Original description: Diagnosis: Trochospiral test with more convex umbilical side, with four chambers in the final whorl and strongly overlapping chambers. Periphery with one distinct keel. Sutures sigmoidal.
Description of the test: Trochospirally coiled test with four chambers in the final whorl. Chambers are strongly overlapping. The umbilical side of the test rather convex, the spiral one concave or flattened. Periphery with one distinct keel. The aperture interiomarginal, accessory apertures with lips at the adumbilical portions of the last chambers. Surface smooth.
Entries in the Catalog of original descriptions: Globotruncana sigmoconcavata
Last occurrence (top): within Dicarinella asymetrica zone (84.19-86.71Ma, top in Santonian stage). Data source:
First occurrence (base): within Marginotruncana schneegansi zone (89.91-92.56Ma, base in Turonian stage). Data source:
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
Marginotruncana sigmoconcavata compiled by the pforams@mikrotax project team viewed: 4-6-2020
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