Subbotina


Classification: pf_cenozoic -> spinose -> Globigerinidae -> Subbotina
Sister taxa: Catapsydrax, Eoglobigerina, Globigerina, Globigerinatheka, Globorotaloides, Globoturborotalita, Guembelitrioides, Orbulinoides, Paragloborotalia, Parasubbotina, Pseudoglobigerinella, Subbotina, Turborotalita,
Daughter taxa - sorted by lineage and stratigraphically (blue => in age window 0-300Ma)
triangularis group
Very low trochospiral, lobulate test with 3½-4 rapidly enlarging, ovoid-shaped, loosely embracing chambers, and ruber-type wall texture.
Like S. eocaena but with more spherical chambers, a large, prominent, apertural tooth.
Test globular, chambers much embracing. Final chamber reduced, projecting over and covering the umbilicus.
Large adult test, lobulate with moderately elevated initial spire. Chambers globular, final chamber cantilevered and directed over the umbilicus.
Large adult test, quadrate. Chambers globular, embracing. Aperture low-arched, umbilical-extraumbilical, with thin irregular lip.
Large adult test with globular, embracing, chambers. Aperture low-arched, with thin irregular lip.
Test trochospiral, loosely coiled, with globular chambers, and umbilical aperture.
Chambers globular, slightly embracing. Aperture characteristically crooked, high-arched, and with prominent regular lip.
Test lobulate, moderately elevated trochospire. Aperture with somewhat broad lip that tapers both anteriorly and posteriorly.
Globular moderately elevated trochospiral test. Thick calcite crust covers and closes pores, and surrounds the umbilicus.
Test triangular in umbilical view, axial periphery broadly rounded. 3½ loosely coiled chambers in final whorl. Final chamber low oval, often smaller than the one before. Umbilicus narrow, deep, sometimes obscured by final chamber. Aperture umbilical to slightly extraumbilical, with a thin, sometimes irregular lip. Wall cancellate, spinose.
cancellata group
Differs from Subbotina linaperta (Finlay) by more compact coiling, more equidimensional size of final whorl chambers; lower and more umbilical aperture, with less-developed lip; also less coarsely cancellate wall texture. Differs from S. angiporoides by not possessing an enveloping final chamber.
Final chamber on most individuals strongly embracing, resembling a bulla and extending over the umbilicus. Aperture, centered over the antepenultimate chamber; low, slit-like with thick lip. Prepenultimate chambers tend to be more globular than in the final whorl chambers of S. linaperta.
Test low trochospiral, globular, with 3-3⅓ chambers in final whorl. Final chamber large and compressed. Apeture highly arched, with well-developed lip. Wall texture coarsely cancellate.
Test compact, low trochospiral, with 3-3½ rapidly enlarging chambers. Aperture arched, semicircular. Wall texture coarsely cancellate, sacculifer-type.
Test compact, low trochospiral with 3½ to nearly 4 globular embracing chambers in final whorl. Final chamber reduced and directed over the umbilicus. Wall texture coarsely cancellate, sacculifer-type.
Test tightly coiled, compact, rounded, and slightly lobulate; 3½-4 chambers in final whorl. Aperture umbilical with broad, somewhat irregular lip. Wall coarsely cancellate on all chambers.
Test tightly coiled, subquadrate, test with compressed chambers. Final chamber much compressed, elongate, forms about half of the test and typically overhangs the earlier chambers. Aperture umbilical; thin elongate lip along part of aperture with squared-of ends. The test wall is coarsely and symmetrically cancellate, spinose.
Test medium sized, lobulate, trilobate with 3-3½ chambers in final whorl, increasing moderately in size. The ultimate chamber forms up to ½ of the test. Intercameral sutures depressed, straight to slightly curved on umbilical and spiral sides of the test. Umbilicus narrow, deep, often covered by a well developed apertural lip. Aperture umbilical, slightly asymmetrical towards an extraumbilical direction. The test walls strongly cancellate, spinose.
Test small (<250µm) low trochospiral, tightly coiled with 3½ chambers in final whorl Aperture umbilical with a thin lip. The ultimate chamber is equal to, or slightly smaller than the penultimate one. The wall is weakly cancellate and spinose. The spines are set at the junctures of the cancellate ridges. The umbilicus is small and nearly closed by the tight coiling.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Subbotina Brotzen and Pozaryska, 1961
Rank: Genus
Type species: Globigerina triloculinoides Plummer, 1926, emended.
Taxonomic discussion: Most species included in this genus were originally described as Globigerina. However, they differ in having a sacculifer or sacculifer/ruber-type wall (with the possible exceptions of S. roesnaesensis n. sp. and S. crociapertura, which show transition to the bulloides-type wall). Subbotina is distinguished from Globoturborotalita by its larger size, generally more embracing chambers and more asymmetrical aperture. Subbotina was emended to include the spinose wall texture by Olsson and others (1999). In some Eocene species extensive, heavy gametogenic calcification is observed. This apparently reflects a greater range of adaptation to the water column in the Eocene although isotope data indicates that most species were thermocline dwelling forms.
[Olsson et al. 2006]

Catalog entries: Subbotina;

Type images:

Distinguishing features: Low trochospiral, tripartite test with 10-12 chambers, with 3-4 rapidly inflating, globular chambers in ultimate whorl. Aperture interiomarginal, umbilical to slightly extraumbilical in most species, a low arch. Apertural lip varies from narrow to fairly broad with a distinct apparatus extending over umbilicus. Umbilicus small and nearly closed by tight coiling. Wall cancellate and spinose; spines set at juncture of the cancellate ridges with or without spine collars. Cancellate texture varies from weak to very strong and from moderate to very coarse or distinctly honeycombed.

NB The short diagnoses are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They have initially been copied from the diagnostic characters/distinguishing features sections of the Eocene and Paleocene Atlases, they will be edited as the site is developed.

Description


Diagnostic characters: Low trochospiral, tripartite test with 10-12 chambers, with 3-4 rapidly inflating, globular chambers in ultimate whorl. Aperture interiomarginal, umbilical to slightly extraumbilical in most species, a low arch. Apertural lip varies from narrow to fairly broad with a distinct apparatus extending over umbilicus. Umbilicus small and nearly closed by tight coiling. Wall cancellate and spinose; spines set at juncture of the cancellate ridges with or without spine collars. Cancellate texture varies from weak to very strong and from moderate to very coarse or distinctly honeycombed.
[Olsson et al. 2006]

Biogeography and Palaeobiology


Phylogenetic relations: Subbotina evolved from Eoglobigerina eobulloides in the lower part of Zone P_. Globoturborotalita and Globigerina have their origin in the genus Subbotina.
[Olsson et al. 2006]

Most likely ancestor: Eoglobigerina - at confidence level 0 (out of 5). Data source: .

Biostratigraphic distribution

Geological Range:
Notes: Base of Zone P_ to the top of O6.
Plummer, 1926.
[Olsson et al. 2006]
Last occurrence (top): in upper part of Chattian Stage (57% up, 25.2Ma, in Chattian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Danian Stage (0% up, 66Ma, in Danian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Olsson et al. 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 6, p. 125

References:

Olsson, R.K.; Hemleben, C.; Huber, B.T. & Berggren, W.A., (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Globigerina, Globoturborotalita, Subbotina, and Turborotalita. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Allen Press, Lawrence, Kansas, pp. 111-168.

Plummer, H.J., (1926). Foraminifera of the Midway formation in Texas. University of Texas Bulletin, 2644: 1-206.


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Subbotina compiled by the pforams@mikrotax project team viewed: 25-6-2018

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