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Helicosphaera sellii

Edited by Jeremy Young on Wed, 09/03/2011 - 18:31

Helicosphaera sellii (Bukry and Bramlette, 1969) Jafar and Martini, 1975 [Helicopontosphaera]

Description: Like H. carteri but pores large.

Remarks:

Range: NN12 to 19. Last occurrence has been used in some zonatons but is rather diachronous

Original description:

Helicopontosphaera sellii 080439.jpgHelicopontosphaera sellii 080440.jpg

Variant: H. omanica Sato, Kameo and Takayama, 1991 - bar missing, ? dissolved. Also similar to H. neogranulata.

Geological Time Data
Geological Time Periods: 
NN19
NN12
Biblio Reference: 
Young, JR.  1998.  Neogene. Calcareous nannofossil biostratigraphy. :225-265.

Comments

Wed, 09/03/2011 - 20:00 — mstyzen
mstyzen's picture

Stratigraphically

This species is widely used as a marker in the GOM. Unfortunately I think most workers would not pick it on a specimen resembling the holotype (figures 3and 4 in the original description). Most of us would wait till we saw one with the larger squared-off pores such as illustrated in the specimen illustrated in figures 5 and 6 before making the call.

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