''Gansserina'' is a genus of planktonic

foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and ot ...

, included in the globigerinid family Globotruncanidae,Gansserina
World Foraminifera Database, accessed 3 December 2018 that had a fairly wide distribution in the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

(

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...

). The type species is ''Gansserina gansseri''. The test of ''Gansserina'' is coiled in a low to flat trochospiral. The spiral side is flat, with curved, raised and oblique sutures. The umbilical side is convex with radial depressed sutures and a wide umbilicus containing portici (asymmetrical apertural flaps) and tegilla (umbilical coverings). A distinct peripheral keel runs along the edge of the spiral side while the periphery on the umbilical side may have an incompletely developed keel formed by pustules. Early chambers are globular, later ones rhomboidal in section. The wall is calcareous, perforate and pustulate, especially on the umbilical side. The primary aperture is interiomarginal, bordered by a wide porticus (flap). ''Gansserina gansseri'', based on stable isotope study (C₁₃ and O₁₈) of specimens from Lower Maastrichtian marine sediments, is thought to have lived at intermediate depths, within the paleothermocline.

References

Alfred R. Loeblich Jr Alfred R. Loeblich Jr (1914–1994) was an American micropaleontologist. He was married to Helen Niña Tappan Loeblich and the two co-authored a number of important works on the Foraminifera and related organisms. Biography Alfred R. Loeblich Jr ...

and

Helen Tappan Helen may refer to: People * Helen of Troy, in Greek mythology, the most beautiful woman in the world * Helen (actress) (born 1938), Indian actress * Helen (given name), a given name (including a list of people with the name) Places * Helen, G ...

, 1964. Sarcodina Chiefly "Thecamoebians" and Foraminiferida;

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and co ...

, Part C Protista 2. Geological Society of America and University of Kansas Press.
Loeblich, A.R and H. Tappan, 1988. Forminiferal Genera and their Classification
* Sigal Abramovich, ''et al'' 2003. Characterization of late Campanian and Maastrichtian planktonic foraminiferal depth habitats and vital activities based on stable isotopes. Palaeogeography, Palaeoclimatology, Palaeoecology 202 (2003) 1-29 {{Taxonbar, from=Q6438554 Rotaliida genera Globigerinina Fossil taxa described in 1951