Watznaueriaceae


Ancestry: Mesozoic -> Watznaueriales -> Watznaueriaceae
Sister taxa: Watznaueriaceae,

Short diagnosis: 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.


Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Regular placoliths
Elliptical watznaueriacean coccoliths with broad V-unit cycle, which results in a three tiered placolith structure. Moderately birefringent in XPL.

Circular watznaueriacean coccoliths.

Modified watznaueriacean coccoliths with one conical/flaring (proximal) shield with elements joined along oblique sutures, and a smaller, flatter (distal) shield with the principle elements joined along near radial sutures. Usually circular with a central opening.

Elliptical watznaueriacean coccoliths with central-area axial cross, with or without additional lateral bars. Cross usually spine bearing.

Elliptical watznaueriacean coccoliths with central-areas that are typically closed or narrow but may be spanned by transverse bar, bars or grill.

Elevated taxa
Watznaueriacean coccoliths with a tube-like/conical proximal shield.

High, cylindrical morphology with a peg-like distal cycle; possibly the isolated central part of Cyclagelosphaera deflandrei specimens which have lost the shields.

Medium to large, barrel-shaped coccoliths that are highly-birefringent and seen in both side and plan view.

Taxonomy:

Citation: Watznaueriaceae Rood et al., 1971
Rank: Family
Type species: Watznaueria Reinhardt, 1964.

Farinacci & Howe catalog pages:

Short diagnosis: 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.


Morphology remarks: Coccoliths are highly birefringent in XPL. Common, sometimes dominant, through most of the Mesozoic (Pliensbachian to Maastrichtian).

Geological Range:
Last occurrence (top): within Ypresian Stage (47.84-55.96Ma, top in Ypresian stage). Data source: Total of range of species in this database
First occurrence (base): within Hettangian Stage (199.30-201.30Ma, base in Hettangian 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. (Editor), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publication Series. Chapman & Hall, pp. 34-85.

Reinhardt, P., (1964). Einige Kalkflagellaten-Gattungen (Coccolithophoriden, Coccolithineen) aus dem Mesozoikum Deutschlands. Monatsberichte der Deutschen Akademie der Wissenschaften zu Berlin, 6: 749-759.

Rood, A.P.; Hay, W.W. & Barnard, T., (1971). Electron Microscope Studies of Oxford Clay Coccoliths. Eclogae Geologicae Helvetiae, 64: 245-272.


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

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