Guembelitria


Classification: pf_cenozoic -> microperforate -> Guembelitriidae -> Guembelitria
Sister taxa: Cassigerinelloita, Globoconusa, Guembelitria, Jenkinsina, Parvularugoglobigerina, Woodringina,
Daughter taxa (blue => in age window 0-300Ma)
As described by Cushman (1933) the test is small, triserial, and composed of globular chambers with strongly depressed sutures. The aperture is bordered by a distinct lip and often slightly asymmetric. When present, the appearance of apertural asymmetry results from infolding of the lip along one side of the aperture (as in Woodringina and Chiloguembelina). The wall structure is microperforate and the surface texture is often characterized by blunt pore-mounds--mounds that are marked by one or more pores.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Guembelitria Cushman, 1933
Rank: Genus
Type species: Guembelitria cretacea Cushman, 1933.
Synonyms: Chiloguembelitria Hofker, 1978:60.
Taxonomic discussion: Confusion remains over the taxonomic status of Chiloguembelitria, which Loeblich and Tappan (1988) retained as a valid genus and Kroon and Nederbragt (1990) suggested is a junior synonym of Guembelitria. This confusion is exacerbated by the absence of a designated holotype for Chiloguembelitria or its type species, Chiloguembelitria danica Hofker, 1978. Nonetheless, it appears that no morphological characters consistently distinguish Chiloguembelitria spp. from Guembelitria spp. The original description and illustration of C. danica Hofker, 1978, resembles Guembelitria cretacea Cushman, 1933, in its apertural characteristics and its consistent triseriality (Plate 63). The absence of distinct chiloguembelitriid characters indicates that, as suggested by Kroon and Nederbragt (1990), Chiloguembelitria danica Hofker, 1978, is a junior synonym of Guembelitria cretacea Cushman, 1933. [Olsson et al. 1999]

Catalog entries: Guembelitria;

Type images:

Distinguishing features: Test small and triserial. Aperture bordered by a distinct lip and often slightly asymmetric. Wall structure microperforate; surface texture of well-preserved specimens characterized by presence of pore-mounds.

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.

Description


Diagnostic characters: Test small and triserial. Aperture bordered by a distinct lip and often slightly asymmetric. Wall structure microperforate; surface texture of well-preserved specimens characterized by presence of pore-mounds.

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): in mid part of Danian Stage (48% up, 63.9Ma, in Danian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Maastrichtian Stage (36% up, 69.9Ma, in Maastrichtian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 79

References:

Cushman, J.A., (1933). Some new foraminiferal genera. Contributions from the Cushman Laboratory for Foraminiferal Research, 9(2): 32-38.

Hofker, J., (1978). Analysis of a large succession of samples through the Upper Maastrichtian and Lower Tertiary of Drill Hole 47.2, Shatsky Rise, Pacific, Deep Sea Drilling Project. Journal of Foraminiferal Research, 8(1): 46-75.

Kroon, D. & Nederbragt, A.J., (1990). Ecology and paleoecology of triserial planktic foraminifera. Marine Micropaleontology, 16: 25-38.

Loeblich, A.R., Jr. & Tappan, H., (1988). Foraminiferal Genera and Their Classification (Volume I-II). Van Nostrand Reinhold Co., New York, 1059 pp.

Olsson, R.K.; Hemleben, C.; Berggren, W.A. & Huber, B.T., (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Contributions to Paleobiology, 85. Smithsonian Institution Press, Washington, DC, 1-252 pp.


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Guembelitria compiled by the pforams@mikrotax project team viewed: 25-6-2018

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