Specimens which cannot be assigned to established species
| Daughter taxa (time control age-window is: 0-800Ma) | ||||
| | | Ventilabrella austinana | |
| | | Ventilabrella eggeri | |
| | | Ventilabrella ornatissima | |
| Ventilabrella sp. Specimens which cannot be assigned to established species | ||||
Taxonomy
Taxonomic discussion: A neotype for Ventilabrella eggeri Cushman (USNM No. 170308) from the Taylor Marl of Texas was designated by Martin (1972, p. 86).
Original description: Test in the early stages biserial, later with an increase in the number of chambers, but all in one plane, spread out tn a fan-shape; chambers globular; wall calcareous, perforate, smooth or variously ornamented; aperture in the biserial stage, single at the base of the inner margin, in the adult two apertures in each chamber, at opposite sides near the base in the median line. Upper Cretaceous.
Entries in the Catalog of original descriptions: Ventilabrella
Distinguishing features:
Parent taxon (Heterohelicidae): Aperture symmetrical, ranging from a low slit to a high arch at the base of the final chamber, becoming terminal in uniserial taxa.
This taxon: Similar to Planoglobulina but separate origin. Costae low and irregular.
Morphology: Test subtriangular to flabelliform in outline, laterally compressed, chambers globular to pyriform, those of early stage biserially arranged, later with chamber proliferation in the plane of biseriality, sutures distinct, depressed; wall calcareous, hyaline, perforate, surface with longitudinal discontinuous and somewhat irregular low costae; arched basal apertures on both margins of many chambers in the multiseriate stage, cameral flanges present, and these and the cameral ridges may be merged on the final series of chambers.
Geological Range:
Last occurrence (top): within Campanian Stage (72.05-83.64Ma, top in Campanian stage). Data source: Total of range of species in this database
First occurrence (base): within Turonian Stage (89.77-93.90Ma, base in Turonian stage). Data source: Total of range 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 Martin, S. E. (1972). Reexamination of the Upper Cretaceous planktonic foraminifera genera Planoglobulina and Ventilabrella Cushman. Journal of Foraminiferal Research. 2(2): 73-92. gsReferences:
 |
Ventilabrella compiled by the pforams@mikrotax project team viewed: 17-9-2021
Short stable page link: https://mikrotax.org/pforams/index.php?id=110566 Go to Archive.is to create a permanent copy of this page - citation notes |
Comments
(0)