Subbotina triangularis


Classification: pf_cenozoic -> Globigerinidae -> Subbotina -> Subbotina triangularis
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.,

Taxonomy

Citation: Subbotina triangularis (White 1928)
Rank: Species
Basionym: Globigerina triangularis
Synonyms:
Taxonomic discussion: Shutskaya's (1970a, 1970b) references to pseudotriloba, triangularis, uruchaensis, and gerpegensis are all considered synonymous with Subbotina triangularis. The criteria she provided to distinguish between these forms and her text-illustrations are insufficient for consistent discrimination. Moreover, she (1970a: 104) included Bolli's illustration of G. triangularis (1957a, pi. 15: figs. 12-14) in the synonym of her new taxon, G. gerpegensis.
The distinctive spinose wall texture of Subbotina triangularis sets it apart from the trivialis -triloculinoides lineage and the cancellata -velascoensis lineage. Subbotina triangularis may be a stem form for a separate lineage that links with Eocene species, but this possibility has not been investigated. It may be linked with Globigerina praebulloides, which has a similar wall texture (compare Plate 2: Figures 14-16). [Olsson et al. 1999]

Catalog entries: Globigerina triangularis, Globigerina gerpegensis, Globigerina pseudotriloba Shutskaya, Globigerina uruchaensis

Type images:

Distinguishing features: 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.

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: Test a somewhat loose coil of 3½ chambers in the ultimate whorl, with a narrow, deep umbilicus which is sometimes obscured by an overlapping ultimate chamber. Shape of test triangular in umbilical view, the ultimate chamber often smaller than the penultimate one, low oval in shape. Axial periphery broadly rounded. Aperture umbilical to slightly extraumbilical in position, bordered by a thin, sometimes irregular lip. The wall is cancellate, spinose with an asymmetricallydeveloped pore pattern and well developed coalescing spine collars. [Olsson et al. 1999]

Character matrix

test outline:Triangularchamber arrangement:Trochospiraledge view:Inequally biconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Lowperiphery:N/Aaperture border:Thick lip
umb chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Strongly depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:3.0-3.5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Apparently this species global distribution in the low to middle latitudes.
has a [Olsson et al. 1999]
Aze et al. 2011 summary: Low to middle latitudes; based on Olsson et al. (1999)

Isotope paleobiology: Subbotina triangularis displays a more positive ∂18O and more negative ∂13C than coexisting Morozovella and Acarinina (D'Hondt et al., 1994). The species shows little change in ∂18O or ∂13C over a large size range (D'Hondt et al., 1994). [Olsson et al. 1999]
Aze et al. 2011 ecogroup 2 - Open ocean mixed-layer tropical/subtropical, without symbionts. Based on δ13C lighter than species with symbionts; also with relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): D'hondt et al. (1994); Coxall et al. (2000)

Phylogenetic relations: This species probably evolved from S. triloculinoides in Zone P3 by developing a more evolute coil, by increasing its test size, and by achieving a more asymmetical pore pattern with well-developed coalescing spine collars. [Olsson et al. 1999]

Most likely ancestor: Subbotina trivialis - at confidence level 4 (out of 5). Data source: Olsson et al. 1999 f5a.
Likely descendants: Subbotina roesnaesensis;

Biostratigraphic distribution

Geological Range:
Notes: Zone P2 to Zone P5, ? P6. [Olsson et al. 1999]
Last occurrence (top): within P5 zone (55.96-57.10Ma, top in Thanetian stage). Data source: Olsson et al. 1999
First occurrence (base): within P2 zone (62.29-62.60Ma, base in Danian stage). Data source: Olsson et al. 1999

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 30

References:

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs

Bolli, H. M. (1957d). The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation 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: 61-82. gs

Loeblich, A. R. & Tappan, H. (1957b). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. 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: 173-198. gs

Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. 1-252. gs

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

Shutskaya, E. K. (1970a). Morphologic groups and descriptions of species of Globigerina and Acarinina in the lower Paleogene of the Crimea, the Caucasus Foreland, and western Central Asia. Trudy Instituta Vsesoyuznyy NauchnoIssledovatel'skiy Geologorazvedochnyy Neftyanot Institut. 69: 79-113. gs

Shutskaya, E. K. (1970b). Stratigrafiya, foraminifery i paleogeografiya nizhnego paleogena Kryma, predkavkaz'ya i zapadnoi chadsti srednei azii [Stratigraphy, Foraminifera and Paleogeography of the Lower Paleogene in the Crimea, Precaucasus and the Western Part of Central Asia]. Trudy, Vsesoyuznyi Nauchno-lssledovadetel 'skii Geologorazvedochnyi Neftyanoi Institut (VNIGNI). 70(1): 256-. gs

Tjalsma, R. C. (1977). Cenozoic Foraminifera from the South Atlantic, DSDP Leg 36. Initial Reports of the Deep Sea Drilling Project. 36: 493-518. gs

White, M. P. (1928). Some Index Foraminifera of the Tampico Embayment Area of Mexico. Journal of Paleontology. 2(3): 177-215. gs


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Subbotina triangularis compiled by the pforams@mikrotax project team viewed: 17-11-2019

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