Biodiversité et biogéographie chez les Cavoliniidae (Mollusca, Gastropoda, Opisthobranchia, Euthecosomata). Régions faunistiques marines

Several Cavoliniidae new to science are described: Cavolinia gibboides n. sp. (gibbosa group), Diacria gracilis n. sp. (trispinosa group), Creseis conica falciformis n. ssp., Creseis virgula frontieri n. ssp., Cavolinia longicostata n. sp., Cavolinia pachysoma n. sp., Cavolinia labiata robusta n. ssp. (inflexa group), Clio convexa cyphosa n. ssp. (pyramidata group) and Diacria trispinosa heterocolorata n. ssp., the last five collected in recent sediments. Several subspecies take the species level: Cuvierina urceolaris (Mörch, 1905) (synonym Cuvierina columnella urceolaris), Cuvierina columnella (Rang, 1827) (synonym Cuvierina columnella columnella), Cavolinia plana (Meisenheimer, 1905) (synonym Cavolinia gibbosa plana), Cavolinia flava (d’Orbigny, 1836) (synonym Cavolinia gibbosa flava), Cavolinia gibbosa (d’Orbigny, 1836) (synonym Cavolinia gibbosa gibbosa), Cavolinia labiata (d’Orbigny, 1836) (synonym Cavolinia inflexa labiata). Cuvierina columnella forma atlantica is redescribed and renamed Cuvierina spoeli n. sp. At the structural level, the most widespread is the clinal variation, but geographically isolated species are also recorded for example in the Mediterranean, the Red Sea and the Mozambique Channel. The problem of the primary phenotypes is evaluated on the basis of the characters of the recent species and sometimes of their fossil ancestors. The distribution of the different taxa induces to split the Indo-Pacific Cavoliniidae in two entities: the western Indo-Pacific and the eastern Pacific ones, and to point out some faunistic similarities between the Atlantic Ocean and the eastern Pacific Ocean confirming that relations existed between those two oceans until the Pliocene, before the emergence of the Isthmus of Panama. The Mediterranean and the Red seas are appendices of the Atlantic and Indian oceans but they both represent entities characterized by endemic species and Tethysian relicts along with original forms or biological species. Despite their proximity, and the recent artificial connections, the Mediterranean and the Red seas have different faunistic caracteristics: no lessepsian migration has been recorded for Euthecosomata.