Globigerinoides obliquus extremus Bolli & Bermudez 1965 from: Vincent, E.Toumarkine, M. (1990): Neogene planktonic foraminifers from the Western Tropical Indian Ocean, Leg 115. In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 115 Eds: Duncan, R.A..Backman, J.Peterson, L.C. p. 795-836 . |
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Subspecies Globigerinoides obliquus extremus Bolli & Bermudez 1965 |
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Discussion / Comments: |
Bolli & Saunders (1985):
G, obliquus obliquus gave rise to the subspecies extremus within the Globorotalia humerosa Zone, the last chamber becoming still more compressed laterally and, as a result, more asymmetrical. The earlier chambers, in particular those forming the last whorl, may also be compressed laterally and be of irregular shape, though less so than the final chamber. The subspecies extremus ranges from the Globorotalia humerosa Zone into the lower part of the Globorotalia exilis Subzone. However, it has frequently been reported as occurring also higher stratigraphically. This is probably due to a confusion with G. elongatus (Fig. 20.4), present in the Pliocene to Holocene and, like extremus, possessing a similar asymmetrically depressed last chamber. The distinction between the two is best made by observing the position of the primary aperture which in elongatus (as in G. ruber) is symmetrical above the suture between the two earlier chambers, but in extremus is asymmetrical. |
Synonym list: |
Bolli & Saunders (1985):
Vincent & Toumarkine (1990):
Quilty (1976):
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Was used in synonym list of: |
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References: |
Bolli,H.M. and Bermudez,P.J. (1965): Zonation based on planktonic foraminifers of Middle Miocene to Pliocene warm-water sediments. . Asoc. Venezolana Geol., Miner. Petrol. Bol. Inf. Vol. 8
Quilty,P.G.. (1976): Planctonic foraminifera DSDP Leg 34- Nazca Plata . DSDP initial reports Vol. 34
Bolli,H.M. and Saunders,J.B. (1985): Oligocene to Holocene low latitude planktic foraminifers. In: Plankton Stratigraphy Eds: Bolli, H.M.Saunders, J.B. p. 155-262
Vincent,E. and Toumarkine,M. (1990): Neogene planktonic foraminifers from the Western Tropical Indian Ocean, Leg 115. In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 115 Eds: Duncan, R.A..Backman, J.Peterson, L.C. p. 795-836
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