Distinguishing features:
Parent taxon (Nannoconaceae): 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.
This taxon: 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.
Daughter taxa (time control age-window is: 0-800Ma)![]() | Granddaughter taxa | ||||
N. steinmannii group Tapering nannoconids with narrow central canal (ct < wt). | |||||
N. kamptneri group Pear-shaped and tapering nannoconids with wide central cavity (ct = 1-3 x wt). | N. aquitanicus N. boletus N. bonetii N. bronnimannii N. bucheri N. calpidomorphus N. colomii N. dauvillieri N. dislocatus N. globulus N. kamptneri N. oviformis N. vocontiensis N. wassallii N. wintereri | ||||
![]() | ![]() | ![]() | N. abundans group Cylindrical nannoconids with thin, low-angled wall cycles and relatively narrow canal (ct < wt); also may have apical and/or antapical flanges and/or bulbous base | ||
![]() | ![]() | ![]() | N. truittii group Cylindrical, barrel-shaped or slightly tapering nannoconids with moderately wide central canals (ct ≈ wt). | N. cornuta N. donnatensis N. elongatus N. inconspicuus N. longus N. minutus N. multicadus N. planus N. quadriangulus N. quadricanalis N. truittii | |
![]() | ![]() | ![]() | N. circularis group Cylindrical nannoconids with thin walls (~1.5µm or less), thin, low-angled wall cycles and very wide central cavity (typically ct >3x wt) | ||
![]() | ![]() | ![]() | ![]() | N. compressus group Relatively small (<~5µm), subcircular, elliptical or cylindrical nannoconids with relatively narrow canals (ct < wt). | |
Nannoconus - atypical Atypical nannoconids, not fitting in any of the main groups | |||||
![]() | ![]() | Nannoconus sp. Specimens not identified to species level |
Taxonomy:
Nannosphaeroidina Colom 1968
Farinacci & Howe catalog pages: Nannoconus + + * , Brachiolithus * , Nannosphaeroidina *
Distinguishing features:
Parent taxon (Nannoconaceae): 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.
This taxon: 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.
Morphology:
Size:
Tags | LITHS: nannolith-radiate, circular, cylindrical, hollow, CA: vacant, CROSS-POLARS: T-prominent, |
Metrics | Lith size: 3->55µm; Data source notes: size range of included species |
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): 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:
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 O Kamptner, E. (1931). Nannoconus steinmanni novo gen., novo spec., ein merkwurdiges gesteinbildendes Mikrofossil aus dem jungeren Mesozoikum der Alpen. Paläontologische Zeitschrift. 13: 288-298. gs van Niel, B. E. (1992). New observations on the morphology of Nannoconus. In, Hamrsmid, B. & Young, J. R. (eds) Nannoplankton Research, Proceedings of the 4th INA Conference, Prague 1991, vol II. Knihovnicka ZPN. 14a: 73-85. gs V O van Niel, B. E. (1994a). A review of the terminology used to describe the genus Nannoconus (calcareous nannofossil, incertae sedis). Cahiers de Micropaléontologie. 9: 27-47. gs Young, J. R. et al. (1997). Guidelines for coccolith and calcareous nannofossil terminology. Palaeontology. 40: 875-912. gs V OReferences:
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Nannoconus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 29-5-2022
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10718 Go to Archive.is to create a permanent copy of this page - citation notes |
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