The Dinaride Lake System, as one of the largest freshwater systems in the Neogene of Europe, is widely known for its exceptional mollusc fauna. During the Early and Middle Miocene, it displayed a major evolutionary hotspot resulting in a high level of endemicity. Despite advanced investigations in that region, comprehensive knowledge on the mollusc fauna of the Kupres basin is largely lacking. The herein presented results give insight into this outstandingly preserved fauna and are the base for a systematic revision of several supraspecific taxa among the Hydrobiidae. Because their phylogeny is poorly known, this study may serve as starting point for an overall systematic revision of this highly diverse family. Moreover, the faunal composition allows inferences on palaeobiogeography and hydrological connections within the Dinaride Lake System during the early Middle Miocene. About one-third of the described taxa are restricted to the Kupres basin. The other taxa document faunistic relations to the coeval faunas of the Sinj, Drniš and Džepi basins. Phases of hydrological isolation, indicated by carbonate dominated lithology, coincide with a high frequency of sculptured morphologies within the gastropods. Phases of increased aridity led to high evaporation, a lowered lake level and enhanced carbonate production which seem to have promoted strongly calcified shells. The stratigraphic ranges of the species imply a depositional age of 15.5 ± 0.2 Ma (earliest Middle Miocene; Langhian). Among the Hydrobiidae Cyclothyrella gen. nov. and Pseudodianella gen. nov. are introduced as new genera. Bania obliquaecostata sp. nov., Melanopsis corici sp. nov., Nematurella vrabaci sp. nov., Prososthenia diaphoros sp. nov. and Prososthenia undocostata sp. nov. are described as new species. For the secondary homonym Melanopsis bittneri (Neumayr, 1880), the new name Melanopsis medinae nom. nov. is proposed.

Aim Elevated biodiversity is the result of the cradle, museum or sink functions. The contributions of these three functions to species accumulation and their changes through time remain unknown for glacial refugia. Additionally, our understanding of the role these functions played during pre‐glacial periods is limited. We test for changes in contributions of functions through time leading to the current diversity patterns using a model refugium and taxon. Location Anatolia, Western Palaearctic. Taxon Freshwater neritid snails (genus Theodoxus). Methods Assessments were made to define molecular operational taxonomic units (MOTUs) for Theodoxus and reaffirm the genus as a suitable model taxon with elevated interspecific diversity in noted glacial refugia. Thereafter, we constructed a time‐calibrated multilocus Bayesian phylogeny of mtDNA and nDNA by using both fossil data and published substitution rates. Ancestral area estimation was performed on the phylogeny to define the contribution of the functions through time. Results Accumulation of Theodoxus diversity in Anatolia over the Miocene–Pliocene transition is attributed to the museum function, but its contribution was small as only few divergence events occurred. The cradle function dominated during the Pliocene and Early Pleistocene, when most interspecific diversity built up and extant lineages in Anatolia were established. The sink function acted from the Middle Pleistocene to present‐day, but with only a small contribution to the total extant Anatolian interspecific diversity. Main conclusion Our results do not entirely mitigate the role glacial cycles played in species accumulation, but highlight Ice Ages may have been less effective in forcing temperate aquatic interspecific diversity into more opportune areas. The elevated diversity in refugia may rather be the result of earlier in situ diversification. Elevated interspecific diversity attributed to the legacy of glacially forced retreats may need to be re‐evaluated in cases where refugia have long and complex geological histories such as Anatolia. These results highlight the importance of considering species accumulation through a temporal perspective to adequately explain present‐day biodiversity patterns.

