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Nannotax3 - ntax_cenozoic - Triquetrorhabdulus Nannotax3 - ntax_cenozoic - Triquetrorhabdulus

Triquetrorhabdulus


Classification: ntax_cenozoic -> Nannolith families inc sed -> Ceratolithaceae -> Triquetrorhabdulus
Sister taxa: Amaurolithus, Ceratolithus, Nicklithus ⟩⟨ Orthorhabdus, Triquetrorhabdulus ⟩⟨ Nivisolithus

Daughter taxa (time control age-window is: 0-800Ma)Granddaughter taxa
Triquetrorhabdulus carinatus
Elongate (up to 50µm). All three blades identical, without ridges.
Triquetrorhabdulus longus

Triquetrorhabdulus challengeri
Short broad species with two wide blades bearing one to four subsidiary ridges parallel to a shorted median lath. Optic axis parallel to length.

Triquetrorhabdulus milowii
Short (8-15µm), broad (5-8µm) species of Triquetrorhabdulus with curved sides. All blades similar.

Triquetrorhabdulus nanhaiensis
Like T. milowii but with two long spines, one at obtuse angle to main body

Triquetrorhabdulus sp.
Specimens which cannot be assigned to established species

Taxonomy:

Citation: Triquetrorhabdulus Martini 1965 emend Young & Bown 2014
Taxonomic rank: genus
Type species: Triquetrorhabdulus carinatus Martini 1965
Taxonomic discussion: This genus was emended by Young & Bown (2014) and species with c-xes perpendicular to the length of the nannolith were transferred to Orthorhabdus.

Distinguishing features:
Parent taxon (Ceratolithaceae): Horseshoe-shaped rod-shaped nannoliths and simple hoop-coccoliths formed in one phase of life cycle, planolith heterococcoliths in the other.
This taxon: Elongate, tri-radiate nannoliths formed of a single calcite crystal with the c-axis parallel to the length of the nannolith. Nannolith straight with bilateral or trilateral symmetry. Shows high birefringence.

Farinacci & Howe catalog pages: Triquetrorhabdulus + *


Phylogenetic relations

The species included in the genus have similar morphologies and overlapping ranges.

Search data:
LITHS: nannolith-other, rod-shaped, CROSS-POLARS: R-prominent, 1ou,
Lith size: 8->50µm; Segments: 3->3;
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 NN6 zone (100% up, 11.9Ma, in Serravallian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NP24 zone (26.84-29.62Ma, base in Rupelian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:

Martini, E. (1965). Mid-Tertiary calcareous nannoplankton from Pacific deep-sea cores. Colston Papers. 17: 393-411. gs O

Young, J. R. & Bown, P. R. (2014). Some emendments to calcareous nannoplankton taxonomy. Journal of Nannoplankton Research. 33(1): 39-46. gs

Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 225-265. gs


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Triquetrorhabdulus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 17-3-2025

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1437 Go to Archive.is to create a permanent copy of this page - citation notes
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