Kennett & Srinivasan (1983):
Ss. disjuncta differs morphologically from Globigerina (Zeaglobigerina) woodi in exhibiting a much more thickened test, although the surface character in Ss. disjuncta
still lacks the highly thickened glossy appearance typical of Sphaeroidinellopsis. Specimens of Ss. disjuncta exhibiting three chambers in the final whorl closely resemble Globigerina (Zeaglobigerina) connecta Jenkins. The surface ultrastructure in Ss. disjuncta is intermediate in character between the distinct reticulate pattern of Gg. (Zg.) woodi and the smooth, glossy cortex of Sphaeroidinellopsis.
Because the test wall in Ss. disjuncta shows such a strong tendency to thicken, we prefer to assign this form to Sphaeroidinellopsis rather than Globigerina (Zeaglobigerina).
Bolli & Saunders (1985):
S. disjuncta is the stratigraphically earliest species of the lineage. In the early part of its range specimens are smaller compared with later ones, mostly with 3 chambers in the last whorl, occasionally with 4. The average test size increases gradually during the Globorotalia fohsi zones; 4-chambered specimens become more frequent and occasionally even 5 chambered forms appear. The shape of the chambers is subglobular, the last chambers have a tendency to become radially somewhat elongated Sutural incisions in 3-chambered forms are slight; they are deeper in 4-chambered specimens. The aperture of the last chamber leading into the umbilicus is often protected by a distinct rounded lip, particularly in the larger specimens. Higher in the lineage, beginning with S. multiloba, the rounded lips gradually take on the flange like shape typical for the forms in the later part of the lineage (S. seminulina, S. sphaeroides). The walls are massive and distinctly pitted. Increased cortex formation that eventually leads to the smooth glassy surface characterizing S. multiloba gradually develops through transitional forms from S. disjuncta.
Chaisson & Leckie (1993):
Similar species: Sphaeroidineüopsis disjuncta is gradational with both S.
seminulina and S. kochii (e.g., see Plate 10, Fig. 17). It is distinquished from
these taxa by its coarsely cancellate wall and only weakly developed cortex.
S. disjuncta is also gradational with Globigerina druryi, from which it is
distinguished by its distinctly thickened test wall (e.g., see Plate 10, Fig. 15). |
Finlay,H.J. (1940):
New Zealand Foraminifera; key species in stratigraphy . Transactions of the Royal Society of New Zealand Vol. 69
Keijzer,F.G. (1945):
Outline of the geology of the eastern part of the province of Oriente, Cuba (E. of 76° W.L.), with notes on the geology of other parts of the island.. , Geographische en Geologische Mededelingen, Physiographisch-Geoloogische Reeks Ser II Vol. 6 p. 1-239
Kennett,J. and Srinivasan,M.S. (1983):
Neogene Planktonic Foraminifera - A Phylogenetic Atlas.
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
Chaisson,W.P. and Leckie,R.M. (1993):
High-Resolution Planktonic Foraminifer Biostratigraphy of Site 806, Ontong Java Plateau (Western Equatorial Pacific).
In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 130 Eds: Berger, W.H.Kroenke, L.W..Mayer, L.A..et al. p. 137-178
Chaisson,W.P. and d'Hondt,S.L. (2000):
Neogene planktonic foraminifer biostratigraphy at Site 999, Western Caribbean Sea.
In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 165 Eds: Leckie, R.M.Sigurdsson, H.Acton, G.D.Draper, G. p. 19-56
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