octocyclus Nannotax3 - ntax_main - Octocyclus

Octocyclus


Classification: ntax_main -> Mesozoic nannofossils -> Podorhabdales -> Axopodorhabdaceae -> Octocyclus
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)
Octocyclus magnus
Very large (>12 µm)
Octocyclus reinhardtii
Large (8-12 µm)
Octocyclus sp.
Specimens not identified to species level

Taxonomy:

Citation: Octocyclus Black, 1972
Taxonomic rank: genus
Type species: Octocyclus magnus Black, 1972.
Taxonomic discussion: Note that although Octocyclus and Octopodorhabdus are very similar they occur respectively in the Late Cretaceous and Jurassic, so it unlikely that they are directly related

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 spanned by eight bars delineating eight large perforations arranged either side of the long axis.

Farinacci & Howe catalog pages: Octocyclus *

Search data:
CA: placolith, ca_disjunct, grill, pores, process, CROSS-POLARS: rim-bicyclic, V-prominent,
Lith size: 8->15µm;
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 Albian Stage (100.50-113.20Ma, base in Albian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:

Black, M. (1972a). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 1). Palaeontographical Society Monograph. 126: 1-48. 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


nannotaxlogo400px

Octocyclus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 19-6-2025

Taxon Search:
Advanced Search

Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10808 Go to Archive.is to create a permanent copy of this page - citation notes



Add Comment

* Required information
Captcha Image

Comments

No comments yet. Be the first!