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
Nannotax3 - ntax_Farinacci - Caycedoae.pdfCurrent identification:
Compiled data
Original Description
Description: Circular-subcircular heliolith has one disc and a column. In the side-view, the disc appears slightly concave, and depression is present on the proximal side. The column displays variable height and possesses a narrow central canal. The species of this genus are regularly observed in plan-view and side-view because they contain a high column that allows for naturally settling in both views. The terminology of Caycedoae is presented in Fig. 10. The species of this genus are often erroneously assigned to Bomolithus. The holotype of Bomolithus elegans (type species of Bomolithus) is an SEM micrograph (Roth, 1973; Pl. 15, figs. 1) revealing two different discs of equal diameter and a high column. The mobile mount technique used in this study indicates that Bomolithus elegans possesses birefringent discs, proving that the paratype of Bomolithus elegans (Roth, 1973; Pl. 15, figs. 6a–d) is an entirely different species. Subsequently, specimens comparable to the paratype (but not to the holotype) have been erroneously placed into Bomolithus elegans by many authors, including Perch-Nielsen (1977, 1985), Varol (1989) and Bown (2010, 2016). The mobile mount technique demonstrates that the forms comprising a non-birefringent disc and a birefringent column are very different from Bomolithus. These forms are now assigned to the new genus Caycedoae.
Optical properties: The disc and column are birefringent in the side-view. In cross polarized light, the distal side shows a dextrogyre-type extinction pattern (e.g. Pl. 26, figs.10, 14), whereas the proximal side is characterized by a laevogyre-type extinction pattern (e.g. Pl. 26, figs. 11, 15). When using the gypsum plate, the distal view will show the blue regions corresponding to the horizontal axis, while the proximal view will show the blue sectors corresponding to the vertical axis.
Etymology:
Extra details from original publication
Bowman, A. R. & Varol, O. (2021). A taxonomic revision of Heliolithaceae—Applications in resolving the problematic calcareous nannofossil biostratigraphy of the Paleocene. In, Montenari, M. (ed.) Stratigraphy & Timescales 6. Academic Press (2): 43-223. gsReferences:
 |
Caycedoae: Catalog entry compiled by <% compiler %>. Viewed: 12-10-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=55218 Go to Archive.is to create a permanent copy of this page - citation notes |
 |