New data on Hydrobiidae systematics: two new genera from the Iberian Peninsula

A deep systematic study of the Spanish hydrobiid fauna is unravelling a mor e complex group of species than was previously described. The use of differ ent taxonomical and statistical methodologies helps to clarify this old cla ssification. Based on anatomical studies made for the first time on specime ns from the type locality of Paludina sturmi (Rosenhauer, 1856), the specie s is redescribed and transferred to a new genus Boetersiella. The study dem onstrates that Horatia (?) sturmi (sensu Boeters, 1988) is a combination of two species belonging to two new, different but closely related genera, B. sturmi and Chondrobasis levantina gen. and sp. nov. A second species for t he first genus, B, davisi, is also described. Morphometrical analysis (MANO VA and DFA) combining species of both genera showed clear differences in so me shell variables although the most valuable discriminant characters are r elated to the female and male genital systems and to the size and shape of the osphradium. Boetersiella mainly differs from Chondrobasis in having a s imple penis while a small basal penial lobe is present in the second; in ad dition, the distal seminal receptacle is bigger in Boetersiella and leans o ver the bursa copulatrix instead of over the renal oviduct as is the case i n Chondrobasis. The two new genera differ from Horatia Bourguignat, 1887 in three main characters: the lack of a ctenidium, the presence in the female genitalia of only one seminal receptacle in a distal position and a penis simple (in Boeteisiella) or with a small lobe close to its basis (in Chondr obasis). None of these characters are present in the type species Horatia k lecakiana (Bourguignat, 1887). Both sets of character/character-states also differ from the other two valvatiform genera described for the Iberian Pen insula, Neohoratia Schutt, 1961 and Tarraconia Ramos and Arconada (in Ramos et al., in press). Comparisons with other European valvatiform genera were made although the lack of accurate anatomical data for most of them preven ted any cladistical approach.