Nannoliths


Ancestry: Mesozoic -> Nannoliths
Sister taxa: Arkhangelskiales, Eiffellithales, Stephanolithiales, Podorhabdales, Watznaueriales, Nannoliths, Holococcoliths, Heterococcoliths inc sedis, Mesozoic non–coccoliths, hidden,

Short diagnosis: Nannofossils which show neither the rim structure of heterococcoliths nor the microcrystalline structure of holococcoliths.


Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Nannoliths constructed from five segments which form a pentalith (a five-sided plate); C-axes tangential to pentalith outline in plan view; individual crystal units show laminar ultrastructure.

Pentagonal liths, with narrow rim and granular central area plate. Dark image in LM.

Nannoliths with a truncated-cone-like morphology constructed from an outer rim of thin, elements joined along vertical sutures, and an inner core of numerous radial lamellae that may protrude distally.

Hemispherical to tall cylindrical nannoliths, with narrow walls constructed from one to several cycles of thin elements, enclosing a hollow central space; the nannolith tapers distally, and may have apical spines or processes.

Rod-shaped nannoliths.

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.

Nannoliths composed of two superposed wall cycles and a central-area which may be closed, open and vacant, or spanned by a diaphragm-like structure. Elements have tangential c-axis orientation.

Radiate nanoliths formed of multiple elements but lacking a central diaphragm

Nannolith genera without clear affinities to any other genera

Taxonomy:

Citation: Nannoliths
Rank: informal group

Farinacci & Howe catalog pages:

Short diagnosis: Nannofossils which show neither the rim structure of heterococcoliths nor the microcrystalline structure of holococcoliths.


Morphology remarks: The term nannolith appears to have been introduced by Haq (1978), it is also discussed in e.g. Young et al. (1997). The Mesozoic nannoliths are a very mixed grouping but include many biostratigraphically important taxa.

Geological Range:
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): within Norian Stage (209.46-228.35Ma, base in Norian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bown, P.R., (1998). Triassic. In: Bown, P.R. (Editor), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publication Series. Chapman & Hall, pp. 29-33.

Haq, B.U., (1978). Calcareous nannoplankton. In: Haq, B.U. and Boersma, A. (Editors), Introduction to marine micropaleontology. Elsevier, Amsterdam, pp. 79-108.

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


Nannotax3 - Mesozoic - Nannoliths by: Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 24-3-2017

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