Non-spinose, trochospiral, with 3-4 chambers in last whorl, spiral side flat, chambers on apertural side subspherical, aperture slit-like reaching from periphery towards the umbilicus. Wall structure of different phases, observed only in this species and in Pulleniatina obliquiloculata. Growth of wall begins with bilamellar construction followed by secretion of additional calcite layers on outer surface of test, including formation of pustules over entire surface. When individual migrates to deeper water (below the thermocline) calcite crust may form, subsequently smoothed by thin calcite veneer, thus giving test shiny reflective appearance when viewed under binocular microscope. No keel.
Ref.: Huang (1981), Ganssen (1983), Malmgren and Kennett (1983), Hemleben et al. (1985), Ravelo and Fairbanks (1995), Rohling et al. (1995).
Distribution: Often a dominant component in temperate waters (up to 33% of all foraminifers; see Boltovskoy et al., 1996), but also present in cold as well as warm areas, preferring the former. In the eastern South Atlantic it peaks around 40°S. In the western South Atlantic and in the eastern North Atlantic it is abundant in spring. Its reproduction is closely related to the lunar cycle (Schiebel and Hemleben, unpublished data). It feeds on phytoplankton available in the photic zone.