Nannotax3 - ntax_mesozoic - Gartnerago margaritatus

Gartnerago margaritatus

Classification: ntax_mesozoic -> Arkhangelskiales -> Kamptneriaceae -> Gartnerago -> Gartnerago margaritatus
Sister taxa: G. obliquum, G. segmentatum, G. costatum, G. diversum ⟩⟨ G. stenostaurion, G. clarusora, G. waszczakii ⟩⟨ G. chiasta, G. margaritatus, G. praeobliquum ⟩⟨ G. coxalliae, G. nanum, G. ponticula, G. theta, G. sp.


Citation: Gartnerago margaritatus Blair & Watkins 2009
Rank: Species

Farinacci & Howe catalog pages: G. margaritatus *


This ellipsoidal coccolith has a thin, three-tiered rim structure and a delicate, axial cross. The proximal rim is extremely thin (<0.3 mm) and is very dark in LM. The median cycle is very bright and is composed of a series of individual calcite elements that resemble glass beads or pearls in cross-polarized and phase contrast light. This median rim cycle contains between 32 and 40 crown elements. The thin distal rim is inconspicuous in LM. [Blair & Watkins 2009]
The central plate contains a thin axial cross that extends to the proximal rim. This axial cross is demarcated by a series of near axial sutures. The crossbars are slightly offset from the major and minor axes and are composed of 2 thin (<1 mm in width) bar elements. [Blair & Watkins 2009]
This species can be easily separated from most Gartnerago species by its small size, distinct ‘‘beaded’’ median rim cycle, and thin axial cross structure. Gartnerago clarusora, also exhibits a similar size and a beaded median rim cycle, however, lacks a central cross structure. The crowned rim composed of bead-like elements is seen most clearly in phase contrast light [Blair & Watkins 2009]


Ecology & Biogeography

Biology & life-cycles

Phylogenetic relations

Search data:
LITHS: placolith, elliptical, CA: cross-axial, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
Lith size: 4->7µm;
Data source notes: Mean width of original description +/- 1.5 µm
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Santonian Stage (83.64-86.26Ma, top in Santonian stage). Data source: Blair & Watkins 2009
First occurrence (base): within Coniacian Stage (86.26-89.77Ma, base in Coniacian stage). Data source: Blair & Watkins 2009

Plot of occurrence data:


Blair, S. A. & Watkins, D. K. (2009). High-resolution calcareous nannofossil biostratigraphy for the Coniacian/Santonian Stage boundary, Western Interior Basin. Cretaceous Research. 30(2): 367-384. gs


Gartnerago margaritatus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 30-11-2022

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

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