Pseudohastigerina


Classification: pf_cenozoic -> Globanomalidae -> Pseudohastigerina
Sister taxa: Globanomalina, Muricohedbergella, Planoglobanomalina, Pseudohastigerina, Turborotalia,
Daughter taxa: - arranged by first occurrence (blue => in age window 0-300Ma)
Test small, much compressed, circular in umbilical view. Chambers globular, increase very slowly in size, Adult tests appear coarsely perforate.
Tests small, compressed, nearly circular in outline. Chambers globular, straight sutures, and rounded periphery in edge view. Aperture, high circular arch,with narrow, well-developed lip, frequently bipartite.
Test large, oval to quadrate; chambers much inflated, globular. Low chamber growth in final 3 chambers bipartite apertures common.
Test planispiral, smooth-walled test; chambers inflated globular, increase rapidly in size. Aperture, equatorial, single or bipartite, symmetrical.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Pseudohastigerina Banner and Blow, 1959
Rank: Genus
Type species: Nonion micrus Cole, 1927
Taxonomic discussion: Blow (1979) followed the concept of Pseudohastigerina set forth by Berggren and others (1967) who emended the genus to include tests with asymmetric to symmetric equatorial apertures. He drew (arbitrarily) the boundary between (Globorotalia = Globanomalina) and Pseudohastigerina “at the point where the primary aperture opens dorsally in direct continuation of the trace of the spiral suture” where “ a true planispiral coiling-mode can be said to have been attained” (p. 1060). This definition is followed here. In the transition from the ancestral Globanomalina luxorensis (Nakkady) to the descendent Pseudohastigerina wilcoxensis the aperture is, at first, equatorially asymmetrical but becomes symmetrical as symmetrical planispiral tests evolve. All later species in the Pseudohastigerina lineage have symmetrical planispiral tests. Another feature which Berggren and others (1967) first pointed out is the development of bipartite apertures in some individuals. Blow also described this feature and emended it to the definition of Pseudohastigerina.
[Olsson & Hemleben 2006]

Catalog entries: Pseudohastigerina;

Type images:

Distinguishing features: Planispiral.
Aperture equatorial, sometimes bipartite, may be asymmetrical.
Wall smooth, normally perforate.

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: The genus is characterized by a planispirally coiled, smooth-walled, normal perforate test, with an equatorial aperture which may vary from asymmetrical to symmetrical in position. The primary aperture may be singular or bipartite, arched openings bordered by a thin lip. [Olsson & Hemleben 2006]

Biogeography and Palaeobiology


Phylogenetic relations: Pseudohastigerina evolved from Globanomalina luxorensis at the base of Zone E2 by the development of a symmetrical umbilical aperture and slightly asymmetric to fully planispiral test. In Zone E1 (within the CIE in the Bass River Borehole, New Jersey) in large populations of typical G. luxorensis; rare morphotypes exhibit a tendency towards planispirality but never develop a fully umbilical aperture and a biumbilical test.
[Olsson & Hemleben 2006]

Pseudohastigerina evolved from Globanomalina luxorensis at the base of Zone E2 (Speijer and Samir, 1997; Berggren and Pearson, 2005; Olsson and Hemleben, 2006). [Pearson et al. 2018]

Most likely ancestor: Globanomalina - at confidence level 3 (out of 5). Data source: .

Biostratigraphic distribution

Geological Range:
Notes: Base of Zone E2 to the top of Zone O1 (lower Oligocene).
[Olsson & Hemleben 2006]
Last occurrence (top): in lower part of Rupelian Stage (31% up, 32.1Ma, in Rupelian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Ypresian Stage (2% up, 55.8Ma, in Ypresian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Olsson & Hemleben 2006 - Eocene Atlas, chap. 14, p. 420

References:

Banner, F.T. & Blow, W.H., (1959). The classification and stratigraphical distribution of the Globigerinaceae. Palaeontology, 2(1): 1-27.

Berggren, W.A. & Pearson, P.N., (2005). A revised tropical to subtropical Paleogene planktonic foraminiferal zonation. Journal of Foraminiferal Research.

Blow, W.H., (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea), 2. E. J. Brill, Leiden, 1413 pp.

Cole, W.S., (1927). A foraminiferal fauna from the Guayabal formation in Mexico. Bulletins of American Paleontology, 14(51): 1-36.

Miller, K.G.; Aubry, M.-P.; Khan, M.J.; Melillo, A.J.; Kent, D.V. & Berggren, W.A., (1985). Oligocene–Miocene biostratigraphy, magnetostratigraphy, and isotopic stratigraphy of the western North Atlantic. Geology, 13: 257-261.

Molina, E.; Arenillas, I. & Pardo, A., (1999). High resolution planktic biostratigraphy and correlation across the Paleocene/Eocene boundary in the Tethys. Bulletin Société Géologique de France, 170: 521-530.

Olsson, R.K. & Hemleben, C., (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Globanomalina, Planoglobanomalina n. gen and Pseudohastigerina. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera. Cushman Foundation Special Publication. 41 Allen Press, Lawrence, Kansas, pp. 413-432.

Olsson, R.K. & Hemleben, C., (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Globanomalina, Planoglobanomalina n. gen and Pseudohastigerina. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera. Cushman Foundation Special Publication. 41 Allen Press, Lawrence, Kansas, pp. 413-432.

Pearson, P.N.; Olsson, R.K.; Spezzaferri, S. & Leckie, R.M., (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene Globanomalinidae (Turborotalia and Pseudohastigerina). In: Wade, B.S. et al. (Editors), Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research Special Pulbication. 46, pp. 403-415.

Speijer, R.P. & Samir, A.M., (1997). Globanomalina luxorensis, a Tethyan biostratigraphic marker of latest Paleocene global events. Micropaleontology, 43: 51-62.


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Pseudohastigerina compiled by the pforams@mikrotax project team viewed: 15-12-2018

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