Sphaeroidinella dehiscens is a rare tropical species (Fig. 37). It has clear preferences for tropical sea surface temperatures with low seasonality, and areas with average marine salinity. Its relation with summer salinity is narrow and may make this species a salinity indicator. The closer relation with summer conditions is also expressed in relations of relative abundances and the vertical temperature gradient, sea surface water density, and stratification. The close relation with the temperature at 200 m and the preference for areas of low stratification in summer, compared to average tropical conditions, suggests a deeper water habitat possibly related to the phase of reproduction of this species (Hemleben et al., 1989). See discussion section of this paper.