| Daughter taxa: (blue => in age window 0-800Ma) | Granddaughter taxa | ||||
 |  |  |  | Calyptrosphaera sphaeroidea HET Coccoliths elliptical narrow-rimmed placoliths with plate formed from numerous small elements in central area | |
 |  |  |  | Navilithus Coccoliths narrow-rimmed placoliths with robust central spine; CFCs with tall, sail-like, spines | |
 |  |  |  | Placorhombus Coccoliths rhombic narrow-rimmed placoliths with four plates in central area | |
 |  |  |  | Tetralithoides Coccoliths elliptical narrow-rimmed placoliths with four plates in central area | |
 |  |  |  | Turrilithus Coccoliths elliptical narrow-rimmed placoliths with quadrate tower-like central structure | |
Taxonomy:
Distinguishing features: Diverse group of coccoliths with narow placolith rims and variable central strcutrues, usually showing four-fold symmetry
Farinacci & Howe catalog pages: narrow rimmed placoliths [no catalog entry yet]
Morphology: Rims in these genera appear to reformed of a single cycle of non-imbricate elements with radial sutures. Central area structures are highly variable but disjunct and usually with four-fold symmetry
Size: Coccoliths very small 0.5-2.5 mm) except in Tetralithoides (4-7.5 µm)
Ecology & Biogeography: Deep photic
Biology & life-cycles: Calyptrosphaera sphaeroidea has both holococcolith and heterococcolith phases and has been cultured (Noël et al. 2004), the other taxa are so far only known from the heterococcolith phase and have not been cultured.
Phylogenetic relations: Calyptrosphaera sphaeroidea falls within the Coccolithales clade in molecular genetic analyses (Fujiwara et al., 2001; Saez et al., 2004, Young et al. 2014 Cryptogamie)
| Tags | LITHS: |
| Metrics | Lith size: 0.5->7.5µm; |
Geological Range:
Notes: Only Tetralithoides has a documented fossil record, extending back to the Early Miocene (Theodoridis, 1984; Young, 1998).
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): in upper part of Thanetian Stage (62% up, 57.2Ma, in Thanetian stage). Data source: Total of range of species in this database
Plot of occurrence data:
Fujiwara, S., Tsuzuki, M., Kawachi, M., Minaka, N. & Inouye, I. (2001). Molecular phylogeny of the haptophyta based on the rbcL gene and sequence variation in the spacer region of the RUBISCO operon. Journal of Phycology. 37: 121-129. gs Noël, M. -H., Kawachi, M. & Inouye, I. (2004). Induced dimorphic life cycle of a coccolithophorid, Calyptrosphaera sphaeroidea. Journal of Phycology. 40(1): 112-129. gs Sáez, A. G., Probert, I., Young, J. R., Edvardsen, B., Wenche, E. & Medlin, L. K. (2004). A review of the phylogeny of the Haptophyta. In, Thierstein, H. R. & Young, J. R. (eds) Coccolithophores - from molecular processes to global impact. Springer, Berlin 251-270. gs V O Theodoridis, S. (1984). Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. Utrecht Micropaleontological Bulletin. 32: 1-271. gs V O Young, J. R. & Andruleit, H. (2006). Navilithus altivelum: a remarkable new genus and species of deep photic coccolithophores. Journal of Micropalaeontology. 25(2): 141-152. gs V O Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 225-265. gs V O Young, J. R., Geisen, M., Cros, L., Kleijne, A., Probert, I. & Ostergaard, J. B. (2003). A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research, Special Issue. 1: 1-132. gs V O Young, J. R., Liu, H., Probert, I., Aris-Brosou, S. & de Vargas, C. (2014b). Morphospecies versus phylospecies concepts for evaluating phytoplankton diversity: The Case of the Coccolithophores. Cryptogamie Algologie. 35(4): 353-377. gsReferences:
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narrow rimmed placoliths compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 22-1-2021
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