Globorotalia challengeri

NB TAXA WHICH ORIGINATE IN THE OLIGOCENE ARE NOT INCLUDED YET
Classification: pf_neogene -> Globorotalidae -> Globorotalia -> hirsuta lineage -> Globorotalia challengeri
Sister taxa: G. challengeri, G. cibaoensis, G. gigantea, G. hirsuta, G. juanai, G. margaritae, G. margaritae evoluta, G. praemargaritae, G. praescitula, G. primitiva, G. scitula, G. theyeri,

Taxonomy

Citation: Globorotalia challengeri Srinivasan & Kennett 1981
Rank: species
Basionym: Globorotalia challengeri Srinivasan & Kennett 1981
Synonyms:

Catalog entries: Globorotalia challengeri;

Type images:

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, unequally biconvex, equatorial periphery lobate

Aperture: : Interiomarginal umbilical-extraumbilical distinct arch with a prominent lip [Aze 2011, based on Kennett & Srinivasan 1983]


Wall type: Non-spinose; Smooth [Aze 2011]

Test morphology: Test a fairly low trochospiral, unequally biconvex, equatorial periphery lobate, axial periphery rounded or with a tendency to become subangular, wall calcareous, thin, coarsely perforate , surface smooth; chambers twelve to fifteen, arranged in three whorls, 5 to 5½ chambers in the final whorl,which increases slowly in size; chambers strongly inflated especially in the later stage; rounded to ovate in shape; sutures on spiral side curved, depressed; on umbilical side slightly sinuous to radial, depressed; aperture a distinct arch, with a prominent lip, interiomarginal, umbilical-extraumbilical; coiling predominantly sinistral. [Kennett & Srinivasan 1983]

Biogeography and Palaeobiology


Geographic distribution: Temperate [Kennett & Srinivasan 1983]

Isotope paleobiology: Aze et al. 2011 ecogroup 4 - Open ocean sub-thermocline. Based on comparison with other species of the genus

Phylogenetic relations: This species differs from its ancestor, Gr. (G.) praescitula, in exhibiting 5 to 5½ rather than 4½ chambers in the final whorl, more inflated chambers, and a more rounded periphery. The species is also morphologically similar to Gr. (J.) mayeri but differs in being less elongate in equatorial profile and in exhibiting a distinctly low-arched aperture.
An evolutionary gradation was observed in DSDP Site 281 (Subantarctic) from Gr. (G.) praescitula in the latest Early Miocene to Gr. (H) challengeri in the early Middle Miocene. The morphological gradation largely involves an increase in the number of chambers, greater inflation of the test, and rounding of the periphery. The evolutionary change takes place over a period of about 2 my from the lower part of the Globorotalia miozea Zone (~18 Ma) to the base of the Orbulina suturalis Zone (16 Ma). [Kennett & Srinivasan 1983]

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within N15 zone (9.83-10.46Ma, top in Tortonian stage). Data source: Kennett & Srinivasan 1983
First occurrence (base): within N9 zone (14.24-15.10Ma, base in Langhian stage). Data source: Kennett & Srinivasan 1983

Plot of occurrence data:

Primary source for this page: Kennett & Srinivisan 1983, p.142

References:

Aze, T.; Ezard, T.H.G.; Purvis, A.; Coxall, H.K.; Stewart, D.R.M.; Wade, B.S. & Pearson, P.N.P., (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews, 86: 900-927.

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

Srinivasan, M.S. & Kennett, J.P., (1981). Neogene planktonic foraminiferal biostratigraphy and evolution: equatorial to subantarctic, south Pacific. Marine Micropaleontology, 6: 499-533.


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Globorotalia challengeri compiled by the pforams@mikrotax project team viewed: 17-11-2017

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