Contribution to the taxonomic study of Theodoxus Montfort, 1810 (Mollusca, Gastropoda: Neritidae) from the Iberian Peninsula and Balearic Islands

In this study the taxonomic status of the freshwater mollusc species of Theodoxus from the Iberian Peninsula and Balearic Islands is clarified, based on previous molecular studies carried out on more than 60 European samples. The results obtained largely corroborate the data obtained by Bunje & Lindberg (2007), and allow us to know for the moment four species in the study area: T. fluviatilis, T. meridionalis, T. mixta and T. valentinus, being these last two species mentioned very similar according to their molecular sequences. So, we maintain them as valid species. Neritina baetica and Neritina hispalensis must be considered as nomina dubia. The rest of the taxa described in the study area are considered junior synonyms of T. meridionalis. The use of the operculum to determine the species treated in the study area is questioned. In addition, at the museum level, the type series of various species such as Neritina baetica, N. hidalgoi, N. mixta, N. valentina, N. velascoi and Nerita meridionalis are reviewed, designating some of their type specimens.