Nannotax3 - ntax_Farinacci - Trochoaster concavus

Original descriptions of taxa. For coccolithophores, and many calcispheres, these are pages from the Farinacci & Howe Catalog of Calcareous Nannofossils. In other cases (e.g. non-calcifying haptophytes) the data is directly compiled on this site. The "Catalogue of Calcareous Nannofossils" was originally compiled by Prof A. Farinacci 1969-1989, since 2000 it has been updated and extended by Richard Howe - see The Farinacci and Howe Catalog - an Introduction.
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Citation: Trochoaster concavus Bona 1964

Type age (chronostrat): Tortonian

Standardised type level: 123_UPPER MIOCENE

Farinacci catalog page (& compiler): 9236

Current citation: Lithostromation obscurum (Martini 1958) Martini 1970

Original descrition: Sechsarmiges Kalkkörperchen. In Planansicht ragen die drei Arme von der Mittelebene auf, so dass durch das Objektiv des Mikroskopes penetrierend, entweder nur die unteren, oder nur die oberen Arme scharf eingestellt werden können. Die Arme bilden miteinander einen Winkel von 120. Untere Arme im Verhältnis zu den oberen um 60° abweichend. Obere und untere dreieckige Platten stark konkav verlaufend. Ihre Kanten sind stark gebogen. Die inneren Bögen, sowie die dazwischen sitzenden Fenster sind kaum wahrnehmbar. Sie weisen schein- bar eher eine netzartige Struktur auf. Das kreisförmige, zentrale Fenster ist deutlich zu sehen. Das grösste Durchmesser des Plättchens beträgt 14 µm

Translation (from Google translate): Six-armed calcareous-body. In plan view, the three arms project from the mid-plane, so that only the lower arms, or only the upper arms, can be adjusted by the lens of the microscope. The arms form an angle of 120° with each other. Lower arms differ from the upper ones by 60°. Upper and lower triangular plates are strongly concave. Their edges are strongly bent. The inner arches, as well as the windows between them, are barely perceptible. They appear to have a net-like structure. The circular, central window is clearly visible. The largest diameter of the wafer is 14 μm

References:

Bona, J. (1964). Coccolithophorida-vizsgalatok a meceski retegekben (Coccolithopohriden-Unntersuchungen in der neogen Schichtenfolge des Meeskggerbirges). Földtani Közlöny - Bulletin of the Hungarian Geological Society. 94: 121-131. gs

CATALOG - Trochoaster concavus

References:

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