Pontosphaera japonica HOL


Classification: ntax_cenozoic -> Holococcoliths -> septate -> Pontosphaera japonica HOL
Sister taxa: C. leptoporus subsp. quadriperforatus HOL, S. apsteinii HOL, P. japonica HOL, S. sp. type A, S. sp. type B, S. bicorium

Taxonomy:

Citation: Pontosphaera japonica (Takayama 1967) Nishida, 1971 HOL
Rank: Species
Taxonomic discussion: This holococcolith morphotype was not prevously described, probably because any spcimens observed were mistaken for similar species such as Scyphosphaera apsteinii HOL (formerly Syracolithus schilleri) or some Helicosphaera holococcoliths (especially the perforate form formerly known as Syracolithus confusus).

Distinguishing features: Solid, disk-shaped coccolith with several irregular deep depressions; formed of single block of crystalites with sub-vertical c-axes; no outer wall/tube; one or two irregular knobs on long axis.

Farinacci & Howe catalog pages: P. japonica HOL [no catalog entry yet]


Morphology: Resembles Helicosphaera carteri HOL perforate type (aka Syracolithus confusus) but crystallites are arranged in hexagonal array with c-axes vertical (so dark in plan view in cross-polars). Also larger, depressions less regular, and has one or two irregular central bosses rather than a single pyramidal boss.
Also resembles Scyphosphaera apsteinii HOL (aka Syracolithus schilleri) but lacks outer tube cycle with radial c-axes and is formed of a single mass of crystallites with depressions rather than having clearly-developed septae.


Biology & life-cycles: Several good combination coccospheres with Pontosphaera japonica HET recorded by Frada et al. 2009 in SEM and LM, from a single sample collected in the Tyrhennian Sea (Westerm Mediterranean).

See also: Pontosphaera japonica ;

Search data:
TagsLITHS: holococcolith, elliptical, CA: pores,
CSPH: equant, monomorphic, CROSS-POLARS: V-prominent,
MetricsLith size: 3.5->4µm; Coccosphere size: 9->12µm;
Data source notes: lith size from Frada et al. 2009; csph size from illustrated specs
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): Extant Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within No known fossil record modern (0.00-0.00Ma, base in "Holocene" stage). Data source: [JRY rough estimate]

Plot of occurrence data:

References:

Frada, M., Percopo, I., Young, J. R., Zingone, A., de Vargas, C. & Probert, I. (2009). First observations of heterococcolithophore-holococcolithophore life cycle combinations in the family Pontosphaeraceae (Calcihaptophycideae, Haptophyta). Marine Micropaleontology. 71(1): 20-27. gs

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Pontosphaera japonica HOL compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-7-2021

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