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

Abstract

A deep systematic study of the Spanish hydrobiid fauna is unravelling a more complex group of species than was previously described. The use of diOE erent taxonomical and statistical methodologies helps to clarify this old classi® cation. Based on anatomical studies made for the ® rst time on specimens from the type locality of Paludina sturmi (Rosenhauer, 1856), the species is redescribed and transferred to a new genus Boetersiella. The study demonstrates that Horatia (?) sturmi (sensu Boeters, 1988 ) is a combination of two species belonging to two new, diOE erent but closely related genera, B. sturmi and Chondrobasi s levantina gen. and sp. nov. A second species for the ® rst genus, B. davisi, is also described. Morphometrical analysis (MANOVA and DFA) combining species of both genera showed clear diOE erences in some shell variables although the most valuable discriminant characters are related to the female and male genital systems and to the size and shape of the osphradium. Boetersiella mainly diOE ers from Chondrobasis in having a simple penis while a small basal penial lobe is present in the second; in addition, the distal seminal receptacle is bigger in Boetersiella and leans over the bursa copulatrix instead of over the renal oviduct as is the case in Chondrobasis. The two new genera diOE er 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 Boetersiella) or with a small lobe close to its basis (in Chondrobasis). None of these characters are present in the type species Horatia klecakiana (Bourguignat, 1887). Both sets of character / character-states also diOE er from the other two valvatiform genera described for the Iberian Peninsula, Neohoratia Schu È tt, 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 prevented any cladistical approach.

The ibero-balearic region: one of the areas of highest Hydrobiidae (Gastropoda, Prosobranchia, Rissooidea) diversity in Europe

“…In 1988, Boeters published a revision of the Hydrobiidae and Moitessieridae families on the Iberian Peninsula, dividing them into four subfamilies: Horatiinae, Hydrobiinae, Amnicolinae and Potamopyrginae. Other papers (Boeters & Rolán, 1988;Rolán, 1991;Ramos et al, 2000;Arconada & Ramos, 2001 published in the last decades about hydrobiids on the Iberian Peninsula described many new genera and species (e.g., Chondrobasis, Boetersiella, Spathogyna and Tarraconia). The most important changes have been noted among valvatiform hydrobiids (Arconada, 2000): where Boeters (1988) only recognised two genera (Horatia and Neohoratia) and nine species, there are currently nine genera and 19 species, some of which are still unpublished.…”

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“…The paper described the presence of a new hydrobiid species in a locality from Southern Spain that was assigned to the genus Boetersiella Arconada & Ramos, 2001. The species was named Boetersiella wolfi in honor of Wolfgang Graack who collected it in 2001.…”

“…We have no doubt about the incorrect adscription of the new species to Boetersiella and therefore we consider that the original diagnosis of this genus is still valid as defined by its authors (see Arconada & Ramos, 2001).…”

“…Hydrobiids taxonomy has been traditionally based on penis structure and the number and position of the sac-like structures associated with the renal oviduct (bursa copulatrix and seminal receptacles) (Bodon et al, 2001). It is well known that the genital characters and combinations between them are generally constant in groups of species of western Palaeartic hydrobiids and are therefore the most relevant diagnostic features at the rank of genus (Davis & Carney, 1973;Bodon et al, 2001;Arconada & Ramos, 2001, 2006Ramos et al, 2000).…”

“…The species was named Boetersiella wolfi in honor of Wolfgang Graack who collected it in 2001. In order to justify the inclusion of the new species into this genus Boeters & Gloer (2007) modified the diagnostic characters defined for Boetersiella (Arconada & Ramos, 2001) by broadening them. It is necessary to point out that in addition to these modifications, the new species also differs in other fundamental diagnostic characters that are not explained or justified by Boeters and Gloer (2007).…”