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Umbilicosphaera foliosa

Edited by Lyndsey on Thu, 10/03/2011 - 11:13

Umbilicosphaera foliosa (Kamptner 1963, ex Kleijne 1993) Geisen in Sáez et al. 2003. [Cycloplacolithus]

Description: Coccosphere compact. Coccoliths circular with narrow central opening narrow; sutures on distal shield strongly kinked. Proximal shield bicyclic, concave, smaller than distal shield. A few hook-shaped protrusions are often present in the central opening.

Remarks: This taxon was regarded as a variety of U. sibogae (U. sibogae var. foliosa) but there are strong morphological differences between U. sibogae and U. foliosa and cultures of the two species maintain their respective morphologies (Geisen et al. 2004). Molecular genetic data indicates that they are sibling species and suggests a divergence in the Miocene (Sáez et al. 2003).

 

Original description:

Cat040234 copy.jpgCat040235 copy.jpg

5-3sibogae_foliosa.JPG 5-4sibogae_foliosa.JPGUmbfol201 (471-0) 21NN14-15.JPGUmbilicosphaeraF.JPGUmbilicosphaeraC.JPGUmbilicosphaeraE.JPGU_foliosa_185-41.JPGU_foliosa_114-51.JPG

Geological Time Data
Geological Time Periods: 
NN21
NN16
Biblio Reference: 
Young, JR.  1998.  Neogene. Calcareous nannofossil biostratigraphy. :225-265.
Notes on occurrence information: 

Probably evolves from U. jafari in the Pliocene. SEM above, from the Early Miocene is a rather clear U.foliosa specimen from a sample set also with unambiguous U. jafari and U. rotula.

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