Specimens which cannot be assigned to established species
| Daughter taxa (time control age-window is: 0-800Ma) | ||||
| | | Schackoina bicornis | |
| | | Schackoina cenomana | |
| | | Schackoina multispinata | |
| Schackoina sp. Specimens which cannot be assigned to established species | ||||
Taxonomy
Original description: Da verschiedene Arten der Gattung Hantkenina sich als ausgezeichnete Leitformen zur Unterscheidung eozäner von oligozänen Schichten erwiesen haben, sei an dieser Stelle auf die stratigraphische Verbreitung der einzelnen bisher bekannt gewordenen Vertreter hingewiesen.
1. Kreide. Die wohl am primitivsten ausgebildeten Hantkenina- Arten sind die beiden einzigen bisher aus kretazischen Schichten bekannt gewordenen:
Hantkenina cenomana (Schacko 1896) und
Hantkenina multispinata Cushman el Wickenden 1930.
....
Diese beiden primitiven Hantkenina-Arten der Kreide weichen in mehrfacher Beziehung vom Genotyp aus dem Obereozän ab (geringere Kammerzahl bei H. cenomana; abweichender polyhedrischer Schalenbau, primitive schwach-bogenförmig geformte Mündung sowie zahlreichere unregelmässig-angeordnete tubulösc „Stacheln" bei H. multispinata). Diese Unterscheidungsmerkmale scheinen es zu rechtfertigen, die kretazischen Arten einem neuen Subgenus Schackoina zuzuweisen, mit Subgenotyp: Hantkenina (Schackoina) cenomana (Schacko 1896).
Entries in the Catalog of original descriptions: Schackoina
Distinguishing features:
Parent taxon (Schackoinidae): Test trochospiral to nearly planispiral, chambers with one or more hollow tubulospines; aperture equatorial and may have broad lip.
This taxon: Test small, with early low trochospiral stage, later nearly planispiral, early chambers globular, later ones radially elongate and laterally compressed, one or more elongate tubulospines extending from the midline of each chamber on the periphery, biumbilicate, sutures depressed; wall calcareous, very finely perforate, optically radial, surface slightly hispid; aperture a low interiomarginal and equatorial arch bordered by a distinct lip, part of the lateral extensions of the aperture into the umbilicus may remain as relict apertures.
Geological Range:
Last occurrence (top): at top of G. ventricosa zone (100% up, 76.2Ma, in Campanian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within P. appenninica zone (100.50-101.92Ma, 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. gsReferences:
 |
Schackoina compiled by the pforams@mikrotax project team viewed: 17-1-2025
Short stable page link: https://mikrotax.org/pforams/index.php?id=110519 Go to Archive.is to create a permanent copy of this page - citation notes |
This policy contains information about your privacy. By posting, you are declaring that you understand this policy:
This policy is subject to change at any time and without notice.
These terms and conditions contain rules about posting comments. By submitting a comment, you are declaring that you agree with these rules:
Failure to comply with these rules may result in being banned from submitting further comments.
These terms and conditions are subject to change at any time and without notice.
Comments