nmn

Schackoina


Classification: pf_mesozoic -> Schackoinidae -> Schackoina
Sister taxa: Leupoldina, Schackoina,
Daughter taxa: (blue => in age window 0-800Ma)



Specimens which cannot be assigned to established species

Taxonomy

Citation: Schackoina Thalmann 1932
Rank: Genus
Basionym: Siderolina cenomana
Type species: Siderolina cenomana Schacko, 1897

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: 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): 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 Albian Stage (100.50-112.95Ma, base in Albian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Dec 2017 - Plotting of Neptune data has been re-enabled on the Mesozoic pages following revision of the age-models in Neptune. The data is, however, still very sparse for the Early Cretaceous

References:

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


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Schackoina compiled by the pforams@mikrotax project team viewed: 1-10-2020

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Short stable page link: http://mikrotax.org/pforams/index.php?id=110519 Go to Archive.is to create a permanent copy of this page - citation notes



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