Globorotalia juanai

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

Distinguishing features: Like G. scitula but periphery rounded and early chambers umbonate


Citation: Globorotalia juanai Bermudez & Boli 1969
Rank: species
Basionym: Globorotalia juanai
Synonyms: NB Globorotalia margaritae primitiva Cita was also considered a synonym by Kennett & Srinivasan 1983 but was regarded  regarded as a distinct sub-species by Stewart (2003) and Aze et al. (2011).

Catalog entries: Globorotalia andalusiana; Globorotalia juanai;
Globorotalia martinezi; Globorotalia praemargaritae;

Type images:

Distinguishing features: Like G. scitula but periphery rounded and early chambers umbonate

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.


Diagnostic characters: Small, very low trochospiral, biconvex, equatorial periphery slightly lobate

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

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

Test morphology: Test small, very low trochospiral, biconvex, equatorial periphery slightly lobulate ; axial periphery rounded with a tendency to become subangular; chambers inflated on umbilical side, 4 to 4½ in the final whorl, increasing moderately to rapidly in size; sutures on spiral side oblique, depressed , on umbilical side radial, depressed; surface smooth, finely and densely perforate, pustulate on early chambers on umbilical side; umbilicus narrow; aperture interiomarginal, extraumbilical-umbilical, a low arch or slit bordered by a thin lip. [Kennett & Srinivasan 1983]

Biogeography and Palaeobiology

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

[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) juanai is distinguished from Gr. (H) scitula and Gr. (H) margaritae by its rounded periphery and umbonate early chambers. We are in agreement with Stainforth et al. (1975) that Gr. (H) juanai was a direct descendant of Gr. (H) scitula, and, in turn, developed into the Gr. margaritae-Gr. hirsuta bioseries. [Kennett & Srinivasan 1983]

Most likely ancestor: Globorotalia scitula - at confidence level 3 (out of 5). Data source: Kennett & Srinivasan (1983) NB Stewart 2003 fig. 6.10; Aze et al. 2011, appendix 5 suggest juanai and praemargaritae are separate species and that juanai is closer to challengeri.

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within N18 zone (5.20-5.72Ma, top in Zanclean stage). Data source: Chaisson & Pearson (1997)
First occurrence (base): near base of M13a subzone (13% up, 9.7Ma, in Tortonian 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 & Srinivasan 1983, p.134


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.

Bermudez, P.J. & Bolli, H.M., (1969). Consideraciones sobre los sedimentos del mioceno medio al reciente de las costas central y oriental de Venezuela. Tercera Parte. Los foraminiferos planctonicos. Boletin de Geologia, 10(20): 137-223.

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

Perconig, E., (1968). Nuove specie di foraminiferi planctonici della Sezione di Carmona (Andalusia, Spagna). Committee Mediterranean Neogene Stratigraphy, 35(3): 219-232.

Stainforth, R.M.; Lamb, J.L.; Luterbacher, H.; Beard, J.H. & Jeffords, R.M., (1975). Cenozoic planktonic foraminiferal zonation and characteristics of index forms. The University of Kansas Paleontological Contributions, 62: 1-425.


Globorotalia juanai compiled by the pforams@mikrotax project team viewed: 22-3-2018

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