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Construction of water diversions is a common response to the increasing demands for freshwater, often resulting in benefits to communities but with the risk of multiple environmental, economic, and social impacts. Water-diversion projects can favor massive introductions and accelerate biotic homogenization. This study provides empirical evidence on the consequences of a proposed law intended to divert water from two large and historically isolated river basins in Brazil: Tocantins to Sa ˜o Francisco. Compositional similarity (CS) and b-diversity were quantified encompassing aquatic organisms: mollusks, zooplankton, crustaceans, insects, fishes, amphibians, reptiles, mammals, and plants. For CS we (i) considered only native species, and (ii) simulated the introduction of non-natives and assumed the extinction of threatened species due to this water-diversion project. We highlight the environmental risks of such large-scale projects, which are expected to cause impacts on biodiversity linked to bioinvasion and homogenization, and we recommend alternatives in order to solve water-demand conflicts.

A sample of land and freshwater snails, mainly pulmonates, was recently collected in caves in Goiás and Bahia states, Brazil. Twenty-one species were found in the material. The following species are reported for the first time for Goiás state: Cecilioides consobrina (Ferussaciidae), Dysopeas muibum and Stenogyra octogyra (Subulinidae), Entodina jekylli and Prohappia besckei (Scolodontidae; also reported for the first time for Bahia state), Pupisoma dioscoricola (Valloniidae). A new species from Goiás is described herein: Gastrocopta sharae sp. n. (Gastrocoptidae). The new records and species addressed here constitute important findings, helping to fill distributional gaps and improving the knowledge of the local molluscan fauna, an essential step for future conservation efforts.

In Brazilian archaeological shellmounds, many species of land snails are found abundantly distributed throughout the occupational layers, forming a contextualized set of samples within the sites and offering a potential alternative to the use of charcoal for radiocarbon dating analyses. In order to confirm the effectiveness of this alternative, one needs to prove that the mollusk shells reflect the atmospheric carbon isotopic concentration in the same way charcoal does. In this study, 18 terrestrial mollusk shells with known collection dates from 1948 to 2004 AD, around the nuclear bombs period, were radiocarbon dated. The obtained dates fit the SH1-2 bomb curve within less than 15 years range, showing that certain species from the Thaumastus and Megalobulimus genera are reliable representatives of the atmospheric carbon isotopic ratio and can, therefore, be used to date archaeological sites in South America.

Although terrestrial gastropods are remarkably diverse, our knowledge of them is still lacking, especially for species from the Global South. As such, new tools to help researchers collect data on these organisms are very welcome. With this in mind, we investigated Brazilian observations on iNaturalist to assess the feasibility of the data available on the platform as a basis for studies on the tropical terrestrial gastropod fauna. The observations on iNaturalist were filtered by country, Brazil, and higher taxa, namely Eupulmonata, Cyclophoroidea and Helicinoidea, yielding a sample of 4,983 observations. These observations were then reviewed in search of records of rare or little-known species, species found outside their previously known range, and interesting ecological interactions. Exotic species made up 35% to 39% of the sampled iNaturalist records. The most commonly observed species were Lissachatina fulica (Bowdich, 1822), Bradybaena similaris (Férussac, 1822), Drymaeus papyraceus (Mawe, 1823), Drymaeus interpunctus (E. von Martens, 1887), Limacus flavus (Linnaeus, 1758), Meghimatium pictum (Stoliczka, 1873), Cornu aspersum (O. F. Müller, 1774), Vaginulus taunaisii (Férussac, 1821), Ovachlamys fulgens (Gude, 1900), and Bulimulus tenuissimus (Férussac, 1832). In total, 166 observations were deemed of interest to our purposes (e.g., rare species, range extensions, ecological interactions), totalling 46 identified species and 16 observations identified at genus level. Among the selected observations, we found pictures of live specimens of species that were previously known only from their shells, such as Megalobulimus pergranulatus (Pilsbry, 1901), bringing to light their appearances in life. Two potentially new species belonging to the genera Plekocheilus Guilding, 1827 and Megalobulimus K. Miller, 1878 were revealed. Additionally, we found records of living individuals of two species that were previously presumed to be possibly extinct, Leiostracus carnavalescus Simone & Salvador, 2016, and Gonyostomus egregius (Pfeiffer, 1845). We take the opportunity to discuss individual records of interest, evaluate the quality of the data and possible improvements, as well the potential and implications of the use of the iNaturalist platform for research in Brazil and other tropical countries. While iNaturalist has its limitations, it holds great potential to help document biodiversity in the tropics.

The present work deals with the vetigastropods of the family Seguenziidae collected by the Marion Dufresne (MD55) expedition in SE Brazil, reporting the occurrence of eight species. The following species have their geographical range extended: Ancistrobasis costulata, Carenzia carinata, Carenzia trispinosa, Hadroconus altus, Seguenzia elegans and Seguenzia formosa. Two new species, Halystina umberlee sp. nov. and Seguenzia triteia sp. nov., are described.

ABSTRACT.A remarkable new species of pulmonate land snail was found in the collection of the Senckenberg Forschungninstitut und Naturmuseum Frankfurt (Frankfurt am Main, Germany) and is described here as Leiostracus faerie sp. nov. It can be easily identified by its small and translucent shell with fine axial light brown bands and its protoconch sculpture. It was collected in the Rio Doce ("Doce River") region in Espírito Santo, Brazil, an area known for a high diversity and endemicity of land snails. This discovery shows how little this fauna is known and reinforces the importance of museum collections in the study of biodiversity and conservation.KEYWORDS. Atlantic Forest; Leiostracus faerie sp. nov.; Rio Doce, Stylommatophora.RESUMO. Nova espécie de Leiostracus (Gastropoda, Pulmonata, Orthalicoidea) do Espírito Santo, Brasil. Uma extraordinária espécie nova de gastrópode pulmonado foi encontrada na coleção do Senckenberg Forschungninstitut und Naturmuseum Frankfurt (Frankfurt am Main, Alemanha) e é aqui descrita como Leiostracus faerie sp. nov. Esta espécie pode ser facilmente identificada por sua concha diminuta e translúcida, com finas faixas axiais marrom-claras, e pela escultura de sua protoconcha. Ela é originária da região do Rio Doce, Espírito Santo, uma área conhecida por sua grande diversidade e endemicidade de gastrópodes terrestres. Esta descoberta mostra quão pouco é conhecida essa fauna e também reforça a importância das coleções de museus no estudo da biodiversidade e em medidas de conservação. PALAVRAS-CHAVE.Leiostracus faerie sp. nov.; Mata Atlântica; Rio Doce; Stylommatophora.

New records for Helicina schereri Baker, 1913, are reported. It was a species previously restricted to the states of Ceará, Rio Grande do Norte, Paraíba, Alagoas and Tocantins in Northeastern Brazil, and State of Santa Catarina, much further south. The new occurrences reported herein fill distribution gaps and also significantly expand the range of the species ca. 970 km westwards. The new records are from the following locations: Bahia State (Ituaçu and Itaquara municipalities) in Northeast Brazil; Mato Grosso do Sul State (Bonito Municipality) in the Midwest; and Minas Gerais (Lagoa Santa municipality) in the Southeast.