pforams@mikrotax - Globigerinella megaperta

Globigerinella megaperta

Classification: pf_cenozoic -> Globigerinidae -> Globigerinella -> Globigerinella megaperta
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.

Olig Atlas pl06-05 13-15.JPG
Olig Atlas pl06-05 08-10.JPG
Olig Atlas pl06-05 11-12.JPG

Taxonomy

Citation: Globigerinella megaperta Rögl, 1994

Rank: species

Synonyms:

Globigerinella megaperta Rögl, 1994:142, pl. 3, figs. 7-13, pl. 4, fig. 6 [mid-Oligocene, lower Eggerian, Austrian Molasse Basin].—Cicha and others, 1998:101, pl. 37, figs. 10-13 [mid-Oligocene, lower Eggerian, Austrian Molasse Basin].—Székely and Filipescu, 2016:490, pl. 2, figs. 8a-c [upper Oligocene, Chattian, Transylvanian Basin, Romania].
‘Giant Globigerina ciperoensis’ Ujetz and Wernli 1994:200-201 (partim), pl. 1, figs. 2a-b [lower Oligocene Zone P20, Haute Savoie, France] (not figs. 1a-b = Globigerinella wagneri).

Taxonomic discussion:

Globigerinella megaperta and closely related G. wagneri are unique to the Paratethys and possess a globigerinid wall of high pore porosity and wall structure of coalescing ridges with evidence of spine collars, as is diagnostic of the bulloides-type wall. Based on these features, together with the extraumbilical-to equatorial position of the aperture, they are placed in Globigerinella, although it is important to point out that they do not have the typical bulloides-type wall of pore diameters less than 1µm. Some specimens may display a sac-like last chamber and/or aberrant chambers. This also co-occurs in G. wagneri (Rögl, 1994). [Spezzaferri et al. 2018]

Catalog entries: Globigerinella megaperta

Type images:

holotype: G. megaperta
holotype: G. megaperta
paratype: G. megaperta

Distinguishing features: Aperture unusually open and highly arched, formed from final 4 chambers; initial coiling streptospiral,

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

Wall type: Spinose; spines are supported by spine collars, which coalesce to form ridges. Pore concentrations range from around 85-90 pores/50 μm² test surface area and pore diameters range from around 2-3.5 μm.

Morphology: low trochospiral to pseudoplanispiral, inner coil depressed, lobulate in outline with depressed and straight sutures on both sides. Eleven chambers are arranged in 2½ whorls, the chambers of the inner whorls are very small, the 5-6 globular chambers of the last whorl increase rapidly in size, the last 4 chambers open into the large and deep umbilicus. The aperture is a very large and high asymmetrical arch interiomarginal becoming marginal, and bordered by a thick rim. [Spezzaferri et al. 2018]

Size: Diameter of the holotype from 0.45 mm. [Spezzaferri et al. 2018]

Character matrix

test outline:	Lobate	chamber arrangement:	Pseudoplanispiral	edge view:	Equally biconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Globular	coiling axis:	Very low	periphery:	N/A	aperture border:	N/A
umb chbr shape:	Globular	umbilicus:	Wide	periph margin shape:	Broadly rounded	accessory apertures:	None
spiral sutures:	Strongly depressed	umb depth:	Deep	wall texture:	Cancellate	shell porosity:	Macroperforate: >2.5µm
umbilical or test sutures:	Strongly depressed	final-whorl chambers:	5.0-6.0	N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution: This species has been found only in Haute Savoie and Central Paratethys. [Spezzaferri et al. 2018]

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

Phylogenetic relations: Globigerinella megaperta evolved from G. wagneri in lower Oligocene Zone O3 and can be considered as an end member of a unique Paratethys globigerinellid lineage. [Spezzaferri et al. 2018]

Most likely ancestor: Globigerinella wagneri - at confidence level 3 (out of 5). Data source: Spezzaferri et al. 2018.

Biostratigraphic distribution

Geological Range:
Notes: This species was described from the late Rupelian and Chattian of the Austrian Molasse Basin (Rögl, 1994; Cicha and others, 1998) corresponding to the interval spanning Zone O4 to O5. The specimens documented by Ujetz and Wernli (1994) from Zone P20 in Haute Savoie (French Alps) allow the extension of its range down to Zone O3. [Spezzaferri et al. 2018]
Last occurrence (top): within O5 zone (26.93-28.09Ma, top in Chattian stage). Data source: Spezzaferri et al. 2018
First occurrence (base): within O3 zone (29.18-30.28Ma, base in Rupelian stage). Data source: Spezzaferri et al. 2018

Plot of occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
(NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Globigerinella

Primary source for this page: Spezzaferri et al. 2018 - Olig Atlas chap.6 p.192

References:

Cicha, I., Rögl, F., Rupp, C. & Ctyroká, J. (1998). Oligocene-Miocene foraminifera of the central Paratethys. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft. 549: 1-325. gs

Rögl, F. (1994). Globigerina ciperoensis (Foraminiferida) in the Oligocene and Miocene of the central Paratethys. Annalen des Naturhistorischen Museums in Wien. 96A: 133-159. gs V O

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(Chap 6): 179-214. gs V O

Szekely, S. -F. & Filipescu, S. (2016). Biostratigraphy and paleoenvironments of the Late Oligocene in the north-western Transylvanian Basin revealed by the foraminifera assemblages. Palaeogeography Palaeoclimatology Palaeoecology. 449: 484-509. gs

Ujetz, B. & Wernli, R. (1994). “Globigerina ciperoensis”, atypically giant planktonic foraminifers from the Oligocene of the Haute-Savoie, France. Annalen des Naturhistorischen Museums in Wien. 96A: , , 199-207. gs

Globigerinella megaperta compiled by the pforams@mikrotax project team viewed: 18-4-2021

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Short stable page link: https://mikrotax.org/pforams/index.php?id=104351 Go to Archive.is to create a permanent copy of this page - citation notes

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