Cruciplacolithus tarquinius

Classification: ntax_cenozoic -> Coccolithales -> Coccolithaceae -> Cruciplacolithus -> Cruciplacolithus tarquinius
Sister taxa: C. neohelis, C. kanungoi ⟩⟨ C. cruciformis, C. flavius, C. klausii, C. nishii, C. tarquinius ⟩⟨ C. asymmetricus, C. edwardsii, C. frequens ⟩⟨ C. intermedius, C. primus, C. subrotundus, C. tenuis ⟩⟨ C. filigranus, C. inseadus, C. latipons, C. sp.


Citation: Cruciplacolithus tarquinius Roth & Hay in Hay et al. 1967
Rank: Species
Synonyms: Cruciplacolithus nebulosus Shamrock & Watkins 2012 [my interpretation Young 2015 - Roth's holotype of C. tarquinius perfectly matches this species]
Stauronertha tarquinius (Hay and Roth in Hay et al., 1967) Aubry, in Aubry & Bord 2009 [NB The reason for including this species in Stauronertha, which is based on C. neohelis, is not given]
Taxonomic discussion: Cruciplacolithus tarquinius is not a well-established species but the type illustration is very clear.

Distinguishing features: Medium sized Eocene-Oligocene Cruciplacolithus with delicate axial cross

Farinacci & Howe catalog pages: C. tarquinius * , C. nebulosus *

Morphology: "The central cross is extremely delicate and may be absent even in relatively well-preserved material, but can be indicated by the four, birefringent points of attachment that remain along the collar." It "can be readily differentiated from other species of Cruciplacolithus by size and stratigraphic range, as well as the distinct, ‘fuzzy’ appearance of the shield." It "can be differentiated from Bramletteius serraculoides, which also bears a delicate axial cross, by the notably wider shield of the former." - from description of C. nebulosus by Shamrock & Watkins (2012)

Search data:
TagsLITHS: placolith, elliptical, CA: cross-axial, ca_disjunct,
CSPH: equant, monomorphic, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
MetricsLith size: 4->7µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Oligocene Epoch (23.03-33.89Ma, top in Chattian stage). Data source: original description
First occurrence (base): within NP14a subzone (47.84-49.11Ma, base in Ypresian stage). Data source: Shamrock & Watkins 2012

Plot of occurrence data:


Hay, W. W., Mohler, H. P., Roth, P. H., Schmidt, R. R. & Boudreaux, J. E. (1967). Calcareous nannoplankton zonation of the Cenozoic of the Gulf Coast and Caribbean-Antillean area, and transoceanic correlation. Transactions of the Gulf-Coast Association of Geological Societies. 17: 428-480. gs V O

Jones, A. P. & Dunkley Jones, T. (2020). Middle Eocene to Early Oligocene calcareous nannofossils from the Nanggulan Formation, Java, Indonesia. Journal of Nannoplankton Research. 30(1): 57-79. 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


Cruciplacolithus tarquinius compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-2-2021

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Short stable page link: Go to to create a permanent copy of this page - citation notes

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