Small to very small (<3µm), central area very narrow
Medium sized (4-6µm) with narrow central area and birefringent cross. Short-axis crossbar brighter than long-axis crossbar.
Distinguishing features:
Parent taxon (Biscutaceae): Regular placoliths; rim broad, central area relatively narrow, with variable central structures.
The distal shield is formed from V-units and the proximal shield and tube cycle are formed from R-units.
This taxon: Elliptical with slits between shield elements and axial cross
| Daughter taxa (time control age-window is: 0-800Ma) | ||||
| | | | Jimenezberrocosoia birchiae Small to very small (<3µm), central area very narrow |
| | | | Jimenezberrocosoia bosunensis Medium sized (4-6µm) with narrow central area and birefringent cross. Short-axis crossbar brighter than long-axis crossbar. |
Taxonomy:
Taxonomic discussion: This genus has central-area features similar to certain species of Sollasites Black, 1967, but is distinct from Sollasites because of the distinctive rim slits. [Lees & Bown 2016]
Farinacci & Howe catalog pages: Jimenezberrocosoia
Distinguishing features:
Parent taxon (Biscutaceae): Regular placoliths; rim broad, central area relatively narrow, with variable central structures.
The distal shield is formed from V-units and the proximal shield and tube cycle are formed from R-units.
This taxon: Elliptical with slits between shield elements and axial cross
Biscutacean placolith coccoliths with slits between the elements of the distal shield. The narrow to moderately wide, open, elliptical central-areas are spanned by distinct structures, comprising an axial cross and accessory bars. The proximal shield comprises a rim of elongated, widely-spaced elements radiating from the central tube-cycle. [Lees & Bown 2016]
Morphology:
| Tags | LITHS: placolith, elliptical, CA: concentric-ring(s), cross-axial, ca_disjunct, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent, |
| Metrics | Lith size: 2->6µm; Data source notes: size range of included species |
Geological Range:
Last occurrence (top): at top of Coniacian Stage (100% up, 86.3Ma, in Coniacian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Aptian Stage (25% up, 123Ma, in Aptian stage). Data source: Total of range of species in this database
Plot of occurrence data:
References:
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Jimenezberrocosoia compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-1-2022
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10535 Go to Archive.is to create a permanent copy of this page - citation notes |
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