Tripinnalithus


Classification: Mesozoic -> Nannoliths inc sedis -> Nannoliths inc sed - other -> Tripinnalithus
Sister taxa: Ceratolithina, Ceratolithoides, Liliasterites, Marthasterites, Orthogonoides, Rhomboaster, Tripinnalithus, Watkinsia,

Distinguishing features: Elongate to diamond nannoliths with triradiate cross-section, c-axis parallel to nannolith length.


Daughter taxa: (blue => in age window 0-800Ma)
Diamond-shaped nannolith formed from three triangular blades that are widest towards the blunter end. The whole nannolith is highly birefringent when oriented at 45° to the polarising directions (when the vertically standing blade reaches blue birefringence), and extinct when oriented parallel with the polarisers, i.e. the c-axis is parallel to the length.
Specimens not identified to species level

Taxonomy:

Citation: Tripinnalithus Young & Bown 2014
Rank: Genus
Type species: Triquetrorhabdulus? shetlandensis Perch-Nielsen, 1988
Synonyms: Triquetrorhabdulus? Martini 1965 sensu Perch-Nielsen 1988
Notes & discussion: Perch-Nielsen 1988 described a Lower Cretaceous species T. shetlandensis which she tentatively ascribed to Triquetrorhabdulus. The new name Tripinnalithus was proposed by Young & Bown (2014) since there is a gap of ca 100Ma between the occurrence of T. shetlandensis and the first occurrence of Triquetrorhabdulus in the Oligocene.

Farinacci & Howe catalog pages: Tripinnalithus *

Distinguishing features: Elongate to diamond nannoliths with triradiate cross-section, c-axis parallel to nannolith length.

Geological Range:
Last occurrence (top): at top of Valanginian Stage (99% up, 133.9Ma, in Valanginian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Valanginian Stage (17% up, 138.5Ma, in Valanginian stage). Data source: Total of range 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

Perch-Nielsen, K. (1988). New Lower Cretaceous calcareous nannofossil species from England. INA Newsletter. 10(1): 30-37. gs

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


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Tripinnalithus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-10-2019

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=11249 Go to Archive.is to create a permanent copy of this page - citation notes



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