Nannoconaceae


Classification: Mesozoic -> Braarudosphaerales -> Nannoconaceae
Sister taxa: Braarudosphaeraceae, Nannoconaceae, Polycyclolithaceae, Other nannoliths with tangential c-axes,

Distinguishing features: Conical, globular or cylindrical nannoliths composed of plates spirally-arranged around an axial cavity or canal. Plate c-axes are arranged tangentially to the longitudinal axis.


Daughter taxa: (blue => in age window 0-800Ma) Granddaughter taxa
Long, narrow columnar nannoliths formed from stacks of calcite laths around a narrow axial canal. May occur as linked groups of multiple columns.

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.

Globular and stellate nannoliths formed of 5-8 segments of stacked elements. Nannoconus-like in side view.  

Taxonomy:

Citation: Nannoconaceae Deflandre, 1959
Rank: Family

Farinacci & Howe catalog pages: Nannoconaceae [no catalog entry yet]

Distinguishing features: Conical, globular or cylindrical nannoliths composed of plates spirally-arranged around an axial cavity or canal. Plate c-axes are arranged tangentially to the longitudinal axis.


Morphology remarks: For an explanation of general nannoconid morphology and terminology see van Niel (1994) and Young et al. (1997).

Evolution & Phylogeny: Faviconus has long been included in the Nannoconaceae on the grounds that it seems to be a less organised precursor. However, Hexalithus and Polycyclolithus represent alternative possible ancestors and the two possibilities are not obviously compatible. [editor's comment - JRY 2019]

Geological Range:
Last occurrence (top): at top of Campanian Stage (100% up, 72.1Ma, in Campanian stage). Data source: Total of range of species in this database
First occurrence (base): near top of Oxfordian Stage (89% up, 157.9Ma, in Oxfordian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 34-85. gs

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

Deflandre, G. (1959). Sur les nannofossiles calcaires et leur systématique. Revue de Micropaléontologie. 2: 127-152. gs

van Niel, B. E. (1994a). A review of the terminology used to describe the genus Nannoconus (calcareous nannofossil, incertae sedis. Cahiers de Micropaleontologie. 9(27-47): -. gs

Young, J. R. et al. (1997). Guidelines for coccolith and calcareous nannofossil terminology. Palaeontology. 40: 875-912. gs


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Nannoconaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 26-8-2019

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10717 Go to Archive.is to create a permanent copy of this page - citation notes



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