Globorotalia crassaformis viola Blow 1969 from: Bolli, H.M.Saunders, J.B. (1985): Oligocene to Holocene low latitude planktic foraminifers. In: Plankton Stratigraphy Eds: Bolli, H.M.Saunders, J.B. p. 155-262 | . |
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Subspecies Globorotalia crassaformis viola Blow 1969 |
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| Discussion / Comments: |
Bolli & Saunders (1985):
Intermediate forms indicate that the subspecies viola is closely related to the G. crassaformis plexus. In Caribbean DSDP sections (Legs 4, 15) it branched off from crassaformis in the upper part of the Early Pliocene through gradual acquisition of a peripheral keel. Typical viola possess a complete peripheral keel. In side view they are more angular compared with crassaformis and not as highly conical. Intercameral sutures on the spiral side may also be limbate in contrast to crassaformis. A particular feature is that early parts of the test remain distinctly pustulose. Intermediate forms between non carinate crassaformis and wholly carinate viola forms, also still with the pustulose surface, occur in several Pliocene Pleistocene Caribbean DSDP sections; a close relation is therefore regarded as established between the subspecies crassaformis and viola. |
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Bolli & Saunders (1985):
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| References: |
Blow,W.H. (1969):
Late middle Eocene to Recent planktonic foraminiferal biostratigraphy.
In: Proceedings of the First International Conference on Planktonic Microfossils, Geneva 1967 Vol. 1 Eds: Bronnimann, P.Renz, H.H. p. 199-422
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
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