Nannotax3 - ntax_mesozoic - Markalius neuquenensis Nannotax3 - ntax_mesozoic - Markalius neuquenensis

Markalius neuquenensis


Classification: ntax_mesozoic -> Heterococcoliths inc sedis -> placoliths inc sedis -> Markalius -> Markalius neuquenensis
Sister taxa: M. inversus, M. neuquenensis, M. vetulus, M. sp.

Distinguishing features:
Parent taxon (Markalius): Circular placoliths with moderately birefringent shields, a bright inner tube cycle and narrow or closed central areas.
This taxon: Like M.inversus but with a row of perforations on the tube


Taxonomy:

Citation: Markalius neuquenensis Guerra & Concheyro 2023
Taxonomic rank: species

Farinacci & Howe catalog pages: M. neuquenensis *

Distinguishing features:
Parent taxon (Markalius): Circular placoliths with moderately birefringent shields, a bright inner tube cycle and narrow or closed central areas.
This taxon: Like M.inversus but with a row of perforations on the tube


Morphology:

Diagnosis: A Markalius species characterized by a broad, birefringent tube cycle divided into four sectors in XPL, each with at least one small perforation. The coccolith shape is circular to subcircular and it is medium to large in size. The tube cycle width is similar or slightly greater than the rim/shield and there is no central opening. The tube cycle is brighter at the edges where it connects to the shield. [Guerra & Concheyro 2023]

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]

Search data:
LITHS: placolith, circular, CA: closed, pores, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
Lith size: 0->0µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NP1 zone (65.47-66.04Ma, top in Danian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within CC26 zone (66.04-67.82Ma, base in Maastrichtian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:

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


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Markalius neuquenensis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 14-1-2025

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=11419 Go to Archive.is to create a permanent copy of this page - citation notes
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