Trilobatus bisphericus


Classification: pf_cenozoic -> Globigerinidae -> Trilobatus -> Trilobatus bisphericus
Sister taxa: T. sacculifer, T. quadrilobatus, T. immaturus, T. trilobus ⟩⟨ T. bisphericus, T. sicanus ⟩⟨ T. altospiralis, T. praeimmaturus, T. primordius, T. subsacculifer, T. sp.

Taxonomy

Citation: Trilobatus bisphericus (Todd, 1954)
Rank: species
Basionym: Globigerinoides bispherica Todd, in Todd et al. 1954
Synonyms: Globigerinoides bisphericus (Todd, 1954)

Catalog entries: Globigerinoides bispherica

Type images:

Distinguishing features: Bilobate outline, enveloping last chamber almost completely hides 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


Wall type: Spinose; Cancellate [Aze 2011]

Morphology: A short-lived species differing from its probable ancestor, G. trilobus (Reuss), in its more enveloping last chamber which almost completely hides the umbilicus. Only 2 apertures are present along the suture between the last and earlier chambers though more apertures may remain open on the spire. [Bolli & Saunders 1985]

Character matrix

test outline:Subcircularchamber arrangement:Envelopingedge view:Equally biconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Low-moderateperiphery:N/Aaperture border:
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:Sutural
spiral sutures:Moderately depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:3.0-3.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Low latitudes [Aze et al. 2011, based on Pearson et al. (1997a)]

[SCOR WG138]


Isotope paleobiology: Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy ∂13C and relatively light ∂18O. Sources cited by Aze et al. 2011 (appendix S3): Keller (1985); Pearson & Shackleton (1995)

Phylogenetic relations: Part of the evolutionary series from Trilobatus to Orbulina [editor's comment - JRY 2018]

Most likely ancestor: Trilobatus trilobus - at confidence level 4 (out of 5). Data source: Spezzaferri et al. 2015 f5.
Likely descendants: Trilobatus sicanus;

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within N9 zone (14.24-15.10Ma, top in Langhian stage). Data source: Pearson & Chaisson (1997)
First occurrence (base): within N8 zone (15.10-16.38Ma, base in Burdigalian stage). Data source: Pearson & Chaisson (1997)

Plot of occurrence data:

References:

Aze, T. et al. (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews. 86: 900-927. gs

Bolli, H. M. & Saunders, J. B. (1985). Oligocene to Holocene low latitude planktic foraminifera. In, Bolli, H. M., Saunders, J. B. & Perch-Neilsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge, UK 155-262. gs

Keller, G. (1985). Depth stratification of planktonic foraminifers in the Miocene Ocean. In, Kennett, J. P. (ed.) The Miocene Ocean: Paleoceanography and Biogeography. GSA Memoir. 163: 1-337. gs

Norris, R. D. (1998). Planktonic foraminifer biostratigraphy: Eastern Equatorial Atlantic. Proceedings of the Ocean Drilling Program, Scientific Results. 159: 445-479. gs V O

Pearson, P. N. & Shackleton, N. J. (1995). Neogene multispecies planktonic foraminifer stable isotope record, Site 871, Limalok Guyot. Proceedings of the Ocean Drilling Program, Scientific Results. 401-410. gs V O

Pearson, P. N., Shackleton, N. J. & Hall, M. A. (1997a). Stable isotopic evidence for the sympatric divergence of Globigerinoides trilobus and Orbulina universa (planktonic foraminifera). Journal of the Geological Society of London. 154: 295-302. gs

Todd, R., Cloud, P. E., Low, D. & Schmidt, R. G. (1954). Probable occurrence of Oligocene in Saipan. American Journal of Science. 252: 673-682. gs V O


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Trilobatus bisphericus compiled by the pforams@mikrotax project team viewed: 17-1-2021

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