Nannotax3 - ntax_cenozoic - Gomphiolithus Nannotax3 - ntax_cenozoic - Gomphiolithus

Gomphiolithus


Classification: ntax_cenozoic -> Discoasterales -> Fasciculithaceae -> Gomphiolithus
Sister taxa: Diantholitha, Fasciculithus, Gomphiolithus, Lithoptychius, Tectulithus

Daughter taxa (time control age-window is: 0-800Ma)
Gomphiolithus magnicordis
Medium-sized species (H ca 7 µm, W ca 9 µm) with flat cylindrical outline, consisting of 20 to 30 wedges with a smooth outer surface and a large and deep distal depression with central body.
Gomphiolithus magnus
Large, cylindrical fasciculith with deep indentation on the distal surface. The proximal end is narrower with an abrupt shoulder  one quarter to  half way up the column, 

Taxonomy:

Citation: Gomphiolithus Aubry in Aubry et al. 2011
taxonomic rank: Genus
Type species: Fasciculithus magnus Bukry & Percival 1971

Distinguishing features:
Parent taxon (Fasciculithaceae): Conical or cylindrical discoasteralids consisting of 10-30 wedge-shaped, radially-arranged elements, in one to three superposed cycles.
This taxon: Fasciculiths formed of a single cycle, arguably with central body, deep cavity on the distal side, no fenestrae

Farinacci & Howe catalog pages: Gomphiolithus + *


Morphology:

Orientation: Romein (1979) used crystallographic orientation to determine the way-up of fasciculiths. On this basis he oriented the species now included in Gomphiolithus with the V-shaped depression distally. This scheme is used here, since, in our experience, crystallographic orientation is a conservative character of high value for tracing homology. Miniati et al. (2021) oriented Gomphiolithus the other way up, but without providing a clear explanation of why they did not use crystallographic orientation. [our interpretation JRY & R Howe 2022]


Phylogenetic relations

These are the ancestral fasciculiths according to Romein (1979) and separating them, as reccomended by Aubry et al. (2011), makes sense phylogenetically, if Fascilulithus (sensu stricto) evolved from Lithoptychius rather than from Gompholithus.

Search data:
LITHS: nannolith-radiate, circular, cylindrical, CROSS-POLARS: R-prominent,
Lith size: 6->10µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: Romein (1979), Perch-Nielsen (1985), Steurbaut & Sztrakos (2008), & Monechi et al. (2013) all give these species a similar restricted range in lower NP4
Last occurrence (top): at top of NP4 zone (100% up, 61.5Ma, in Selandian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NP4 zone (61.51-63.25Ma, base in Danian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:

Aubry, M. P., Bord, D. & Rodriguez, O. (2011). New taxa of the Order Discoasterales Hay 1977. Micropaleontology. 57(3): 269-287. gs

Miniati, F., Cappelli, C. & Monechi, S. (2021). Revised taxonomy and early evolution of fasciculiths at the Danian–Selandian transition. Journal of Micropalaeontology. 40: 101-144. gs O

Romein, A. J. T. (1979). Lineages in Early Paleogene calcareous nannoplankton. Utrecht Micropaleontological Bulletin. 22: 1-231. gs O


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Gomphiolithus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 26-5-2024

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=629 Go to Archive.is to create a permanent copy of this page - citation notes
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