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Pseudoguembelina palpebra


Classification: pf_mesozoic -> Heterohelicidae -> Pseudoguembelina -> Pseudoguembelina palpebra
Sister taxa: P. costellifera, P. costulata, P. excolata, P. hariaensis, P. kempensis, P. palpebra, P. semicostata, P. sp.

Taxonomy

Citation: Pseudoguembelina palpebra Bronnimann and Brown 1953
Rank: Species
Basionym: Pseudoguembelina palpebra
Synonyms: Pseudoguembelina cornuta; Pseudoguembelina leroyi; Pseudoguembelina polypleura
Taxonomic discussion: The shape of the terminal chamber is variable. Some specimens of Psg. palpebra have a small globular bi-apertured final chamber; such specimens usually lack accessory apertures. [copied from Chronos database]

Type images:

Original description: "This medium-sized test is composed of 5-8 pairs of chambers which rapidly increase in size in the direction of growth. The pointed initial end consists of as many as 5 pairs of small chambers. In later development the chambers are considerably larger and more inflated. However, in many specimens the ultimate pair of chambers displays strong lateral compression. The pointed initial stage is entire or unlobated in lateral view; the later development is distinctly lobated. The sutures are flush in the early stage, and impressed in the later stage. Surface markings are indistinct or absent in the early stage; later well-developed longitudinal striae parallel the contour of the chambers. In the ultimate pair of chambers these striae are more numerous but somewhat fainter. The principal aperture is a relatively large semilunar opening at the base of the inner margin of the ultimate chamber. It is bordered by a liplike rim. Relatively large accessory apertures are developed in the later stage. Each chamber in the later stage possesses 2 conspicuous accessory apertures, one on each side, directly over the crest of the subjacent chamber. The flaps of the accessory apertures resemble small eyelids. Small papillae form a granular area above the flaps and near the median line."

Entries in the Catalog of original descriptions: Pseudoguembelina palpebra, Pseudoguembelina cornuta, Pseudoguembelina leroyi, Pseudoguembelina polypleura

Geological Range:
Last occurrence (top): within A. mayaroensis zone (67.30-69.18Ma, top in Maastrichtian stage). Data source: [copied from Chronos database]
First occurrence (base): at base of P. palepebra (0% up, 0Ma, in stage). Data source: zonal marker (from Timescale Creator)

Plot of range and occurrence data:

Character matrix

test outline:Subtriangularchamber arrangement:Biserialedge view:Equally biconvexaperture:Interiomarginal
sp chamber shape:Inflatedcoiling axis:N/Aperiphery:N/Aaperture border:Thick flange
umb chbr shape:Inflatedumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:Sutural
spiral sutures:N/Aumb depth:Deepwall texture:Coarsely muricateshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:2.0-2.0 N.B. These characters are used for advanced search. N/A - not applicable

References:

Brönnimann, P. & Brown, N. K. (1953). Observations on some planktonic Heterohelicidae from the Upper Cretaceous of Cuba. Contributions from the Cushman Foundation for Foraminiferal Research. 4(4): 150-156. gs V O

Nederbragt, A. J. (1991). Late Cretaceous biostratigraphy and development of Heterohelicidae (planktic foraminifera). Micropaleontology. 37: 329-372. gs

Pessagno, E. A. (1967). Upper Cretaceous planktonic foraminifera from the western Gulf Coastal Plain. Palaeontographica Americana. 5: 245-445. gs V O

Smith, C. C. & Pessagno, E. A. (1973). Planktonic foraminifera and stratigraphy of the Corsicana formation (Maestrichtian) North-central Texas. Cushman Foundation for Foraminiferal Research, Special Publication. 12: 1-67. gs


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Pseudoguembelina palpebra compiled by the pforams@mikrotax project team viewed: 6-12-2020

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Short stable page link: http://mikrotax.org/pforams/index.php?id=110455 Go to Archive.is to create a permanent copy of this page - citation notes



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