CONICET | Buscador de Institutos y Recursos Humanos

This systematic review synthesizes our updated knowledge of 33 species and subspecies of Stylomatophoran gastropods, which belong to the genera Gastrocopta, Succinea, Radiodiscus, Retidiscus, Rotadiscus, Cecilioides,Austroborus, Megalobulimus, Bulimulus, Discoleus, Naesiotus, Plagiodontes, Spixia, Scolodonta, Miradiscops and Epiphragmophora. We provide published and unpublished records of the terrestrial molluscan taxa and a critical review, including data from the most important collections deposited in institutions from Argentina and abroad. All the taxa described have modern representatives; only two, Succinea rosariensis and Scolodonta argentina, still require confirmation regarding their taxonomic validity. The genera with confirmed older than Quaternary records are Austroborus, Megalobulimus, Radiodiscus, Rotadiscus and Succinea, which occur since the Paleogene. Regarding the modern geographical distribution, well known records involve part of Argentina (Subtropical and Pampean Dominia of the Guayanian-Brazilian Subregion and the Central Dominion of the Andean Subregion, both in the Neotropical Region). The best-known fraction of the fossil molluscs recovered corresponds to species of medium to large-size dimensions, whereas taxa of less than 5 mm have very seldom been mentioned before. Approximately 60% of the species recorded belong to the Orthalicidae (=Bulimulidae), the Strophocheilidae represent ca. 15%, while other families like the Xanthonychidae, Charopidae and Scolodontidae provide ca. 10% each. This review made evident that the main contributions on this subject were published by Joaquín Frenguelli who was responsible for having formed and organize the most important Quaternary terrestrial collection from Argentina, made of over a hundred lots deposited at the Museo de La Plata (Invertebrate Palaeontology Department). The synthesis on the distribution and ecological requerimients of the taxa identified provide the basic source of reference necessary to carry out future palaeoenvironmental and palaeoclimatical interpretations, complementary of research work performed based on mammals, pollen and phytoliths, as well as to select significative and reliable taxa for geochronological and isotope analyses on shells from Neogene sediments traditionally known as chronostratigraphical units (Platense, Cordobense, Bonaerense, Ensenadense of the local literature).