Cribrocentrum

Coccolithus foveolatus Reinhardt, 1966a

Elliptical to circular reticulofenestrid has a single cycle tube, distal and proximal shields, and a central area spanned by a birefringent central mesh characteristic for Cribrocentrum. The entire coccolith is completely birefringent in polarised light. The central area may have fine or larger pores or both and a central field.

Elliptical Groups

Cribrocentrum ornatum Group

with a single cycle of large pores & non-porous central field

• Cribrocentrum ornatum (Müller, 1970b) Varol, n. comb.; 5.0 - 10.0µm
• Cribrocentrum pectinatum (Roth, 1970) Varol, n. comb.; <5.0µm

Cribrocentrum foveolatum Group

with a single cycle of large pores & perforated central field

• Cribrocentrum retiformis (Reinhardt, 1966a) Varol, n. sp.; 5.0 - 10.0µm
• Cribrocentrum foveolatum (Reinhardt, 1966a) Perch-Nielsen, 1971c; <5.0µm

Cribrocentrum gartneri Group

with numerous random perforation

• Cribrocentrum gartneri (Roth & Hay in Hay et al. 1967) Varol n. comb.; 5.0 - 10.0µm

Cribrocentrum oamaruensis Group

without numerous random perforation

• Cribrocentrum oamaruensis (Deflandre in Deflandre & Fert 1954) Varol, n. comb.; >13.0µm
• Cribrocentrum lockeri (Muller, 1970b) Varol, n. comb. ; 10.0 - 13.0µm
• Cribrocentrum antillarum (Black,1967) Varol, n. comb.; 5.0 - 10.0µm
• Cribrocentrum macmillanii (Dunkley Jones, Bown & Pearson, 2009) Varol, n. sp.; <5.0µm

Circular Group

Cribrocentrum reticulatum Group

• Cribrocentrum isabellae Catanzariti et al. in Fornaciari et al., 2010; >12.0µm
• Cribrocentrum reticulatum (Gartner & Smith, 1967) Perch-Nielsen, 1971c; 5.0 - 12.0µm
• Cribrocentrum artuziae (Varol, 1989) Varol, n. comb. ; <5.0µm

Cribrocentrum species are identified based on their overall size, shape, width of their pelaga, the presence or absence of the pores and their size and the presence or absence of porous or non-porous central field. Cribrocentrum differs from Reticulofenestra Hay, Mohler & Wade, 1966 by having a permanent birefringent central mesh. It is distinguished from Obturolithus Varol in prep. by lacking a distal plug.

Deflandre, G., Fert, C., 1954. Observations sur les coccolithophoridés actuels et fossiles en microscopie ordinaire et électronique. Annales de Paléontologie 40, 115-176.

Dunkley Jones, T., Bown, P. R., Pearson, P., 2009. Exceptionally well preserved upper Eocene to lower Oligocene calcareous nannofossils (Prymnesiophycidae) from the Pande Formation (Kilwa Group), Tanzania. Journal of Systematic Palaeontology 7(4), 359-411.

Fornaciari, E., Agnini, C., Catanzariti, R., Rio, D., Bolla, E. M., Valvasoni, E., 2010. Mid- Latitude calcareous nannofossil biostratigraphy and biochronology across the middle to late Eocene transition. Stratigraphy 7(4), 229-264.

Gartner, S., Smith, L. A. 1967. Coccoliths and related calcareous nannofossils from the Yazoo Formation (Jackson, Late Eocene) of Louisiana. University of Kansas Paleontological Contributions, Papers 20, 1-7.

Hay, W. W., Mohler, H. P., Roth, P. H., Schmidt, R. R., Boudreaux, J. E., 1967. Calcareous nannoplankton zonation of the Cenozoic of the Gulf Coast and Caribbean-Antillean area, and transoceanic correlation. - Transactions of the Gulf-Coast Association of Geological Societies 17, 428-480.

Hay, W. W., Mohler, H. P., Wade, M. E., 1966. Calcareous nannofossils from Nal'chik (northwest Caucasus). Eclogae Geologicae Helvetiae 59, 379-399.

Müller, C., 1970b. Nannoplankton-Zonen der Unteren-Meeresmolasse Bayerns. Geologica Bavarica 63, 107-118.

Perch-Nielsen, K., 1971c. Elektronenmikroskopische untersuchungen an Coccolithen und verwandten Formen aus dem Eozan von Danemark. Biologiske Skrifter, Kongelige Danske Videnskabernes Selskab. 18(3), 1-76.

Reinhardt, P., 1966a. Fossile Vertreter coronoider und styloider Coccolithen (Family Coccolithaceae Poche 1913). Monatsberichte der Deutschen Akademie der Wissenschaften zu Berlin 8, 513-524.

Roth, P. H., 1970. Oligocene calcareous nannoplankton biostratigraphy. Eclogae Geologicae Helvetiae 63, 799-881.

Black, M., 1967. New names for some coccolith taxa. - Proceedings of the Geological Society of London 1640, 139-145.

Varol, O., 1989b. Eocene calcareous nannofossils from Sile (northwest Turkey). Revista Española de Micropaleontología 21, 273-320.