For the first time a palaeobiogeographic framework is proposed for European Neogene freshwater systems. The distribution of 2226 species-group taxa of freshwater gastropods from over 2700 Miocene and Pliocene localities was evaluated. The localities were grouped into palaeo-freshwater systems based on latest palaeogeographic reconstructions. Cluster analyses were computed for four time slices, i.e., Early Miocene, Middle Miocene, Late Miocene, and Pliocene. The analyses demonstrate a generally high degree of provincialism for the Neogene freshwater systems and allow the definition of biogeographic units. The delimitations are based on the cluster analyses, the degree of endemicity, and geographical coherence. The Early Miocene is characterised by a relatively low degree of provincialism suggesting the distinction of three regions. Coinciding with the development of many endemic systems on the Dinarian-Anatolian Island and in central Europe, the Middle Miocene demonstrates a higher degree of provincialism, allowing the definition of six biogeographic regions. With the onset of the Late Miocene the retreat of the Central Paratethys and development of the huge Lake Pannon massively shaped faunal evolution and palaeobiogeography in general. The formation of the 'Lago-mare' environment fringing the Mediterranean Basin as well as the development of several restricted freshwater systems in western Europe additionally promoted biogeographic division. The increasing provincialism allowed the delimitation of six biogeographic regions, three of which could be subdivided into seven dominions. With the disappearance of Lake Pannon and the decline of western European and Mediterranean faunas at the Miocene-Pliocene boundary, biodiversity hotspots shifted towards eastern and southeastern Europe. For the Pliocene, four biogeographic regions, five dominions, and four provinces were defined. Most of the here proposed biogeographic units and faunal differences are governed by the varied existence of large, long-lived systems. Because of their prolonged duration they immensely influenced the community composition on the family level, differences of the relative species richnesses per biogeographic region, and the rising rate of endemicity. The underlying mechanism for this pattern is the ongoing continentalization of Europe triggered by the Alpidic orogenesis and the simultaneous retreat of the Paratethys Sea. The continuing restriction of this huge intracontinental sea from the Mediterranean promoted the evolution of endemic freshwater faunas. The arising long-lived systems like Lake Pannon, Lake Dacia or Lake Slavonia persisted over several millions of years and stimulated the evolution of highly diverse and endemic faunas.

Defining and recording the loss of species diversity is a daunting task, especially if identities of species under threat are not fully resolved. An example is the Pontocaspian biota. The mostly endemic invertebrate faunas that evolved in the Black Sea – Caspian Sea – Aral Sea region and live under variable salinity conditions are undergoing strong change, yet within several groups species boundaries are not well established. Collection efforts in the past decade have failed to produce living material of various species groups whose taxonomic status is unclear. This lack of data precludes an integrated taxonomic assessment to clarify species identities and estimate species richness of Pontocaspian biota combining morphological, ecological, genetic, and distribution data. In this paper, we present an expert-working list of Pontocaspian and invasive mollusc species associated to Pontocaspian habitats. This list is based on published and unpublished data on morphology, ecology, anatomy, and molecular biology. It allows us to (1) document Pontocaspian mollusc species, (2) make species richness estimates, and (3) identify and discuss taxonomic uncertainties. The endemic Pontocaspian mollusc species richness is estimated between 55 and 99 species, but there are several groups that may harbour cryptic species. Even though the conservation status of most of the species is not assessed or data deficient, our observations point to deterioration for many of the Pontocaspian species.

This study provides the first assemblage-based taxonomic revision of the mollusk fauna of the Middle Miocene Dinaride Lake System (DLS). The assemblage, consisting of more than 13.000 specimens, was sampled from a 100-m-thick Lower Langhian interval of the Lučane section in the Sinj Basin (Croatia). 18 gastropod species and 3 bivalve species are detected from the succession. All are endemic to the Dinaride Lake System. Within that system, the described fauna of Lake Sinj displays strong similarities with the coeval and geographically close fauna of Lake Drniš. Reduced faunistic relations to other lakes of the DLS are discussed to result from slightly different stratigraphic ages and deviating paleoecologic settings. Many melanopsid and prososthenid gastropod taxa in the literature are considered to be mere morphotypes of few polymorphic species resulting in nomenclatorial rectifications. Melanopsis lucanensis Neubauer n. sp. and Belgrandia klietmanni Neubauer n. sp. are introduced as new species.

