Nephrolithus frequens subsp. miniporus


Classification: ntax_mesozoic -> Podorhabdales -> Axopodorhabdaceae -> Nephrolithus -> Nephrolithus frequens -> Nephrolithus frequens subsp. miniporus
Sister taxa: N. frequens subsp. frequens, N. frequens subsp. miniporus

Distinguishing features: Reniform to elliptical subspecies of N. frequens with only two holes within the central area.


Taxonomy:

Citation: Nephrolithus frequens subsp. miniporus (Reinhardt & Górka 1967) Pospichal & Wise 1990
Rank: Sub-species
Basionym: Nephrolithus miniporus Reinhardt & Górka 1967
Taxonomic discussion: Pospichal & Wise 1990 (p.474) discuss and redscribe this sub-species in detail and emend the concept to only include forms with two pores. Ehrendorfer (1994) conducted a detailed morphometric study of very well-preserved Late Maastrichtian material and clearly showed that there was continuous variation between forms with 2 pores and those with more. He concluded that separation of the morphotypes as sub-species was artificial. However, given the stratigraphic utility of separting the form with 2 pores we recognise it here.

Farinacci & Howe catalog pages: N. miniporus *

Distinguishing features: Reniform to elliptical subspecies of N. frequens with only two holes within the central area.


Size: 4-7 µm (cf. Pospichal & Wise 1990, Ehrendorfer 1994)

Search data:
TagsLITHS: placolith, asymmetric, CA: ca_disjunct, plate, pores, closed, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
MetricsLith size: 4->7µm;
Data source notes: Pospichal & Wise 1990
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Maastrichtian Stage (66.04-72.05Ma, top in Maastrichtian stage). Data source: Burnett 1998
First occurrence (base): in mid part of UC20c subzone (50% up, 67.6Ma, in Maastrichtian stage). Data source: Burnett 1998

Plot of occurrence data:

References:

Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 132-199. gs V O

Ehrendorfer, T. W. (1994). The calcareous nannofossil species Nephrolithus frequens Gorka (1957) and its morphotypes. Journal of Paleontology. 68(2): 191-200. gs

Pospichal, J. J. & Wise, S. W. (1990b). Maestrichtian calcareous nannofossil biostratigraphy of Maud Rise ODP leg 113 sites 689 and 690, Weddell Sea. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 465-487. gs V O

Reinhardt, P. & Górka, H. (1967). Revision of some Upper Cretaceous Coccoliths from Poland and Germany. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 129(3): 240-256. gs

Thibault, N. (2010). Calcareous nannofossils from the boreal Upper Campanian- Maastrichtian chalk of Denmark. Journal of Nannoplankton Research. 31(1): 39-56. gs V O


nannotaxlogo400px

Nephrolithus frequens subsp. miniporus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-4-2021

Taxon Search:
Advanced Search

Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10800 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet on this page. Please do add comments if you spot any problems, or have information to share

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics