Nannotax3 - ntax_cenozoic - Calcidiscus leptoporus subsp. quadriperforatus

Citation: Calcidiscus leptoporus subsp. quadriperforatus (Kamptner 1937) Geisen et al., 2002

Basionym: Syracosphaera quadriperforata Kamptner 1937

Synonyms:

Calcidiscus quadriperforatus (Kamptner 1937) Quinn & Geisen, in Saez et al. 2003
Calcidiscus leptoporus type B Kleijne 1993
Calcidiscus uniforatus Kamptner (1963) [isolated distal shield]

Taxonomic discussion: Separation of this morphotype from the rest of modern Calcidiscus was initially suggested by Kleijne (1993) on morphological grounds and has been strongly supported by culture observations, life-cycle studies (it produces distinctive holococcoliths) and molecular genetics (see summary in Geisen et al. 2004). The epithet quadriperforatus comes from the holococcolith stage. Saez et al. (2003) recommended separating the form as species (C. quadriperforatus), we prefer to use it as a sub-species since it is frequently impossible to seperate the two forms.

Distinguishing features:
Parent taxon (Calcidiscus leptoporus): Species of Calcidiscus producing circular to sub-circular coccoliths with, closed central-area.
This taxon: liths 7-9µm, circular, sutures obscured around central area

Coccoliths large sized, 7-11 µm, with 20-35 elements; distal shield sutures smoothly curved on shield then obscured around crest of tube.

HOL = open tube with internal septa (formerly called Syracolithus quadriperforatus). Association is based on a single, unambiguous, combination coccosphere (Geisen et al. 2002, and illustrated here).

Geological Range:
Notes: Fossil range not determined
Last occurrence (top): Extant. Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within Pliocene Epoch (2.59-5.33Ma, base in Zanclean stage). Data source: [JRY rough estimate]

References:

Cros, L. & Fortuño, J. -M. (2002). Atlas of northwestern Mediterranean coccolithophores. Scientia Marina. 66: 1-186. gs

Geisen, M., Billard, C., Broerse, A. T. C., Cros, L., Probert, I. & Young, J. R. (2002a). Life-cycle associations involving pairs of holococcolithophorid species: intraspecific variation or cryptic speciation? European Journal of Phycology. 37: 531-550. gs

Geisen, M. et al. (2004b). Species level variation in coccolithophores. In, Thierstein, H. R. & Young, J. R. (eds) Coccolithophores - From molecular processes to global impact. Springer, Berlin 327-366. gs

Kamptner, E. (1937). Neue und bemerkenswerte Coccolithineen aus dem Mittelmeer. Archiv für Protistenkunde. 89: 279-316. gs

Kleijne, A. (1993b). Morphology, Taxonomy and distribution of extant coccolithophorids (Calcareous nannoplankton). PhD Thesis, Vrije Universiteit Amsterdam. 1-321. gs

Quinn, P., Sáez, A. G., Baumann, K. -H., Steel, B. A., Sprengel, C. & Medlin, L. K. (2004). Coccolithophorid biodiversity: Evidence from the cosmopolitan species Calcidiscus leptoporus. In, Theirstein, H. R. & Young J. R. (eds) Coccolithophores - From molecular processes to global impact. Springer, Berlin 299-326. gs

Sáez, A. G., Probert, I., Geisen, M., Quinn, P., Young, J. R. & Medlin, L. K. (2003). Pseudo-cryptic speciation in coccolithophores. Proceedings of the National Academy of Sciences, USA. 100(12): 7163-7168. gs

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. S1: 1-132. gs

Calcidiscus leptoporus subsp. quadriperforatus

References:

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