pforams@mikrotax - Planomalina pforams@mikrotax - Planomalina


Classification: pf_mesozoic -> Planomalinidae -> Planomalina
Sister taxa: Planomalina, Pseudoplanomalina
Daughter taxa (time control age-window is: 0-800Ma)
Planomalina buxtorfi

Planomalina praebuxtorfi

Planomalina pulchella

Planomalina sp.
Specimens which cannot be assigned to established species


Citation: Planomalina Loeblich and Tappan 1946
taxonomic rank: Genus
Type species: Planomalina apsidostroba Loeblich and Tappan, 1946 = Planulina buxtorfi Gandolfi, 1942
Taxonomic discussion: Although Robaszynski and Caron (1979, p. 43) state that the stratigraphic range is Upper Albian ("Vraconnian"), the type locality of P. apsidostroba (type species of the genus but a synonym of P. buxtorfi) was in the Main Street Limestone in Johnson Co., Texas, a formation containing the ammonite Plesioturrilites brazoensis (Roemer), whose first occurrence now is regarded as marking the Albian-Cenomanian boundary. P. buxtorfi also occurs in the underlying Paw Paw Formation of the Fort Worth region of Texas (that we also regard as lowest Cenomanian); furthermore it has been recorded (as P. almadenensis Cushman and Todd) in the Cenomanian of California, as well as in the upper Albian Weno and Georgetown Formations of central Texas.

Original description: Test free, planispiral, partially evolute, so that earlier coils may be seen on both sides of the biumbilicate test; chambers numerous; sutures may be limbate; wall calcareous, coarsely perforate; apertnuor peripheral, an arch at the base of the aptertural face of the last-formed chamber, with a distinct lip. 

Entries in the Catalog of original descriptions: Planomalina

Distinguishing features:
Parent taxon (Planomalinidae): Test planispiral, biumbilicate, periphery carinate, sutures strongly arched; aperture a low equatorial opening.
This taxon: Test planispiral, partly evolute, biumbilicate, about eight to ten chambers in the final whorl, sutures broadly curved, thickened, elevated and nodose, peripheral outline lobulate, peripheral angle carinate; wall calcareous, finely perforate, radial in structure, ornamented by the thickened and nodose sutures and peripheral keel; aperture a basal equatorial arch with bordering lip, the opening extending to either side, where part of previous apertures and the bordering lip may remain exposed as relict apertures as the new chambers are added.

Geological Range:
Last occurrence (top): at top of P. appenninica zone (100% up, 100.5Ma, in Albian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within P. ticinensis zone (101.92-103.94Ma, base in Albian stage). Data source: Total of ranges of species in this database

Plot of range and occurrence data:


Loeblich, A. R. & Tappan, H. (1988). Foraminiferal Genera and Their Classification (Volume I-II). Van Nostrand Reinhold Co., New York. 1-1059. gs


Planomalina compiled by the pforams@mikrotax project team viewed: 14-4-2024

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