Nannotax3 - ntax_main - Pontosphaera japonica

Citation: Pontosphaera japonica (Takayama 1967) Nishida, 1971

Basionym: Discolithina japonica Takayama 1967

Synonyms: Discolithina millepuncta Gartner, 1967 [according to Okada & McIntyre 1977]
Pontosphaera decorata von Salis (1994) [my interpretation - JRY 2015]

Distinguishing features:
Parent taxon (Pontosphaera): Coccoliths are muroliths, central area with variable number of perforations. V-units form narrow imbricate outer wall, R-units form inner wall and central-area.
This taxon: Rim flush with central-area pores very small (<0.1µm) often infilled during diagenesis.

Pores are very small (ca. 0.05µm), not visible in LM, in semi-regular array with ca. 10- 15 rows of pores on each side of the coccolith. Surrounding the central field of pores there is typically a zone of circular depressions and then a smooth zone.

Frada et al. (2009) showed that P. japonica forms combination coccospheres with a previously undescribed holococcolith. This is similar to Syracolithus schilleri (shown to be the holococcolith phase of Scyphosphara apsteinii) but without an outer rim of radially disposed crystallites.

Geological Range:
Last occurrence (top): Extant. Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within Miocene Epoch (5.33-23.03Ma, base in Aquitanian stage). Data source: [JRY rough estimate]

References:

Burns, D. A. (1973). Structural analysis of flanged coccoliths in sediments from the South West Pacific Ocean. Revista Española de Micropaleontología. 5(1): 147-160. gs O

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

Gartner, S. (1967a). Calcareous nannofossils from Neogene of Trinidad, Jamaica, and Gulf of Mexico. University of Kansas Paleontological Contributions, Papers. 29: 1-7. gs

Okada, H. & McIntyre, A. (1977). Modern coccolithophores of the Pacific and North Atlantic Oceans. Micropaleontology. 23(1): 1-55. gs

Reid, F. M. H. (1980). Coccolithophorids of the North Pacific Central Gyre with notes on their vertical and seasonal distribution. Micropaleontology. 26(2): 151-176. gs

Takayama, T. (1967). First report on nannoplankton of the Upper Tertiary and Quaternary of the southern Kwanto region, Japan. Jahrbuch der Geologischen Bundesanstalt. 110: 169-198. gs

von Salis, K. (1994). Some fossil “living coccolithophorid” species. Journal of Nannoplankton Research. 16(3): 109-114. gs

Winter, A. & Siesser, W. G. (1994). Atlas of living coccolithophores. In, Winter, A. & Siesser, W. G. (eds) Coccolithophores. Cambridge University Press, Cambridge 107-159. gs

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

Young, J. R., Geisen, M., Cros, L., Kleijne, A., Probert, I. & Ostergaard, J. B. (2003). A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research. S1: 1-132. gs

Pontosphaera japonica

References:

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