The present contribution displays a taxonomic and systematic revision of the exceptionally rich mollusk fauna of the Middle Miocene Lake Drniš, Southern Croatia. In total, 44 species of freshwater mollusks (36 freshwater gastropods, 8 bivalves) and 5 species of terrestrial gastropods are recorded. The assemblage is dominated by melanopsids and hydrobiids concerning number of species and individuals. Such a composition is typical among the coeval paleolakes of the Dinarides and is indicative of a perennial, moderately shallow setting. The fauna proves the highly endemic character of the Dinaride Lake System: 95.4 % of the freshwater species recorded for Lake Drniš only occur within this system. Moreover, the fauna shows a particularly strong relation-ship with that of nearby Lake Sinj (79.5 %). Only four freshwater species (9.1 %) are endemic to Lake Drniš. The present work ties the fauna to the stratigraphical framework established for the coeval Dinaride lakes Sinj, Kupres, and Gacko, and suggests an age of ca. 15.7-15.0 Ma, classifying the deposits into the early Middle Miocene (early Langhian).Among

Continental aquatic species richness hotspots are unevenly distributed across the planet. In present-day Europe, only two centers of biodiversity exist (Lake Ohrid on the Balkans and the Caspian Sea). During the Neogene, a wide variety of hotspots developed in a series of long-lived lakes. The mechanisms underlying the presence of richness hotspots in different geological periods have not been properly examined thus far. Based on Miocene to Recent gastropod distributions, we show that the existence and evolution of such hotspots in inland-water systems are tightly linked to the geodynamic history of the European continent. Both past and present hotspots are related to the formation and persistence of long-lived lake systems in geological basins or to isolation of existing inland basins and embayments from the marine realm. The faunal evolution within hotspots highly depends on warm climates and surface area. During the Quaternary icehouse climate and extensive glaciations, limnic biodiversity sustained a severe decline across the continent and most former hotspots disappeared. The Recent gastropod distribution is mainly a geologically young pattern formed after the Last Glacial Maximum (19 ky) and subsequent formation of postglacial lakes. The major hotspots today are related to long-lived lakes in preglacially formed, permanently subsiding geological basins.biogeography | hotspot evolution | freshwater gastropods | Cenozoic | species-area relationship

The Caspian Sea has been a highly dynamic environment throughout the Quaternary and witnessed major oscillations in lake level, which were associated with changes in salinity and habitat availability. Such environmental pressures are considered to drive strong phylogeographic structures in species by forcing populations into suitable refugia. However, little is actually known on the effect of lake-level fluctuations in the Caspian Sea on its aquatic biota. We compared the phylogeographic patterns of the aquatic Neritidae snail genus Theodoxus across the Pontocaspian region with refugial populations in southern Iran. Three gene fragments were used to determine relationships and divergence times between the sampled populations in both groups. A dated phylogeny and statistical haplotype networks were generated in conjunction with the analyses of molecular variance and calculations of isolation by distance using distance-based redundancy analyses. Extended Bayesian skyline plots were constructed to assess demographic history. Compared with the southern Iranian populations, we found little phylogeographic structure for the Pontocaspian Theodoxus group, with more recent diversification, homogeneity of haplotypes across the Pontocaspian region and a relatively stable demographic history since the Middle Pleistocene. Our results argue against a strong influence of Caspian Sea low stands on the population structure post the early Pleistocene, whereas high stands may have increased the dispersal possibilities and homogenization of haplotypes across the Pontocaspian region during this time. However, during the early Pleistocene, a more dramatic low stand in the Caspian Sea, around a million years ago, may have caused the reduction in Theodoxus diversity to a single lineage in the region. In addition, our results provide new insights into Theodoxus taxonomy and outlooks for regional conservation.