Diagnosis
provided by World Register of Marine Species
Test planispiral, at least in the adult, involute, biumbilicate, with narrow depressed umbilici, about eight to ten chambers per whorl, enlarging gradually as added, chamber walls bend inward posteriorly and fuse to the preceding septal face, forming narrow intercameral lacunae along the septa, intercameral sutures radial, gently curved, deeply incised near the umbilicus, no rotaliid septa] flaps or toothplates, no septal or radial canals, and no retral processes or fossettes, periphery broadly rounded; wall calcareous, perforate, of optically radial but morphologically granular calcite, tubercles prominently developed around the aperture, along the intercameral sutures and over the umbilicus; primary aperture a low and symmetrical interiomarginal arch but may be obscured by abundant surface pustules, intercameral foramen similar but may be enlarged by resorption, internally an interiomarginal supplementary aperture connects the intercameral lacunae to the following chamber lumen, or supplementary areal apertures may connect the lacunae to both preceding and following chambers. U. Pliocene (Astian) to Holocene; England; Wales; Ireland; North Sea; France; Netherlands; Denmark; Norway; Germany; Turkey; Siberia; USA: off New York, Massachusetts. (Loeblich & Tappan, 1987, Foraminiferal Genera and Their Classification)
Loeblich, A. R.; Tappan, H. (1987). Foraminiferal Genera and their Classification. Van Nostrand Reinhold Company, New York. 970pp.
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