pforams@mikrotax - Subbotina yeguaensis pforams@mikrotax - Subbotina yeguaensis

Subbotina yeguaensis

Classification: pf_cenozoic -> Globigerinidae -> Subbotina -> Subbotina yeguaensis
Sister taxa: S. projecta, S. tecta, S. jacksonensis, S. corpulenta, S. eocaena, S. gortanii, S. crociapertura, S. yeguaensis, S. senni, S. roesnaesensis ⟩⟨ S. utilisindex, S. angiporoides, S. minima, S. linaperta, S. patagonica ⟩⟨ S. cancellata, S. hornibrooki, S. velascoensis, S. triloculinoides, S. triangularis, S. trivialis, S. sp.


Citation: Subbotina yeguaensis (Weinzierl&Applin 1929)
taxonomic rank: Species
Basionym: Globigerina yeguaensis
Taxonomic discussion: Blow (1979) included Subbotina yeguaensis in his new genus Dentoglobigerina, believing that it was an intermediate species between D. galavisi (Bermúdez) and D. pseudovenezuelana (Blow and Banner). This was apparently based on his concept of a “central type” for D. galavisi, which are forms from the middle Eocene. However, these forms do not fit the central morphology of D. galavisi which was described from the upper Eocene Jackson Formation, Mississippi, which spans from Zones E15-16 (see holotype Pl. 13.1, Figs. 1-3, this volume and discussion under D. galavisi). Subbotina yeguaensis is spinose and lacks the triangular lip that characterizes the nonspinose genus Dentoglobigerina and, therefore, cannot be placed as an intermediate species in a Dentoglobigerina lineage.
Subbotina yeguaensis was described from the middle Eocene subsurface of Louisiana where it is common. The holotype of Subbotina pseudoeocaena (Subbotina) which is described from the lower/middle Eocene of the northern Caucasus has the morphologic characteristics of S. yeguaensis and is considered a junior synonym (see Pl. 6.18, Figs. 13-15), as is Subbotina angiporoides lindiensis of Blow (1979) and possibly Globigerina pseudoeocaena Subbotina var. ellipsocamerata Khalilov (1956; viewed by WAB). [Olsson et al. 2006]

Catalog entries: Globigerina yeguaensis, Globigerina pseudoeocaena, Subbotina angiporoides lindiensis

Type images:

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 lobulate, moderately elevated trochospire. Aperture with somewhat broad lip that tapers both anteriorly and posteriorly.

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.


Test moderately elevated, trochospiral, globular, lobulate in outline, chambers globular; in spiral view 3 1/3 globular, slightly embracing chambers in ultimate whorl, increasing moderately in size, ultimate chamber may be equal to or smaller in size than penultimate chamber, sutures moderately depressed, straight; in umbilical view 3 1/3 globular, slightly embracing chambers, increasing moderately in size, sutures moderately depressed, straight, umbilicus small, enclosed by surrounding chambers, aperture umbilical, bordered by a somewhat broad lip that tapers both anteriorly and posteriorly, ultimate chamber may be equal to or smaller than the penultimate chamber; in edge view moderately elevated trochospire, chambers globular in shape, somewhate embracing, aperture visible as a low rounded opening, bordered by a somewhat broad lip. [Olsson et al. 2006]

Wall type:
Normal perforate, symmetrically cancellate, sacculifer-type wall texture, spinose. [Olsson et al. 2006]

Maximum diameter of holotype 0.52 mm, thickness 0.40 mm. [Olsson et al. 2006]

Character matrix
test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Moderate-highperiphery:N/Aaperture border:Thick lip
umb chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Deepwall texture:Cancellateshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:3-3 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

Global in low to high latitudes. [Olsson et al. 2006]
Aze et al. 2011 summary: Cosmopolitan; based on Olsson et al. (2006a)

Isotope paleobiology
Boersma and others (1987) record strongly positive δ18O for this species indicating a deep planktonic habitat. [Olsson et al. 2006]
Aze et al. 2011 ecogroup 4 - Open ocean sub-thermocline. Based on very light _13C and very heavy _18O. Sources cited by Aze et al. 2011 (appendix S3): Boersma et al. (1987); Coxall et al. (2000)

Phylogenetic relations
Subbotina yeguaensis belongs to a group of subbotinids with symmetrical cancellate (sacculifer-type) wall texture. It apparently arose in the early Eocene, possibly from S. eocaena. [Olsson et al. 2006]

Most likely ancestor: Subbotina roesnaesensis - at confidence level 4 (out of 5). Data source: Olsson et al. 2006 f6.2.
Likely descendants: Dentoglobigerina galavisi; Subbotina crociapertura; Subbotina gortanii; plot with descendants

Biostratigraphic distribution

Geological Range:
Notes: Zone E7 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 E7 zone (45.72-50.20Ma, base in Ypresian stage). Data source: Eocene Atlas

Plot of occurrence data:

Primary source for this page: Olsson et al. 2006 - Eocene Atlas, chap. 6, p. 162


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Bolli, H. M. (1957a). Planktonic foraminifera from the Eocene Navet and San Fernando formations of Trinidad. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin . 215: 155-172. gs

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Khalilov, D. M. (1956). 0 pelagicheskoy faune foraminifer Paleogenovykh otlozheniy Azerbaydzhana [Pelagic Foraminifera of the Paleogene Deposits of the Azerbaizhan SSR]. Trudy Instituta Geologii, Akademiya Nauk Azerbaidzhanskoi SSR. 17: 234-255. gs

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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. gs O

Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. gs

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Warraich, M. Y. & Ogasawara, K. (2001). Tethyan Paleocene-Eocene planktic foraminifera from the Rakhi Nala and Zinda Pir land sections of the Sulaiman Range, Pakistan. Science Reports of the Institute of Geosciences, University of Tsukuba. 22: 1-59. gs

Weinzierl, L. L. & Applin, E. R. (1929). The Claiborne Formation on the Coastal Domes. Journal of Paleontology. 3(4): 384-410. gs


Subbotina yeguaensis compiled by the pforams@mikrotax project team viewed: 22-5-2024

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