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The gastropod genus Litthabitella Boeters, 1970, type species L. chilodia Westerlund, 1886, inhabits mainly freshwater springs in the coastal regions of the Balkan Peninsula from Greece to Slovenia, southern Italy and the Ionian Islands. These snails are minute and show several synapomorphic character states, such as: broadly ovate osphradium, gonopore deep inside the mantle cavity, thickened circular oviduct, distal termination of the penis wide with a sharp and short lateral filament and two flat, cockscomb-like, four-folded lobes. These characters justify a family rank for the taxon. Three molecular loci – mitochondrial cytochrome oxidase subunit I, nuclear 18S and histone H3 – also confirm the distinctiveness of the Litthabitellidae fam. nov. Analysis of molecular data indicates an estimated time of origin in the Late Miocene (Tortonian) and supports its position as the sister clade of the Hydrobiidae. The shells, protoconchs, radulae, operculum, some histology, female reproductive organs and penis are herein illustrated and described. Molecular data presented for 10 studied populations, confirmed partly by morphological characters, indicate four distinct taxa of species rank. Three species are described: Litthabitella aquaadcrucem sp. nov., Litthabitella cetinensis sp. nov. and Litthabitella levkadensis sp. nov. [ABSTRACT FROM AUTHOR]

Shell features are key factors for systematics and evolutionary biology studies of freshwater gastropods. Based mostly on shell morphology, 19 species of the springsnail genus Radomaniola (family Hydrobiidae) have been described. Although the scarce differentiation of various shell dimensions suggests morphological stasis, the evolutionary dynamics of shell and other anatomical structures have not yet been explored fully. By inferring a phylogeny and a time-calibrated species tree from mitochondrial (COI and 16S) and nuclear (28S) sequences of 15 recognized species, we initially examine the species diversity of the Radomaniola dataset and then, through phylogenetic comparative methods, assess the evolutionary correlation, pace and mode of 40 continuous shell and anatomical characters. By synthesizing the results of four species delimitation methods and through morphological examinations, we recognize 21 groups, for which taxonomy is discussed here. Seven new species are described. We reveal a high degree of correlated evolution between characters of the shell, which are constrained by a single morphological optimum, consistent with the morphological stasis model. Anatomical traits diverged rapidly in an unconstrained manner or toward multiple optima. These findings indicate that in order to understand the morphological evolution of springsnails, it is essential to examine different organs in detail. [ABSTRACT FROM AUTHOR]

The Balkan Peninsula is inhabited by the worldwide most diverse subterranean gastropod fauna. This fauna is still poorly studied, since its habitats are not easily accessible, and its sampled populations are mostly not rich in specimens' numbers. Often only empty shells are known, but the shell is hardly useful, not only in phylogeny reconstruction, but even in species determination. The exclusively obligatory subterranean family Moitessieriidae is especially poorly studied. Representatives of the genus Paladilhiopsis Pavlović, 1913 (Moitessieriidae) collected at three localities, distributed in Croatia and Bosnia & Herzegovina, were studied. The pigmentation of their shells and soft parts, as well as the female and male reproductive organs in one taxon, are presented. The partial sequences of the molecular markers mitochondrial cytochrome oxidase subunit I (COI) and nuclear histone 3 (H3) were used to infer their systematic status and phylogenetic relationships. Two species new to science are described. For one of them, also studied anatomically, 15 specimens were sequenced for COI, and all show the same haplotype. [ABSTRACT FROM AUTHOR]

A new species of Kerkia, K. briani Rysiewska & Osikowski, sp. nov. is described from the spring Polički Studenac Vrelo (Crkvina), adjacent to the Trebišnjica River (Bosnia and Herzegovina) collected with Bou-Rouch technique, pumped from an interstitial habitat 50 cm below the bottom of the spring. The shell, female reproductive organs, and the penis are described and illustrated. Mitochondrial cytochrome oxidase subunit I (COI) and nuclear histone H3 partial sequences confirm the distinctness of the new species, and molecularly based phylogenetic relationships of Kerkia are briefly presented. [ABSTRACT FROM AUTHOR]