Globorotalia theyeri


Classification: pf_cenozoic -> Globorotaliidae -> Globorotalia -> hirsuta lineage -> Globorotalia theyeri
Sister taxa: G. hirsuta, G. theyeri, G. margaritae, G. juanai, G. bermudezi, G. scitula, G. praescitula, G. cibaoensis, G. gigantea, G. challengeri,

Taxonomy

Citation: Globorotalia theyeri Fleisher, 1974
Rank: species
Basionym: Globorotalia theyeri Fleisher, 1974
Synonyms:

Catalog entries: Globorotalia (Hirsutella) theyeri, Globorotalia hirsuta eastropacia

Type images:

Distinguishing features: Distinct but thin peripheral keel and strongly recurved spiral sutures, lobate outline

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: Large, thin, planoconvex to biconvex, markedly flaring chambers in final whorl with a thin discontinous peripheral keel
Aperture: Interiomarginal umbilical-extraumbilical low arch bordered by a distinct but thin lip 
Coiling direction (in extant population): mixed with bias to dextral [Aze 2011, based on Kennett & Srinivasan 1983]

Test large, thin, planoconvex to unequally biconvex, equatorial periphery lobulate with markedly flaring chambers in the final whorl; axial periphery acute, with thin, discontinuous peripheral keel; four to five chambers in the final whorl, increasing moderately to rapidly in size; spiral sutures strongly recurved, depressed, on umbilical side gently curved, to radial, depressed; surface finely and uniformly perforate; umbilicus large, deep; aperture interiomarginal, umbilical-extraumbilical a low arch bordered by a distinct but thin lip. [Kennett & Srinivasan 1983]


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

Size: >150µm

Character matrix

test outline:Stellatechamber arrangement:Trochospiraledge view:Inequally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Crescenticcoiling axis:Lowperiphery:Single keelaperture border:Thick lip
umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:None
spiral sutures:Weakly depressedumb depth:Shallowwall texture:Smoothshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Weakly depressedfinal-whorl chambers:4.0-5.0 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 Kennett & Srinivasan (1983)]

In modern oceans a common, temperate water, species [SCOR WG138]


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.) theyeri evolved from Gr. (H.) margaritae from which it is distinguished by its distinctly flattened spiral side, its flaring chambers of the final whorl, and a relatively large umbilicus. [Kennett & Srinivasan 1983]


Similar species: This species differs from Gr. (H.) scitula in having a distinct but thin peripheral keel and more strongly recurved spiral sutures. [Kennett & Srinivasan 1983]

Most likely ancestor: Globorotalia margaritae - at confidence level 3 (out of 5). Data source: Kennett & Srinivasan 1983, fig 15; Stewart 2003 fig. 6.10; Aze et al. 2011, appendix 5.
Likely descendants: Globorotalia hirsuta;

Biostratigraphic distribution

Geological Range:
Notes: Early Pliocene Zone N19 to Recent. Tropical. [Kennett & Srinivasan 1983]
Last occurrence (top): Extant Data source: present in the plankton (SCOR WG138)
First occurrence (base): within N19 zone (4.37-5.20Ma, base in Zanclean stage). Data source: Kennett & Srinivasan 1983

Plot of occurrence data:

Primary source for this page: Kennett & Srinivasan 1983, p.140

References:

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

Fleisher, R. L. (1974a). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project. 23: 1001-1072. gs

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


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Globorotalia theyeri compiled by the pforams@mikrotax project team viewed: 18-10-2019

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