Forms. According to Amédro (1992), the primitive forms are thick and involute, with rounded ribs and narrower interspaces, such as S. perinflata Breistroffer. Then come less involute, less thick forms, with sharper and more widely spaced ribs, for example S. flava Casey. The most recent species, such as S. dutempleana (d'Orbigny), have a hexagonal whorl section, a flattened venter, and, according to Saveliev (1992), ribs with a posterior slope steeper than the anterior one. Saveliev (1973) created three very practical subgenera which we use in our sheets, with a slightly different breakdown than that of Amédro: Globosonneratia for globular forms, Sonneratia stricto sensu for those with a hexagonal section, and Eosonneratia for all the others. The whorl section of the latter subgenus varies from relatively thick, like E. kitchni, to compressed, like E. titovi.
Distribution. This fairly rare genus occurs in Europe in the kitchini, floridum, and puzosianus zones of Amédro's (1992) phyletic zonation for the Anglo-Paris Basin. In France, it has been found in condensed levels, in the Pas-de-Calais, Ardennes, Aube, Meuse, Yonne, Isère, and Haute-Savoie departments. In Transcaspia (the region east of the Caspian Sea), it is met from the globulosa subzone to the puzosianus subzone in Saveliev's zonation for Mangystau.