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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Original Description This genus is introduced for dome-shaped, porous nannoliths, consisting of a hollow construction of bifurcating ribs, which in certain orientations show high birefringence in cross- polarised light. Etymology: In honour of Dr. M.-P. AUBRY (Lyon, France), author of the "Handbook of Cenozoic Calcareous Nannoplankton". Extra details from original publication Remarks. - Aubrysphaera differs from other holococcolithid genera by its typical dome-shaped outline and by its hollow construction, which, in certain orientations, show high birefringence under crossed nicols. There is a certain similarity of shape and construction between this genus and Trochoaster KLUMPP, 1953. The latter, however never exhibits birefringence under crossed nicols (see AUBRY, 1988,p. IV). This difference in optical behaviour cannot be due to secondary calcification because representatives of Trochoaster which show no birefringence (e.g. T. operosus) are also found in the same samples and slides. Aubrysphaera also seems to be related to the genus Dactylethra GARTNER, 1969. The type species of this monospecific genus D. punctulata GARTNER, 1969, however, has a solid construction with a completely enclosed centre which is filled with calcite (see GARTNER & BUKRY, 1969, p. 1219). It also seems to be formed of several crystals of calcite, which act differently in cross-polarised light, some of them showing maximum and others minimum birefringence.
Only one species is known, the type species Aubrysphaera deconinckii. It is recorded from various exposures and boreholes in the Ypresian of the Belgian Basin.
References:
Steurbaut, E. (1990). Ypresian calcareous nannoplankton biostratigraphy and palaeogeography of the Belgian Basin. Bulletin de la Société Belge de Géologie. 97(1988): 251-285. gs
Aubrysphaera: Catalog entry compiled by Richard Howe. Viewed: 9-10-2024
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