Taxonomy:
Distinguishing features:
Parent taxon (Markalius): Circular placoliths with moderately birefringent shields, bright inner tube cycle and narrow or closed central areas.
This taxon: Like M.inversus but with a row of perforations on the tube
Farinacci & Howe catalog pages: M. neuquenensis *
Morphology:
Remarks: M. neuquenensis is distinguished from other Markalius species by the wide tube cycle with perforations. Markalius inversus and M. latus show no perforations. In M. walvisensis, the tube cycle is much reduced and M. apertus has a central area opening. [Guerra & Concheyro 2023]
| LITHS: placolith, circular, elliptical, CA: pores, closed, CROSS-POLARS: rim-unicyclic, V-prominent, R-prominent, |
| Lith size: 6->9µm; Data source notes: Guerra & Concheyro 2023 - and limits extended |
Geological Range:
Last occurrence (top): within NP1 zone (65.47-66.04Ma, top in Danian stage). Data source: Guerra & Concheyro 2023
First occurrence (base): within CC26 zone (66.04-67.82Ma, base in Maastrichtian stage). Data source: Guerra & Concheyro 2023
Plot of occurrence data:
Bown, P. R., Kim, H. & Gibbs, S. J. (2023). Danian calcareous nannofossil evolution and taxonomy with focus on sites from the North Atlantic Ocean (IODP Expedition 342, Sites U1403 and U1407). Journal of Nannoplankton Research. 41(2): 110-157. gs O Guerra, R. M. & Concheyro, A. (2023). A new Markalius species from the Cretaceous/Paleogene boundary of the Neuquén Basin (Argentina). Journal of Nannoplankton Research. 41(2): 106-109. gs References:

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Markalius neuquenensis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-11-2025
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1813 Go to Archive.is to create a permanent copy of this page - citation notes |
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