Globigerinoides mitra


Classification: pf_cenozoic -> Globigerinidae -> Globigerinoides -> Globigerinoides mitra
Sister taxa: G. elongatus, G. extremus, G. conglobatus, G. eoconglobatus, G. obliquus, G. altiaperturus, G. joli, G. neoparawoodi, G. kennetti, G. bollii, G. italicus, G. ruber, G. mitra, G. seigliei, G. subquadratus, G. diminutus, G. bulloideus, G. sp.,

Taxonomy

Citation: Globigerinoides mitra Todd 1957
Rank: species
Basionym: Globigerinoides mitra
Synonyms:

Catalog entries: Globigerinoides mitra

Type images:

Distinguishing features: Large test with very high spire, and large, asymmetric primary aperture

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: Large, high trochospiral, spherical to subspherical chambers

Aperture: : Interiomarginal umbilical-extraumbilical large semi-circular opening. Supplementary sutural apertures on spiral side [Aze 2011, based on Kennett & Srinivasan 1983]


Wall type: Spinose; Cancellate [Aze 2011]

Test morphology: Test large , high spired, chambers spherical to suhspherical, three or four in the final whorl; sutures depressed, surface hummocky on earlier chambers but perforate on later chambers; primary aperture interiomarginal, umbilical, a large semicircular opening occupying most of the umbilical edge of the final chamber; small supplementary apertures at the intersection of the vertical sutures with the spiral sutures. [Kennett & Srinivasan 1983]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Highperiphery:N/Aaperture border:N/A
umb chbr shape:Elongateumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:Sutural
spiral sutures:Strongly depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:3.0-4.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Tropical [Kennett & Srinivasan 1983] Low latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]

[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 et al. (2001b)

Phylogenetic relations:

Gs. mitra is distinguished by its large test size, very high spire, and large, asymmetric primary aperture. Except for its distinct asymmetrically developed adult chambers, Gs. mitra is morphologically close to Gs. subquadratus and Gs. ruber and possibly is intermediate between them.
Saito et al. (1976) placed Gs. mitra under a new genus, Globicuniculus, stating that it lacks the characteristic elongate spines or the spine bases of the genus Globigerinoides. Todd (1957) described the form as being finely spinose, and thus generic differentiation is not justified on these grounds. However, the form exhibits distinctive smooth surface texture that may be significant taxonomically. [Kennett & Srinivasan 1983]

Most likely ancestor: Globigerinoides subquadratus - at confidence level 3 (out of 5). Data source: Kennett & Srinivasan 1983, fig. 10.

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within N12 zone (11.79-13.41Ma, top in Serravallian stage). Data source: Kennett & Srinivasan 1983
First occurrence (base): within N6 zone (17.54-17.59Ma, base in Burdigalian stage). Data source: Kennett & Srinivasan 1983

Plot of occurrence data:

Primary source for this page: Kennett & Srinivasan 1983, p.76

References:

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

Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs

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

Pearson, P. N. et al. (2001a). Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs. Nature. 413: 481-487. gs

Saito, T., Thompson, P. R. & Breger, D. (1976). Skeletal ultra-microstructure of some elongate-chambered planktonic foraminifera and related species. In, Takayanagi, Y. & Saito, T. (eds) Progress in Micropaleontology, Special Publication. Micropaleontology Press, The American Museum of Natural History, New York 278-304. gs

Todd, R. (1957). Smaller foraminifera, in Geology of Saipan, Mariana Islands, Pt. 3, Paleontology. U. S. Geological Survey, Professional Paper. 280-H: 265-320. gs


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Globigerinoides mitra compiled by the pforams@mikrotax project team viewed: 17-10-2019

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