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Discoaster berggrenii

Edited by Jeremy Young on Wed, 28/09/2011 - 21:43

Discoaster berggrenii Bukry, 1971

Description: Intermediate form between D. bergennii and D. quinqueramus with central-area 1-2x free ray length.

Remarks: As observed by Muller (1974) and Theodoridis (1984) D. berggrenii grades into D. quinqueramus, and is probably not a separate species. It is, however, only common in the lower part of the range of D. quinqueramus; and discrimination of it is easy.
See also separate page on this plexus.

 

Original description:

Discoaster berggrenii 010410.jpgDiscoaster berggrenii 010411.jpg

8-11berggrenii.JPG 8-12berggrenii.JPG

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

Comments

Wed, 28/09/2011 - 14:29 — mstyzen
mstyzen's picture

Discoaster quinqueramus/berggrenii plexus

I posted a document with some sketches from the original Gulf Coast Taxonomic Equivalency Project of this group in the forum.

Thu, 03/03/2011 - 14:14 — mstyzen
mstyzen's picture

Discoaster berggrenii extensus

A few years ago Wuchang Wei erected a new subspecies, Discoaster berggrenii extensus for forms in which the star in the central area extends beyond the central area. This taxon is used pretty universally in the GOM as a Late Miocene under the name of "Discoaster C". I think, however that the name D. berggrenii extensus should be supressed. I have started to see reports from various sources that list this taxon simply as "Discoaster extensus" which, of course, is something else alltogether. In my opinion, since this form is used as an index fossil by such a lirge number of workers, that we should consider making it a seperate species.

Sat, 05/03/2011 - 20:20 — Jeremy Young
Jeremy Young's picture

reference?

do you have the reference for the original description? It would be good to add it to the system.
Jeremy

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