Globigerinella obesa


Classification: pf_cenozoic -> Globigerinidae -> Globigerinella -> Globigerinella obesa
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 obesa (Bolli, 1957)
Rank: species
Basionym: Globorotalia obesa Bolli, 1957
Synonyms:
Taxonomic discussion:

Globigerinella obesa was initially included in the genus Globorotalia. It is now recognized as the first species of Globigerinella. SEMs of the holotype of Blow’s Globigerina praebulloides and the paratype USNM 625702A show that they have a bulloides-type wall texture, but chamber architecture very similar to G. obesa, e.g., umbilical-extraumbilical primary aperture therefore, praebulloides is here considered a junior synonym of Globigerinella obesa Bolli (Pl. 6.8, Figs. 4-6). [Spezzaferri et al. 2018]

Catalog entries: Globorotalia obesa, Globigerina praebulloides

Type images:

Distinguishing features: Low trochospiral lobulate test, 4 chambers in the last whorl, extraumbilical to equatorial aperture; bulloides-type wall texture.

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:

Globigerinella obesa is characterized by low trochospiral lobulate test, 4 chambers in the last whorl, extraumbilical to equatorial aperture and a bulloides-type wall texture. It differs from G. archaeobulloides, from which it evolved, and G. bulloides by having an umbilical-extraumbilical aperture tending toward the peripheral margin and a somewhat inflated final chamber. It differs from G. praesiphonifera by the more enrolled coiling, having 4 chambers in the last whorl instead of 5 in G. praesiphonifera, lesser tendency towards planispirality and a less lobulate outline. [Spezzaferri et al. 2018]


Wall type: Spinose, spines are supported by spine collars which coalesce to form ridges. Pore concentrations average 62 pores/50 μm2 test surface area and pore diameters average 2.5 μm.

Test morphology: Test very low trochospiral, consisting of 2-2½ whorls, lobulate in outline, chambers globular; in spiral view 4 globular, slightly embracing chambers in ultimate whorl, increasing rapidly in size, sutures moderately depressed, straight; in umbilical view 4 globular, slightly embracing chambers, increasing rapidly in size, sutures moderately depressed, straight, umbilicus small, open, enclosed by surrounding chambers, aperture umbilical-extraumbilical, a low arch sometimes bordered by an imperforate rim; in edge view chambers globular in shape, slightly embracing. [Spezzaferri et al. 2018]

Size: Maximum diameter of holotype 0.5 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:Thin 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:4.0-4.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Identified in low to middle latitudes. [Spezzaferri et al. 2018]

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

Phylogenetic relations: Globigerinella obesa evolved from Globigerina archaeobulloides n. sp. in the lower Oligocene Zone O1 and gave rise to G. praesiphonifera in the mid-Oligocene Zone O4. [Spezzaferri et al. 2018]

Most likely ancestor: Globigerina archaeobulloides - at confidence level 3 (out of 5). Data source: Spezzaferri et al. 2018.
Likely descendants: Globigerinella praesiphonifera; Globigerinella pseudobesa; Globigerinella roeglina; Globigerinella wagneri;

Biostratigraphic distribution

Geological Range:
Notes: Lower Oligocene Zone O1 (Plate 6.1, Figs. 14-17) to the lower Pliocene (Kennett and Srinivasan, 1983). [Spezzaferri et al. 2018]. NB Kennett & Srinivasan (1983) record the range as extending to the recent but the specimen they illustrate is from the Early Pliocene. [editor's comment - JRY 2018]
Last occurrence (top): within Early Pliocene Sub-Epoch (3.60-5.33Ma, top in Zanclean stage). Data source: Spezzaferri et al. 2018
First occurrence (base): within O1 zone (32.10-33.90Ma, base in Priabonian 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.198

References:

Beldean, C., Filipescu, S. & Bălc, R. (2012). P and biostratigraphic data for the early Miocene of the north-western Transylvanian basin based on planktoqnic foraminifera. Carpathian Journal of Earth and Environmental Sciences. 7: 171-184. gs

Blow, W. H. (1959). Age, correlation, and biostratigraphy of the upper Tocuyo (San Lorenzo) and Pozon Formations, eastern Falcon, Venezuela. Bulletins of American Paleontology. 39(178): 67-251. gs

Bolli, H. M. (1957b). Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I. In, Loeblich, A. R. , Jr. , Tappan, H. , Beckmann, J. P. , Bolli, H. M. , Montanaro Gallitelli & E. Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 97-123. gs

Jenkins, D. G. (1971). New Zealand Cenozoic Planktonic Foraminifera. New Zealand Geological Survey, Paleontological Bulletin. 42: 1-278. gs

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

Molina, E. (1979). Oligoceno-Mioceno inferior por media de foraminiferos planctonicos en el sector central de las Cordilleraa Beticas Espana (Tesis doctoral). . 1-342. gs

Pearson, P. N. & Wade, B. S. (2009). Taxonomy and stable isotope paleoecology of well-preserved planktonic foraminifera from the uppermost Oligocene of Trinidad. Journal of Foraminiferal Research. 39: 191-217. gs

Spezzaferri, S. & Premoli Silva, I. (1991). Oligocene planktonic foraminiferal biostratigraphy and paleoclimatic interpretation from Hole 538A, DSDP Leg 77, Gulf of Mexico. Palaeogeography, Palaeoclimatology, Palaeoecology. 83: 217-263. 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

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


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Globigerinella obesa compiled by the pforams@mikrotax project team viewed: 22-8-2019

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