Distinguishing features: Parent taxon (ntax_mesozoic): Mesozoic nannofossils - Cenozoic and extant taxa are in a separate module This taxon: Placolith (or modified placolith) coccoliths with a distal cycle of clockwise-imbricating elements. R-units well developed, forming proximal and distal shield elements with opposite senses of imbrication; V-units typically form a narrow distal cycle near the inner edge of the shield.
Daughter taxa (time control age-window is: 0-800Ma)
Granddaughter taxa
Watznaueriaceae Placoliths or modified placoliths with R-unit well developed, forming proximal and distal shield elements with opposite senses of imbrication; the V-unit typically forms a narrow distal cycle near the inner edge of the shield. Central-area structures are typically disjunct. Birefringent LM image, in which the V-unit cycle appears only as a thin, dark line.
Distinguishing features: Parent taxon (ntax_mesozoic): Mesozoic nannofossils - Cenozoic and extant taxa are in a separate module This taxon: Placolith (or modified placolith) coccoliths with a distal cycle of clockwise-imbricating elements. R-units well developed, forming proximal and distal shield elements with opposite senses of imbrication; V-units typically form a narrow distal cycle near the inner edge of the shield.
Morphology: Placoliths or modified placoliths with R-unit well developed, forming proximal and distal shield elements with opposite senses of imbrication; the V-unit typically forms a narrow distal cycle near the inner edge of the shield. Central-area structures are typically disjunct. Birefringent LM image, in which the V-unit cycle appears only as a thin, dark line.
Search data:
: placolith,
Lith size: 0->0µm;
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 NP10 zone (100% up, 54.2Ma, in Ypresian stage). Data source: Total of ranges of the species in this database First occurrence (base): within Pliensbachian Stage (184.20-192.90Ma, base in Pliensbachian 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. For the customisable plot option go to a genus page Parent: ntax_mesozoic
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. gsO
Bown, P. R. (1987a). Taxonomy, evolution, and biostratigraphy of Late Triassic-Early Jurassic calcareous nannofossils. Special Papers in Palaeontology. 38: 1-118. gs
Young, J. R. & Bown, P. R. (1997). Proposals for a revised classification system for calcareous nannoplankton. Journal of Nannoplankton Research. 19(1): 15-47. gs
Watznaueriales compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 11-2-2025
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