Nannotax3 - ntax_mesozoic - N. compressus group

N. compressus group


Classification: ntax_mesozoic -> Braarudosphaerales -> Nannoconaceae -> Nannoconus -> N. compressus group
Sister taxa: N. steinmannii group, N. kamptneri group, N. abundans group, N. truittii group, N. circularis group, N. compressus group, Nannoconus - atypical, N. sp.

Distinguishing features:
Parent taxon (Nannoconus): Conical, globular or cylindrical nannoliths composed of plates spirally-arranged around an axial cavity (~>1µm in width) or canal (~<1µm in width). Plate c-axes are arranged tangentially to the longitudinal axis.
This taxon: Relatively small (<~5µm), subcircular, elliptical or cylindrical nannoconids with relatively narrow canals (ct < wt).


Daughter taxa (time control age-window is: 0-800Ma)
Nannoconus compressus
Rectangular to oval with narrow canal
Nannoconus infans
Minute to medium sized (1-6µm, typically 2-3µm) nannoconid with square, rectangular or oval outline and very narrow canal.
Nannoconus puer
Elliptical to subcircular with relatively narrow canal (less than wall thickness).

Taxonomy:

Citation: N. infans group
Rank: species group
Taxonomic discussion: informal grouping first used here. The species N. erbae and N. infans were placed in this group but are now considered to belong to Polycostella, following Varol & Bowman (2019).

Farinacci & Howe catalog pages: N. infans group [no catalog entry yet]

Distinguishing features:
Parent taxon (Nannoconus): Conical, globular or cylindrical nannoliths composed of plates spirally-arranged around an axial cavity (~>1µm in width) or canal (~<1µm in width). Plate c-axes are arranged tangentially to the longitudinal axis.
This taxon: Relatively small (<~5µm), subcircular, elliptical or cylindrical nannoconids with relatively narrow canals (ct < wt).

Search data:
TagsLITHS: nannolith-radiate, circular, cylindrical, hollow, CA: vacant, CROSS-POLARS: T-prominent,
MetricsLith size: 3->8µm;
Data source notes: size range of included species
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of Berriasian Stage (100% up, 139.4Ma, in Berriasian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Tithonian Stage (0% up, 152.1Ma, in Kimmeridgian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Casellato, C. E. (2010). Calcareous nannofossil biostratigraphy of Upper Callovian - Lower Berriasian successions from the Souhern Alps, North Italy. Rivista Italiana di Paleontologia e Stratigrafia. 116(3): 357-404. gs V O

Varol, O. & Bowman, A. R. (2019). Taxonomic revision of selected Late Jurassic (Tithonian) calcareous nannofossils and the application of mobile mounting. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 291: 65-87. gs


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N. compressus group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 22-1-2022

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10713 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (1)

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Cristina Casellato (Università degli Studi di Milano, Italy)
Hello,
I just want to correct the name: Casellato, not Casselato.
my best regards
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Jeremy Young (UCL, UK)
OK - I have corrected that now and also on a couple of other pages. To heck this you can use the google search box on the search page which allows you to check quickly for everywhere a name occurred on the site the last itme google checked it.
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