Sphaeroidinellopsis hancocki Bandy 1975 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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Species Sphaeroidinellopsis hancocki Bandy 1975 |
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Discussion / Comments: |
Bolli & Saunders (1985):
In this species are placed specimens of the S. seminulina plexus with 4 1/2, 5, and occasionally 6 or even 7 chambers in the last whorl, instead of 3 or 4 in S. seminulina. Except for the number of chambers there are no other criteria that distinguish the two species. S. hancocki is maintained because of its restriction to the Early Pliocene Globorotalia margaritae margaritae Subzone, making it an important marker. The final chamber, occasionally also the penultimate, may as in the 4-chambered S. seminulina display a sacculiferid shape. In specimens with a distinct cortex the umbilical area is bordered by flanges; in specimens without, often by thick spines partially extending over the umbilical area. As in S. seminulina all stages from non corticated to fully corticated specimens exist. S. hancocki has appeared in the literature under a number of names, but always reported from the Early Pliocene. Examples are: S. seminulina (Parker, 1967), S. seminulina A (Bolli, 1970), S. seminulina paenedehiscens (Salvatorini & Cita, 1979). The holotype drawings of Globigerina kochi, Caudri, 1934, from Java, indicate that this species is synonymous with S. hancocki. However, the original type deposited at the Museum of Natural History in Basic is now represented only by fragments due to the growth of gypsum crystals, and thus a reliable identification is no longer possible. An indication that the original type of G. kochi, is of Early Pliocene age, as is S. hancocki, is its co occurrence with the holotype of Globorotalia tumida flexuosa, a species known to occur in Java also in the Early Pliocene (Bolli, 1966b). |
Synonym list: |
Bolli & Saunders (1985):
? 1934 Globigerina kochi Caudri. - Caudri : pl. 144 (in Koch, 1923-24, p. 355, table p. 351, figs. 8a-b)
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Was used in synonym list of: |
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References: |
Caudri,C.M.B. (1934): Tertiary Deposits of Soemba. p. 1-223
Bolli,H.M. (1970): foraminifera of Sites 23-31, Leg 4 . Initial Rep. Deep Sea drill. Proj. Vol. 4 p. 577-643
Bandy,0.L.. (1975): Messinian evaporite deposition and the Miocene/Pliocene boundary, Pasquasia Capodarso sections, Sicily. In: Late Neogene Epoch Boundaries, Micropaleontology, Special Publication Vol. 1 Eds: Saito, T.Burkle, L.H.. p. 49-63
Ujiié,H.. (1976): Prosphaeroidinella, n.gen.: Probable ancestral taxon of Sphaeroidinellopsis (foraminifera) . Bull. natl. Sci. Mus. Tokyo, ser. C (Geology & Paleontology) Vol. 2(1) p. 9-26
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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