Distinguishing features: Parent taxon (Sphaeroidinellopsis): trochospiral test, globular chambers, and a heavy, smooth, shiny cortex This taxon: Like S. seminulina but somewhat compressed trochospiral test with >3 chambers in final whorl.
NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They are being edited as the site is developed and comments on them are especially welcome.
Aperture: Umbilical large irregular opening with a thickened lip [Aze 2011, based on Kennett & Srinivasan 1983]
Morphology: Test large, a compressed low trochospiral, equatorial periphery lobulate, axial periphery rounded; chambers subspherical to oval, 4 to 5 in the final whorl, sutures distinct, slightly depressed; surface smooth, very coarsely perforate, unthickened specimens distinctly cancellate (PI. 52, Fig. 1), umbilicus deep, aperture large, irregular opening into the umbilicus with a thickened lip. [Kennett & Srinivasan 1983] Wall type:
Lam & Leckie 2020 pl11 07.jpg
Non-spinose; Cancellate [Aze 2011]
Character matrix
test outline:
Lobate
chamber arrangement:
Trochospiral
edge view:
Equally biconvex
aperture:
Umbilical
sp chamber shape:
Globular
coiling axis:
Low
periphery:
N/A
aperture border:
Thick lip
umb chbr shape:
Globular
umbilicus:
Wide
periph margin shape:
Broadly rounded
accessory apertures:
None
spiral sutures:
Moderately depressed
umb depth:
Deep
wall texture:
Cancellate
shell porosity:
Macroperforate: >2.5µm
umbilical or test sutures:
Strongly depressed
final-whorl chambers:
4-5
N.B. These characters are used for advanced search. N/A - not applicable
Biogeography and Palaeobiology
Geographic distributionTropical [Kennett & Srinivasan 1983] Low latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]
[SCOR WG138]
Isotope paleobiologyAze et al. 2011 ecogroup 3 - Open ocean thermocline; based on comparison with other species of the genus. Phylogenetic relationsSs. kochi is distinguished from Ss. seminulina seminulina by its somewhat compressed trochospiral test with more than three chambers in the final whorl. Ss. kochi developed from Ss. seminulina in the Middle Miocene. The kochi morphotype exhibits a somewhat different stratigraphic range from Seminulina seminulina and therefore is probably phylogenetically distinct. [Kennett & Srinivasan 1983]
Most likely ancestor: Sphaeroidinellopsis disjuncta - at confidence level 4 (out of 5). Data source: Fabbrini et al. 2021, fig 8.
Biostratigraphic distribution
Geological Range: Last occurrence (top): near top of PL1 [Atl.] zone (87% up, 4.5Ma, in Zanclean stage). Data source: Wade et al. (2011), additional event; position within zone determined by linear interpolation from data in table 1 of Wade et al. (2011). First occurrence (base): within N10 zone (13.77-14.24Ma, base in Langhian stage). Data source: Kennett & Srinivasan 1983
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested.
Grey shading between taxa indicates intergrading species within an anagenetic lineage (data from
Lamyman et al. 2026).
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Primary source for this page: Kennett & Srinivasan 1983, p.210
References:
Aze, T., et al. (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews. 86: 900-927. gs
Caudri, C. M. B. (1934). Tertiary Deposits of Soemba. H. J. Paris, Amsterdam. 1-225. gs
Fabbrini, A., Zaminga, I., . Ezard, T. H. G. & Wade, B. S. (2021). Systematic taxonomy of middle Miocene Sphaeroidinellopsis (planktonic foraminifera). Journal of Systematic Palaeontology. 19(13): 953-968. gs
Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs
Lam, A. & Leckie, R. M. (2020a). Late Neogene and Quaternary diversity and taxonomy of subtropical to temperate planktic foraminifera across the Kuroshio Current Extension, northwest Pacific Ocean. Micropaleontology. 66(3): 177-268. gs
Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. gs
Sphaeroidinellopsis kochi compiled by the pforams@mikrotax project teamviewed: 18-7-2026