Globigerinarotundatajacksonensis Bandy, 1949:121, pl.23: fig. 6a-c [upper Eocene, Yazoo Clay, Little Stave Creek, Clarke County, Alabama].
Globigerinaouachitaensissenilis Bandy, 1949:121, pl.22: fig. 5a-c [upper Eocene, Yazoo Clay, Little Stave Creek, Clarke County, Alabama].
Globigerina (Eoglobigerina) bizkaiensis Orue-Etxebarria, 1985: 469 pl.1, figs. 1-10 [middle Eocene Globigerinathekasubconglobata and Globorotalia (Morozovella) lehneri Zones, Province of Bizkaia, Spain].
Not Globigerinasenilis Bandy.— Blow and Banner, 1962: 95, pl. XI, figs. r, s, t, u.
Taxonomic discussion: We illustrate in SEM for the first time the holotype of Subbotina jacksonensis (Pl.6.13, Figs. 1-3). This species has been apparently overlooked by workers, or grouped with other subbotinid species, or placed in Catapsydrax. The ultimate chamber, even though it projects over and covers the umbilicus, cannot be regarded as a bulla. It represents the terminal stage in the ontogeny of the individual and shows varying degrees of wall texture development among individuals of the species, a common feature in planktonic foraminifera. The species is fairly common in our upper Eocene samples. Globigerinaouachitaensis senilis Bandy was described from a sample in the Yazoo Clay close to the sample from which S. jacksonensis was described. Globigerina senilis was described as having a small ultimate chamber that restricts the opening to the umbilicus, which is observed within the normal range of morphologic variation in S. jacksonensis. SEM images of Globigerina (Eoglobigerina) bizkaiensis Orue -Etxebarria from the middle Eocene of Spain are identical with holotype and other images of S. jacksonensis. [Olsson et al. 2006]
Distinguishing features: Parent taxon (Subbotina): Low trochospiral, tripartite test, with 3-4 rapidly inflating, globular chambers in final whorl.
Umbilicus nearly closed by tight coiling.
Wall cancellate with spines at nodes of the ridges, +/- spine collars. This taxon: Test globular, chambers much embracing. Final chamber reduced, projecting over and covering the umbilicus.
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.
Description
Diagnostic characters: The species is characterized by its globular test, much embracing chambers, with a reduced ultimate chamber projecting over and covering the umbilicus. [Olsson et al. 2006]
Character matrix
test outline:
Lobate
chamber arrangement:
Trochospiral
edge view:
Equally biconvex
aperture:
Umbilical
sp chamber shape:
Globular
coiling axis:
Low-moderate
periphery:
N/A
aperture border:
N/A
umb chbr shape:
Globular
umbilicus:
Narrow
periph margin shape:
Broadly rounded
accessory apertures:
None
spiral sutures:
Moderately depressed
umb depth:
Deep
wall texture:
Spinose
shell porosity:
Finely Perforate: 1-2.5µm
umbilical or test sutures:
Moderately depressed
final-whorl chambers:
3-4
N.B. These characters are used for advanced search. N/A - not applicable
Biogeography and Palaeobiology
Geographic distributionGlobal in low-to mid-latitudes. [Olsson et al. 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Olsson et al. (2006a) Isotope paleobiologyNo data available. [Olsson et al. 2006] Aze et al. 2011 ecogroup 3 - Open ocean thermocline. Based on light _13C and relatively heavy _18O. Sources cited by Aze et al. 2011 (appendix S3): Coxall et al. (2000) Phylogenetic relationsSubbotinajacksonensis probably evolved from Subbotinaeocaena by developing more embracing chambers and a reduced ultimate chamber that projects over the umbilicus. [Olsson et al. 2006]
Most likely ancestor:Subbotina eocaena - at confidence level 4 (out of 5). Data source: Olsson et al. 2006 f6.2.
Biostratigraphic distribution
Geological Range: Notes: Zone E9 (upper part) to Zone E16. [Olsson et al. 2006] Last occurrence (top): within E16 zone (33.90-34.68Ma, top in Priabonian stage). Data source: Eocene Atlas First occurrence (base): within E9 zone (43.23-43.85Ma, base in Lutetian stage). Data source: Eocene Atlas
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
(NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Subbotina
Primary source for this page: Olsson et al. 2006 - Eocene Atlas, chap. 6, p. 146
References:
Bandy, O. L. (1949). Eocene and Oligocene foraminifera from Little Stave Creek, Clarke County, Alabama. Bulletins of American Paleontology. 32(131): 1-210. gs
Blow, W. H. & Banner, F. T. (1962). The mid-Tertiary (Upper Eocene to Aquitanian) Globigerinaceae. In, Eames, F. E., Banner, F. T., Blow, W. H. & Clarke, W. J. (eds) Fundamentals of mid-Tertiary Stratigraphical Correlation. Cambridge University Press, Cambridge 61-151. gs
Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (2006a). Taxonomy, biostratigraphy, and phylogeny of Eocene Globigerina, Globoturborotalita, Subbotina, and Turborotalita. In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 6): 111-168. gsO
Subbotina jacksonensis compiled by the pforams@mikrotax project teamviewed: 29-4-2025