Nannotax3 - ntax_cenozoic - Discoaster berggrenii

Citation: Discoaster berggrenii Bukry, 1971

Variants: Discoaster berggrenii ssp. extensus Wei 2003 variant in which the sutural ridges protrude beyond the edges of the central disk.

Taxonomic discussion: 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.

Distinguishing features:
Parent taxon (D. quinqueramus group): Symmetric typically 5-rayed, late Miocene discoasters; rays curved proximally, without bifurcations; well-developed distal star and usually proximal boss
This taxon: prominent central structures and short free rays, stem-ridges confined to central area

Geological Range:
Notes: D. bergenii, D. bergrennii and D. quinqueramus apparently form an anagenetic lineage, with central area size deceasing and free ray length increasing. Distinguishing them is useful for determining position within the early part of zone NN11.
Last occurrence (top): near top of NN11 zone (90% up, 5.9Ma, in Messinian stage). Data source: Young 1998 (fig. 8.4)
First occurrence (base): at base of NN11 zone (0% up, 8.3Ma, in Tortonian stage). Data source: zonal marker, with D. quinqueramus (see e.g. Young 1998)

References:

Bergen, J. A. (1984). Calcareous nannoplankton from Deep Sea Drilling Project Leg 78A: evidence for imbricate underthrusting at the Lesser Antillian active margin. Initial Reports of the Deep Sea Drilling Project. 78A: 411-445. gs

Blair, S. A., Bergen, J. A., de Kaenel, E., Browning, E. & Boesiger, T. M. (2017). Upper Miocene-Lower Pliocene taxonomy and stratigraphy in the circum North Atlantic Basin: radiation and extinction of Amauroliths, Ceratoliths and the D. quinqueramus lineage. Journal of Nannoplankton Research. 37(2-3): 113-144. gs O

Bukry, D. (1971a). Discoaster evolutionary trends. Micropaleontology. 17: 43-52. gs

Müller, C. (1974). Calcareous nannoplankton, Leg 25 (Western Indian Ocean). Initial Reports of the Deep Sea Drilling Project. 25: 579-633. gs

Perch-Nielsen, K. (1972). Remarks on Late Cretaceous to Pleistocene coccoliths from the North Atlantic. Initial Reports of the Deep Sea Drilling Project. 12: 1003-1069. gs

Salomon, R. (1999). The Calcite Palace. Website - https://ina.tmsoc.org/galleries/CalcitePalace/index.htm. -. gs

Theodoridis, S. (1984). Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. Utrecht Micropaleontological Bulletin. 32: 1-271. gs O

Wei, W. (2003). Upper Miocene nannofossil bistratigraphy and taxonomy of Exxon core CH30-43-2 from the Gulf of Mexico. Journal of Nannoplankton Research. 25(1): 17-23. gs

Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 225-265. gs

Comments (5)

Mike Styzen(US)

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.

28 September 2011 00:00

Magdy(India)

Mike...
Thanks for producing sketches for the Discoaster quinqueramus/berggrenii plexus. I found it very useful.
Some how I lost the original copy. Could you tell where you have posted this document, hopefully I will be able to download it.
Regards
Magdy

15 April 2016 16:43

Jeremy Young(UK)

Hi Magdy
A copy of the diagram is here. GECP chart - and it is linked to from the D. quinqueramus group page. I have slightly cleaned up Mike's original diagram and added the coloured columns on the right but otherwise it is his figure."""

15 April 2016 21:44

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."""

3 March 2011 00:00

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

5 March 2011 00:00

Discoaster berggrenii

References:

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Comments (5)