Specimens which cannot be assigned to established species
| Daughter taxa (time control age-window is: 0-800Ma) | ||||
| | | Gansserina gansseri | |
| | | Gansserina repanda | |
| | | Gansserina wiedenmayeri | |
| Gansserina sp. Specimens which cannot be assigned to established species | ||||
Taxonomy
Original description: Test.- A very low trochospire with a flat spiral side and a convex umbilical side. Primary aperture umbilical. Umbilicus about â…“ of the maximum diameter. Umbilical system composed of portici bordering the succcssive apertures, leaving proximal accessory apertures, and sometimes composed of tegilla towards the end of the whorl. Chamber profile with one or two moderately developed keels, the keel on the umbiilical side generally less developed or reduced to a row of pustules parallel to the keel situated on the spiral side, or absent. Chamber surface pustulose on the umbilical side, except sometimes towards the end of the last whorl; slightly pustulose on the spiral side; initial chumbers typically globular on the spiral side. Sutures depressed, more or less radial on tbe umbilical side; curved and variably raised on the spiral side. Peripheral outline subcircular, slightly lobate.
Entries in the Catalog of original descriptions: Gansserina
Distinguishing features:
Parent taxon (Globotruncanidae): Test trochospiral, chambers angular, periphery truncate or carinate; primary aperture umbilical, covered by a spiral system of tegilla that is provided with accessory intralaminal and infralaminal apertures.
This taxon: Test in a low to flat trochospiral coil, spiral side flat, umbilical side convex with wide umbilicus that is occupied by portici and tegilla, early chambers globular, later ones rhomboidal in section, sutures strongly curved, elevated and oblique on the spiral side, radial and depressed on the umbilical side, distinct peripheral keel on the edge of the spiral side, the umbilical peripheral margin with a less developed second keel consisting only of a row of pustules or this may be absent, peripheral outline entire to weakly lobulate; wall calcareous, perforate, surface pustulose, particularly on the umbilical side of the test; primary aperture interiomarginal, umbilical, and bordered by a wide porticus, those of successive chambers remaining as accessory apertures, and portici may fuse into tegilla in the later stage.
Geological Range:
Last occurrence (top): at top of A. mayaroensis zone (100% up, 67.6Ma, in Maastrichtian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within G. elevata zone (79.33-83.65Ma, base in Campanian 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 Robaszynski, F., Caron, M., Gonzales Donoso, J. M., Wonders, A. A. H. & the European Working Group on Planktonic Foraminifera (1984). Atlas of Late Cretaceous globotruncanids. Revue de Micropaléontologie. 26(3-4): 145-305. gsReferences:
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Gansserina compiled by the pforams@mikrotax project team viewed: 23-1-2025
Short stable page link: https://mikrotax.org/pforams/index.php?id=110111 Go to Archive.is to create a permanent copy of this page - citation notes |
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