Nannotax3 - ntax_mesozoic

Nannotax3 - ntax_mesozoic - Nannoconus Nannotax3 - ntax_mesozoic - Nannoconus

Nannoconus

Classification: ntax_mesozoic -> Braarudosphaerales -> Nannoconaceae -> Nannoconus
Sister taxa: Faviconus, Nannoconus

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).	Nannoconus bermudezii Nannoconus dolomiticus Nannoconus farinacciae Nannoconus regularis Nannoconus steinmannii
	N. kamptneri group Pear-shaped and tapering nannoconids with wide central cavity (ct = 1-3 x wt).	Nannoconus aquitanicus Nannoconus boletus Nannoconus bonetii Nannoconus bronnimannii Nannoconus bucheri Nannoconus calpidomorphus Nannoconus colomii Nannoconus dauvillieri Nannoconus dislocatus Nannoconus globulus Nannoconus kamptneri Nannoconus oviformis Nannoconus vocontiensis Nannoconus wassallii Nannoconus 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	Nannoconus abundans Nannoconus alvus Nannoconus borealis Nannoconus concavus Nannoconus inornatus Nannoconus troelsenii
	N. truittii group Cylindrical, barrel-shaped or slightly tapering nannoconids with moderately wide central canals (ct ≈ wt).	Nannoconus cornuta Nannoconus donnatensis Nannoconus elongatus Nannoconus inconspicuus Nannoconus longus Nannoconus minutus Nannoconus multicadus Nannoconus planus Nannoconus quadriangulus Nannoconus quadricanalis Nannoconus 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)	Nannoconus carniolensis Nannoconus circularis Nannoconus fragilis Nannoconus grandis Nannoconus quadratus
	N. compressus group Relatively small (<~5µm), subcircular, elliptical or cylindrical nannoconids with relatively narrow canals (ct < wt).	Nannoconus compressus Nannoconus infans Nannoconus puer
	Nannoconus - atypical Atypical nannoconids, not fitting in any of the main groups	Nannoconus funiculus Nannoconus ligius Nannoconus magnadiscus Nannoconus nicholasii Nannoconus pseudoseptentrionalis Nannoconus sabinae
	Nannoconus sp. Specimens not identified to species level

Taxonomy:

Citation: Nannoconus Kamptner, 1931

taxonomic rank: Genus

Type species: Nannoconus steinmannii Kamptner, 1931

Synonyms: Brachiolithus Noël (1959)
Nannosphaeroidina Colom 1968

Farinacci & Howe catalog pages: Nannoconus + + * , Brachiolithus * , Nannosphaeroidina *

Morphology:

Nannoconids are particularly common in early Cretaceous Tethyan carbonates. Following abundance declines in the late Barremian to early Aptian they are only occassionally common in younger levels and became extinct in the Campanian. They can be difficult to work with and classify due to intraspecific variability, problems related to microscopical resolution of globose, three-dimensional objects, and poor preservation in the Tethyan limestones, where nannoconids are most common and from which most holotypes were figured. These problems, together with complex palaeobiogeographic patterns, have resulted in rather poor calibration of nannoconid bioevents. For an explanation of general nannoconid morphology and terminology see van Niel (1993, 1994) and Young et al. (1997).

Search data:

LITHS: nannolith-radiate, circular, hollow, cylindrical, CA: vacant, CROSS-POLARS: T-prominent,

Lith size: 3->55µm;
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 Campanian Stage (100% up, 72.2Ma, in Campanian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Tithonian Stage (143.10-149.24Ma, base in Tithonian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Neptune data: This is a higher taxon page so Neptune data is not plotted. See also: customisable plot Parent: Nannoconaceae

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 O

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

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