Elisavet Georgopoulou

Tectonics, climate, and the rise and demise of continental aquatic species richness hotspots.

Significance To our knowledge, this study is the first investigation of the evolution of species richness hotspots in continental aquatic systems. We demonstrate the development of European richness hotspots over the last 23 My based on a comprehensive dataset combining recent and fossil occurrences of gastropod species. We show that changes in species richness patterns can be related to geodynamic and climatic processes. The addition of tectonics, geological time, and spatial scales to ecology and climate is essential for understanding hotspot development in general. These insights also provide a foundation to explain the modern, uneven distribution of species richness as a whole. The pattern for Recent European faunas is a geologically young phenomenon, triggered by the ice sheet retreat after the Last Glacial Maximum. 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.

Synopsis of European Neogene freshwater gastropod localities: updated stratigraphy and geography

The last overview of Cenozoic localities with records of freshwater gastropods was provided more than 80 years ago. Since then, a wealth of new information has been published: new localities have been discovered and fundamental changes occurred in regional stratigraphy. In addition, many localities are still attributed to erroneous or outdated stratigraphical concepts even in recent papers. Geopolitical evolution of Europe has, furthermore, led to name changes and confusion regarding the exact origin of samples in collections. Here we provide a fully georeferenced dataset for almost all published Miocene and Pliocene freshwater gastropod localities (2,930), including updated stratigraphic data where possible. This basic update will serve as an essential fundament for any future work related to the freshwater deposits and respective faunas in general. Thomas A. Neubauer. Geological-Paleontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria thomas.neubauer@nhm-wien.ac.at Elisavet Georgopoulou. Geological-Paleontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria elisavet.georgopoulou@nhm-wien.ac.at Andreas Kroh. Geological-Paleontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria andreas.kroh@nhm-wien.ac.at Mathias Harzhauser. Geological-Paleontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria mathias.harzhauser@nhm-wien.ac.at Oleg Mandic. Geological-Paleontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria oleg.mandic@nhm-wien.ac.at Daniela Esu. Dipartimento di Scienze della Terra, “Sapienza” University of Rome, P.le A. Moro 5, 00185 Rome, Italy daniela.esu@uniroma1.it

Synopsis of valid species-group taxa for freshwater Gastropoda recorded from the European Neogene.

Abstract Here we present a complete list of all valid species-group taxa of freshwater gastropods reported from Miocene and Pliocene deposits in Europe. The last comparable work dates back to the 1920s and covered about 1,600 names. The extensive literature research underlying the present work revealed considerable changes in the taxonomic and systematic frameworks of Neogene freshwater gastropods and yielded a total number of 2,156 accepted taxa. Each taxon is accompanied by a full citation of its first description; where the information is available, page number and illustration reference are provided. First descriptions available as open-access full-text sources on the web were linked via hyperlink to the first page of the publication.

Distribution patterns of European lacustrine gastropods: a result of environmental factors and deglaciation history

Contemporary climate and deglaciation history have received strong support as drivers of species richness and composition for several European taxa. We explored the influence of these factors on patterns of species richness and faunal composition of 244 freshwater gastropod species from 898 European lakes. We evaluated the influence of late Pleistocene deglaciation and seven physiographical and climatic factors on gastropod distributions using multiple linear regression models. We investigated species beta diversity patterns and the influence of species dispersal abilities and/or environment on species composition between lake subsets with different deglaciation history. Contemporary factors and deglaciation history explain parts of variation in species richness across European lakes. Beta diversity analysis revealed moderate to high differences in species composition between the predefined groups. Patterns of species replacement and species loss indicate that lacustrine gastropod faunas of formerly glaciated areas are subsets of non-glaciated ones. Dispersal limitations and environmental gradients control patterns of beta diversity within different lake subsets. We find strong support that the distribution of European limnic gastropods, at least partially, carries the imprint of the last Ice Age. The differences in species richness and composition point towards a gradual, ongoing process of species recolonization after deglaciation.

