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Discoaster surculus

Edited by Lyndsey on Thu, 10/03/2011 - 13:23

Discoaster surculus Martini and Bramlette, 1963

Description: 6-rayed discoaster with trifurcate ray-tips. Similar to D. variabilis but with proximal ray tip extensions giving trifurcate appearance to ray tips. Usually slightly concavo-convex with well-developed central area and showing strong differentiation of proximal and distal surface.

Remarks: In LM through focusing is often needed to see the ray tip extensions. D. surculus, like D. variabilis, varies considerably in size, and in ray tip morphology. It has not, however, been subdivided.

Original description:

Discoaster surculus 090232.jpgDiscoaster surculus 090233.jpg

7-22surculus.JPG 7-21surculus.JPGDsurc190-26NN16.JPGDsurc263-09NN11.JPG

Geological Time Data
Geological Time Periods: 
NN11a
NN17
Biblio Reference: 
Young, JR.  1998.  Neogene. Calcareous nannofossil biostratigraphy. :225-265.
Notes on occurrence information: 

Common from NN11A to top NN17. Its last occurrence is used as a datum, the first occurrence is not since it is rather gradational.

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