Globigerinella molinae


Classification: pf_cenozoic -> Globigerinidae -> Globigerinella -> Globigerinella molinae
Sister taxa: G. adamsi, G. calida, G. radians, G. siphonifera, G. clavaticamerata, G. molinae, G. navazuelensis, G. obesa, G. praesiphonifera, G. pseudobesa, G. roeglina, G. megaperta, G. wagneri, G. sp.,

Taxonomy

Citation: Globigerinella molinae (Popescu and Brotea, 1989)
Rank: species
Basionym: Protentella molinae Popescu and Brotea 1989
Synonyms:
Taxonomic discussion:

The images of the holotype and paratypes of molinae reported in Popescu and Brotea (1989) show only one side and an edge view. Although described as biumbilicate, thus planispiral, they clearly show that the two sides are not identical and therefore are not completely planispiral. They are characterized by a single, small aperture and a tendency for slightly radially elongated chambers. In the Transylvanian Basin, G. molinae is a potential alternative marker for the base of the C. angulisuturalis Zone (Popescu and Brotea, 1989). [Spezzaferri et al. 2018]

Catalog entries: Protentella molinae,

Type images:

Distinguishing features: Like G. navazuelensis but slightly more radially elongated last and/or penultimate chambers and single equatorial 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:

This species is distinguished from G. navazuelensis by its slightly more radially elongated last and/or penultimate chambers and single equatorial aperture. It differs from G. clavaticamerata by having clearly less radially elongated last chambers and more planispiral coiling. It differs from G. obesa and G. praesiphonifera by the marked tendency to become planispiral in the last whorl and for the position of the aperture tending to move across the peripheral margin. [Spezzaferri et al. 2018]


Wall type: Normal perforate, spinose, probably with spines supported by spine collars, which coalesce to form ridges. It is impossible to evaluate pore concentration and pore diameter from the existing documentation.

Test morphology: Test composed of 2 whorls, initially trochospiral becoming almost planispiral in the last whorl, ovate and slightly lobulate in outline, 5-6 chambers in ultimate whorl, increasing moderately in size, the last chamber, sometimes the last two chambers of the last whorl may be slightly radially elongated, sutures depressed, straight on both sides; aperture equatorial, position at the base of the last chamber, a low arch bordered by a distinct lip. [Spezzaferri et al. 2018]

Size: Maximum diameter of holotype approximately 0.3 mm. [Spezzaferri et al. 2018]

Character matrix

test outline:Lobatechamber arrangement:Pseudoplanispiraledge view:Equally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Globularcoiling axis:Very lowperiphery:N/Aaperture border:Thick lip
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Strongly depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:5.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Paratethys, South Atlantic and Indian Ocean (Popescu and Brotea, 1989, Spezzaferri, 1994). [Spezzaferri et al. 2018]

Isotope paleobiology: No data available. [Spezzaferri et al. 2018]

Phylogenetic relations: It probably evolved from G. navazuelensis in the lower Oligocene Zone O4. [Spezzaferri et al. 2018]

Most likely ancestor: Globigerinella navazuelensis - at confidence level 2 (out of 5). Data source: .

Biostratigraphic distribution

Geological Range:
Notes: Upper part of Zone O4 (Popescu and Brotea, 1989) to Subzone M1a. [Spezzaferri et al. 2018]
Last occurrence (top): within M1a subzone (22.44-22.96Ma, top in Aquitanian stage). Data source: Spezzaferri et al. 2018
First occurrence (base): within O4 zone (28.09-29.18Ma, base in Rupelian stage). Data source: Spezzaferri et al. 2018

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2018 - Olig Atlas chap.6 p.194

References:

Popescu, G. & Brotea, D. (1989). Genus Protentella (Foraminifera) in North Transylvania Oligcene. In, Petrescu, I. (ed.) The Oligocene from the Transylvanian Basin. Cluj-Napoca 255-260. gs

Spezzaferri, S. (1994). Planktonic foraminiferal biostratigraphy and taxonomy of the Oligocene and lower Miocene in the oceanic record. An overview. Palaeontographia Italica. 81: 1-187. gs

Spezzaferri, S., Coxall, H. K., Olsson, R. K. & Hemleben, C. (2018a). Taxonomy, biostratigraphy, and phylogeny of Oligocene Globigerina, Globigerinella, and Quiltyella n. gen. In, Wade, B. S. , Olsson, R. K. , Pearson, P. N. , Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 46: 179-215. gs

Srinivasan, M. S. & Kennett, J. P. (1974a). A planktonic foraminifer (Clavatorella) from the Pliocene. Journal of Foraminiferal Research. 4(2): 77-79. gs

van Eijden, A. J. M. & Smit, J. (1991). Eastern Indian Ocean Cretaceous and Paleogene quantitative biostratigraphy. Proceedings of the Ocean Drilling Program, Scientific Results. 121: 77-123. gs


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Globigerinella molinae compiled by the pforams@mikrotax project team viewed: 24-7-2019

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