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.
Taxa are sorted alphabetically for simple browsing, or you can use search boxes at the top & bottom of the page
Original Description Diagnosis: This family is characterised by tubular calcareous nannofossils with a double-storey, unicyclic wall structure. Each storey consists of numerous segments strongly imbricated in a sinistral orientation. The two walls often differ in height, and at their intersection, a disjunct amedian diaphragm extends. The outer surface is commonly ornamented with both lateral and longitudinal features. Extra details from original publication Optical Properties: Perchnielsenaceae exhibit parallel (straight) extinction with length-fast (-) elongation in the plan view and length-slow (+) elongation in the side view. First-order yellow to second-order blue interference colours are observed, reflecting the significant height and width (retardation colours). This species in this family can settle randomly in either plan or side view due to its similar height-to-width ratio. Editors' Notes It is not clear why the name was given as Perchnielsenaceae instead of Perchnielsenellaceae, this maty be a correctable mistake.
References:
Varol, O. (2025). A practical guide to optical studies of calcareous nannofossils. Grzybowski Foundation Special Publication. 29: 1-222. gs
Perchnielsenaceae: Catalog entry compiled by Jeremy Young. Viewed: 8-2-2026
Farinacci & Howe catalog - Perchnielsenaceae.pdf
