Globorotalia margaritae

NB TAXA WHICH ORIGINATE IN THE OLIGOCENE ARE NOT INCLUDED YET
Classification: pf_neogene -> Globorotalidae -> Globorotalia -> hirsuta lineage -> Globorotalia margaritae
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 margaritae Bolli & Bermudez 1965
Rank: species
Basionym: Globorotalia margaritae
Synonyms:

Catalog entries: Globorotalia margaritae;

Type images:

Description


Diagnostic characters: Low trochospiral, compressed, spiral side convex, umbilical side concave with thin keel

Aperture: : Interiomarginal umbilical-extraumbilical low slit bordered by a pronounced lip [Aze 2011, based on Kennett & Srinivasan 1983]


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

Test morphology: Test low trochospiral, compressed, spiral side convex, umbilical side concave to almost flat, equatorial periphery slightly lobulate, axial periphery acute with a thin keel; chambers strongly compressed, 5 in the final whorl, increasing rapidly in size; sutures on spiral side strongly curved, limbate, slightly raised, on umbilical side gently curved, depressed; surface coarsely and densely perforate, early chambers slightly pustulose, later chambers smooth. Umbilicus narrow; aperture a low slit bordered by a pronounced lip, interiomarginal, extraumbilical-umbilical. [Kennett & Srinivasan 1983]

Biogeography and Palaeobiology


Geographic distribution: Tropical to 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: Gr. (H.) margaritae differs from its ancestral forms Gr. (H.) scitula and Gr. (H.) juanai by its more convexly rounded spiral side and concave to flat umbilical side, in its more delicate peripheral keel, and in the distinctly elongate, narrower, and more strongly curved chambers as viewed from the spiral side.
Gr. (H) margaritae evolved from Gr. (H.) juanai by an increase in chamber numbers in the final whorl and by development of a convexly rounded spiral side and a relatively narrow keel. This species is ancestral to Gr. (H) theyeri Fleisher and Gr. (H) hirsuta (d'Orbigny). [Kennett & Srinivasan 1983]

Biostratigraphic distribution

Geological Range:
Notes: Gr. (H) margaritae has a short stratigraphic range and is a generally recognized index species for the tropical to temperate Early Pliocene (Bolli, 1970; Srinivasan et al.,1981) .
Last occurrence (top): at top of PL2 zone (100% up, 3.9Ma, in Zanclean stage). Data source: Wade et al. (2011), zonal marker
First occurrence (base): near base of M14 [Atl.] zone (14% up, 6.1Ma, in Messinian stage). Data source: Wade et al. (2011), additional event; position within zone determined by linear interpolation from data in table 1 of Wade et al. (2011).

Plot of occurrence data:

Primary source for this page: Kennett & Srinivisan 1983, p.136

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.

Bolli, H.M. & Bermudez, P.J., (1965). Zonation based on planktonic foraminifera of middle Miocene to Pliocene warm-water sediments. Bol. Informativo, Asoc. Venez. Geol., Min. Petrol., 8(5): 121-149.

Cita, M.B., (1973). Pliocene biostratigraphy and chronostratigraphy. Initial Reports of the Deep Sea Drilling Project, 13: 1343-1379.

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


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Globorotalia margaritae compiled by the pforams@mikrotax project team viewed: 24-9-2017

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