Chiasmolithus oamaruensis


Classification: ntax_cenozoic -> Coccolithales -> Coccolithaceae -> Chiasmolithus -> C. bidens group -> Chiasmolithus oamaruensis
Sister taxa: C. altus, C. bidens, C. edentulus, C. eoaltus, C. eograndis, C. expansus, C. grandis, C. medius, C. modestus, C. oamaruensis, C. solitus

Taxonomy:

Citation: Chiasmolithus oamaruensis (Deflandre, in Deflandre & Fert, 1954) Hay et al., 1966
Rank: Species
Basionym: Tremalithus oamaruensis Deflandre in Deflandre & Fert, 1954

Distinguishing features: Large to very large Chiasmolithus with broad centro-distal cycle, wide central area and straight, narrow, symmetrical diagonal bars, which join at a relatively acute angle along the minor axis.

Farinacci & Howe catalog pages: T. oamaruensis *


Phylogenetic relations: Firth & Wise (1992) discussed intergradations between Chiasmolithus oamaruensis, C. altus and C. expansus. Persico & Villa (2008) discuss intergradations between Chiasmolithus oamaruensis, C. altus, C. eoaltus and C. solitus

Search data:
TagsLITHS: placolith, elliptical, CA: ca_disjunct, diagonal cross,
CSPH: equant, monomorphic, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
MetricsLith size: 10->20µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: Older stratigraphic range (NP16) has been reported at high southern latitudes (Persico & Villa, 2008, JNR).
Last occurrence (top): within NP22 zone (32.02-32.92Ma, top in Rupelian stage). Data source: Perch-Nielsen 1985b
First occurrence (base): at base of NP18 zone (0% up, 37.3Ma, in Priabonian stage). Data source: zonal marker (see Perch-Nielsen 1985)

Plot of occurrence data:

References:

Bown, P. R. & Dunkley Jones, T. (2012). Calcareous nannofossils from the Paleogene equatorial Pacific (IODP Expedition 320 Sites U1331-1334). Journal of Nannoplankton Research. 32(2): 3-51. gs V O

de Kaenel, E. & Villa, G. (1996). Oligocene-Miocene calcareous nannofossil biostratigraphy and paleoeecology from the Iberian Abyssal Plain. Proceedings of the Ocean Drilling Program, Scientific Results. 149: 79-145. gs V O

Deflandre, G. & Fert, C. (1954). Observations sur les coccolithophoridés actuels et fossiles en microscopie ordinaire et électronique. Annales de Paléontologie. 40: 115-176. gs

Fioroni, C., Villa, G., Persico, D., Wise, S. W. & Pea, L. (2012). Revised middle Eocene-upper Oligocene calcareous nannofossil biozonation for the Southern Ocean. Revue de Micropaléontologie. 55(2): 53-70. gs

Firth, J. V. & Wise, S. W. (1992). A preliminary study of the evolution of Chiasmolithus in the Middle Eocene to Oligocene of sites 647 and 748. Proceedings of the Ocean Drilling Program, Scientific Results. 120: 494-508. gs V O

Hay, W. W., Mohler, H. P. & Wade, M. E. (1966). Calcareous nannofossils from Nal'chik (northwest Caucasus). Eclogae Geologicae Helvetiae. 59: 379-399. gs V O

Perch-Nielsen, K. (1971c). Elektronenmikroskopische untersuchungen an Coccolithen und verwandten Formen aus dem Eozan von Danemark. Biologiske Skrifter, Kongelige Danske Videnskabernes Selskab. 18(3): 1-76. gs

Perch-Nielsen, K. (1977a). Albian to Pleistocene calcareous nannofossils from the Western South Atlantic, DSDP Leg 39. Initial Reports of the Deep Sea Drilling Project. 39: 699-823. gs V O

Perch-Nielsen, K. (1985a). Cenozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 427-555. gs

Persico, D. & Villa, G. (2008). A new Eocene Chiasmolithus species: hypothetical reconstruction of its phyletic lineage. Journal of Nannoplankton Research. 30(1): 23-33. gs V O

Shamrock, J. L. & Watkins, D. K. (2012). Eocene calcareous nannofossil biostratigraphy and community structure from Exmouth Plateau, Eastern Indian Ocean (ODP Site 762). Stratigraphy. 9(1): 1-11. gs

Varol, O. (1998). Palaeogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 200-224. gs

Wei, W. & Wise, S. W. (1990b). Middle Eocene to Pleistocene calcareous nannofossils recovered by Ocean Drilling Program leg 113 in the Weddell Sea. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 639-666. gs V O

Wise, S. W. (1983). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 71 in the Falkland Plateau region, Southwest Atlantic Ocean. Initial Reports of the Deep Sea Drilling Project. 71: 481-550. gs V O


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Chiasmolithus oamaruensis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 23-1-2021

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=276 Go to Archive.is to create a permanent copy of this page - citation notes



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Juan P. Pérez Panera (Los Talas, Argentina)

Complete name of this species should be Chiasmolithus oamaruensis (Deflandre in Deflandre and Fert, 1954) Hay et al., 1966, to keep nannotax style.

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Jeremy Young (Tonbridge, UK)

yes - indeed. I've changed that now, thanks Jeremy

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