Diagnosis
provided by World Register of Marine Species
Test discoidal to lenticular; dimorphism prominent, microspheric early stage enrolled or biserial, megalospheric generation with distinctive embryonic stage enclosed in a thicker wall, the early coiled or bilocular embryo followed by somewhat larger periembryonal chambers, equatorial and lateral chambers may be differentiated or indistinguishable, chambers of median layer may be subdivided into secondary chamberlets; wall of perforate, hyaline, optically radial calcite; openings present between chambers in geologically older forms, replaced by distinct stolons in advanced forms, no canal system. U. Cretaceous (Santonian) to U. Eocene. (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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