An outline of the European Quaternary localities with freshwater gastropods: Data on geography and updated stratigraphy

Fossil and subfossil freshwater gastropods of the European Quaternary have been studied extensively by numerous authors during the nineteenth and twentieth centuries. Despite the wealth of information, these papers usually focus on regional aspects. Geographic names, however, may have changed due to politics and the stratigraphy is outdated in many cases. Since then, numerous papers improved the taxonomic understanding of certain groups of freshwater gastropods and revised the often confused nomenclatural history. Nevertheless, no efforts were made to collect and summarize the data on a pan-European scale in order to compare them. This study focuses specifically on recording Pleistocene and Holocene localities of Europe and some adjacent Asian countries bearing freshwater gastropods, combined with updated stratigraphic information when available. This resulted in a dataset of 1473 localities, which may serve as a base for future analyses of Eurasian post-Pliocene freshwater systems and their biota. Elisavet Georgopoulou. Geological-Palaeontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria; Institute for Earth Sciences, University of Graz, Heinrichstraße 26, 8010 Graz, Austria. elisavet.georgopoulou@nhm-wien.ac.at Thomas A. Neubauer. Geological-Palaeontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria. thomas.neubauer@nhm-wien.ac.at Andreas Kroh. Geological-Palaeontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria. andreas.kroh@nhm-wien.ac.at Mathias Harzhauser. Geological-Palaeontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria. mathias.harzhauser@nhm-wien.ac.at Oleg Mandic. Geological-Palaeontological Department, Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria. oleg.mandic@nhm-wien.ac.at

Replacement names and nomenclatural comments for problematic species-group names in Europe's Neogene freshwater Gastropoda

Over the last 250 years of taxonomic descriptions of freshwater gastropods a large number of primary and secondary homonyms were produced. Several of them have now been uncovered in the course of a new database project. To overcome the associated nomenclatural problems we propose 10 replacement names: Theodoxus pseudodacicus nom. nov., Theodoxus stoicai nom. nov., Viviparus deleeuwi nom. nov., Viviparus lubenescuae nom. nov., Viviparus wesselinghi nom. nov., Melanopsis anistratenkoi nom. nov., Melanopsis gearyae nom. nov., Melanopsis magyari nom. nov., Melanopsis vrcinensis nom. nov., and Pyrgula rusti nom. nov. Additionally, we discuss taxa that might become secondary homonyms because of uncertain genus attributions. The genera Melanoptychia Neumayr, 1880 and Boistelia Cossmann, 1909 are synonymized with Melanopsis Férussac, 1807 in Férussac & Férussac, 1807 based on the lack of sufficient separation criteria. Involved combinations are expounded and recombined accordingly. The nomenclatural problems regarding Melanopsis costata Fuchs, 1870 (non Olivier, 1804) and Planorbis varians Fuchs, 1870 sensu Bandel (2010) are discussed.

Predictors of shell size in long-lived lake gastropods.

Abstract Aim To investigate shell size variation among gastropod faunas of fossil and recent long‐lived European lakes and discuss potential underlying processes. Location Twenty‐three long‐lived lakes of the Miocene to Recent of Europe. Methods Based on a dataset of 1412 species of both fossil and extant lacustrine gastropods, we assessed differences in shell size in terms of characteristics of the faunas (species richness, degree of endemism, differences in family composition) and the lakes (surface area, latitude and longitude of lake centroid, distance to closest neighbouring lake) using multiple and linear regression models. Because of a strong species–area relationship, we used resampling to determine whether any observed correlation is driven by that relationship. Results The regression models indicated size range expansion rather than unidirectional increase or decrease as the dominant pattern of size evolution. The multiple regression models for size range and maximum and minimum size were statistically significant, while the model with mean size was not. Individual contributions and linear regressions indicated species richness and lake surface area as best predictors for size changes. Resampling analysis revealed no significant effects of species richness on the observed patterns. The correlations are comparable across families of different size classes, suggesting a general pattern. Main conclusions Among the chosen variables, species richness and lake surface area are the most robust predictors of shell size in long‐lived lake gastropods. Although the most outstanding and attractive examples for size evolution in lacustrine gastropods come from lakes with extensive durations, shell size appears to be independent of the duration of the lake as well as longevity of a species. The analogue of long‐lived lakes as ‘evolutionary islands’ does not hold for developments of shell size because different sets of parameters predict size changes.