Distinguishing features: Nannoliths trilobate, formed of three petal-like elements and a central process.
Farinacci & Howe catalog pages: P. longistirpes *
Morphology: The elements are curved and so do not look like typical coccoliths, they are however formed of calcite as established by both chemical analysis and LM observations (Meier et al. 2014). The calcite c-axes are sub-vertical relative to the plates, and so the coccosphere shows radial c-axes (and is readily visible in LM)..
Size: Cell diameter 3.7-4.5 µm, lith diameter 3 to 3.8 µm.
Ecology & Biogeography: Appears to be confined to shelf seas, has been in seen in the Baltic Sea, North Sea and Irish Sea (Meier et al. 2014) also in the Bay of Biscay (Beaufort pers. comm.) and off Japan (Hagino pers. comm.)
Phylogenetic relations: No extant coccolithophores are obvious candidates for an evolutionary relationship with P. longistirpes and it does not show the characteristic rim/central area division of heterococcoliths. Hence it is regarded here as a nannolith of uncertain affinities. An intriguing possibility is that it might be related to Discoaster (Meier et al. 2014).
|Tags||LITHS: planolith, circular, CA: process, |
CSPH: equant, monomorphic, CROSS-POLARS: 1ou, V-prominent,
|Metrics||Lith size: 3->4µm; Segments: 3->3; Coccosphere size: 3.5->4.5µm; Liths per sphere: 6->8|
Data source notes: lith size from OD
Notes: The individual nannoliths are almost invisible in LM since they have sub-vertical c-axes hence it will be difficult to establish the fossil record.
Last occurrence (top): Extant Data source: present in the plankton (Meier et al. 2014)
First occurrence (base): within No known fossil record modern (0.00-0.00Ma, base in "Holocene" stage). Data source: no fossil records
Plot of occurrence data:
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