The Pliocene Gastropoda (Mollusca) of Estepona, southern Spain. Part 27: Revision of the genera Alvania Risso, 1826 and Manzonia Brusina, 1870 (Rissoidae, Caenogastropoda)

In this paper the genera Alvania Risso, 1826 and Manzonia Brusina, 1870 (Rissoidae, Caenogastropoda) of the Upper Zanclean, Lower Pliocene of Estepona, southern Spain are reviewed. Twenty-eight species of Alvania are recorded, of which two are left in open nomenclature and nine are described as new: Alvania acutissimispira nov. sp., Alvania bicingulina nov. sp., Alvania cimicoiberica nov. sp., Alvania hispanica nov. sp., Alvania iberopliocenica nov. sp., Alvania lachrymiformis nov. sp., Alvania lobilloensis nov. sp., Alvania vandervalki nov. sp., Alvania veleriniana nov. sp. One species of the genus Manzonia is recorded. This almost doubles the previously known number of 15 rissoids from the Estepona deposits. Excluding species left in open nomenclature (2), this work highlights the highly endemic nature of the assemblages, with 11 (41%) found so far only in these assemblages. Fifteen (58%) are extinct.