Globigerina cariacoensis Rögl & Bolli 1973 from: Iaccarino, S. (1985): Mediterranean Miocene and Pliocene planktic foraminifera. In: Plankton stratigraphy Eds: Bolli, H.M.Saunders, J.B.Perch-Nielsen, K. p. 283-314 . |
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Species Globigerina cariacoensis Rögl & Bolli 1973 |
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Discussion / Comments: |
Iaccarino (1985):
The major morphological features of this species are the high to very high troehospire, fairly lobate equatorial periphery, loosely arranged globular chambers increasing regularly in size except for the last one which may be tilted over the umbilicus, a large umbilicus nearly quadrangular in outline, a wide and low arched aperture without lip and a transparent and delicate wall densely and regularly covered by pores.
G. cariacoensis differs from G. megastoma (see lectotype description in Banner & Blow, 1960) only in the wider aperture without lip and in the greater number of chambers (13-14 against 11). The other features such as the height of the troehospire, the loose arrangement of the chambers, the shape of the last chamber and the structure of the wall are closely related.
The specimens of G. cariacoensis with more elongated chambers suggest a relationship with G. bermudezi, which differs in the much lower troehospire and in the final chamber being distinctly elongated in a spiro umbilical direction which gives rise to a more extraumbilical position of the aperture. This species, described from the Caribbean, has also been recorded recently from the Mediterranean (Selli et al., 1977; Colalongo & Sartoni, 1977; Colalongo & Sartoni, 1979). However, the specimens from this area do not show the typical wall structure of the Caribbean forms. The appearance of G. cariacoensis is inferred to be an important stratigraphic event in recognizing the Plio Pleistocene boundary. Poore & Berggren (1975) have already tentatively utilized this event for this purpose. In fact, the first occurrence of G. cariacoensis is the event which most closely approximates the Plio Pleistocene boundary in the Vrica stratotype section in Calabria.
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Systematics: |
1 Superregnum Eukaryota
Regnum Protoctista
Phylum Ciliophora
Subphylum Postciliodesmatophora
Ordo Globigerinida
Superfamilia Globigerinaceae
Superfamilia Nonionacea
Familia Globigerinidae
Genus Globigerina
Species Globigerina cariacoensis
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Synonym list: |
Iaccarino (1985):
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Stratigraphy - absolute ages: |
LAD: 1.77 ± 0 [Ma], Berggren et al. (1995) Mediterranean
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References: |
Rögl,F. and Bolli,H.M. (1973): Holocene to Pleistocene planktonic foraminifera of Leg 15, Site 147 (Cariaco Basin (Trench), Caribbean Sea) and their climatic interpretation. In: Initial Reports of the Deep Sea Drilling Project Vol. 15 Eds: Edgar, N.T. p. 553-616
Iaccarino,S. (1985): Mediterranean Miocene and Pliocene planktic foraminifera. In: Plankton stratigraphy Eds: Bolli, H.M.Saunders, J.B.Perch-Nielsen, K. p. 283-314
Berggren,W.A.; Hilgen,F.J.; Langereis,C.G.; Kent,D.V.; Obradovich,J.D.; Raffi,I.; Raymo,M.E. and Shackleton,N.J. (1995): Late Neogene chronology: New perspectives in high-resolution stratigraphy . Geological Society of America Bulletin Vol. 107(11)
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