Synopsis of the terrestrial and freshwater gastropod fauna of southern Bahia, Brazil

The terrestrial and freshwater malacofauna of southern Bahia is little known, especially in comparison to the well-studied eastern portion of the state covered by remnants of Atlantic Forest. We present here a synopsis of all gastropod species known from the central southern region of Bahia state, known as ‘Centro-Sul Baiano’, focusing on four municipalities: Condeúba, Cordeiros, Mortugaba, and Piripá. The list herein contains data from the literature, historical material deposited in museum collections, and two recent expeditions undertaken in the region. The survey resulted in 21 species of gastropods, with nearly 700 voucher specimens (mostly freshwater) deposited in the collection of the Museu de Zoologia da Universidade de São Paulo (São Paulo, Brazil). Circa 30% of the species are non-indigenous; previously, the only known exotic in the region was Melanoides tuberculata (Müller, 1774). The family Achatinidae was the most diverse group in number of native species, while the typically diverse superfamily Orthalicoidea was represented by only two species.

Studi Morfologi, Ontogeni, Dan Strategi Reproduksi Pada Melanoides Tuberculata (Müller , 1774) Dan Stenomelania Punctata (Lamarck, 1822) (Gastropoda: Cerithioidea: Thiaridae)

The freshwater Melanoides tuberculata (Thiarid) has wide distribution and have many variation in color, size, and scluptured of their shells. Comparing with another Thiarid so called Stenomelania punctata, shell of M. tuberculata similar in having turreted shape, blackish color, number of whorls, and size of the shells. This study aim to compare more detailed between M. tuberculata and S. punctata based on their morphology, ontogeny and type of reproduction. Ontogeny studies of these two species show that M. tuberculata produces juveniles in embryonic shell form during their reproduction. This embryonic shell is nourished and developed in the subhaemocoelic brood-pouch organ as evidenced by being found in the size range 0.12–5.95 mm. One individu M. tuberculata can produce 1–66 embryonic shells. Meanwhile, in subhaemocoelic brood-pouch of S. punctata only the unshell embryo was seen and embryonic shell was not found. The difference of reproduction system determines the reproductive strategy in both species. M. tuberculata conduct euviviparity reproduction whereas S. punctata is ovoviviparous that releases juveniles in free-swimming veliger form.

FRESHWATER SNAIL DIVERSITY IN GROWOUT PONDS OF GIANT GOURAMI REGARDING INTERMEDIATE HOSTS OF TREMATODE LARVAE (CERCARIAE STAGE) IN TIEN GIANG PROVINCE

Nghiên cứu thành phần loài ốc nước ngọt và tỉ lệ nhiễm sán lá song chủ (giai đoạn cercariae) trên ốc trong ao nuôi cá thịt tai tượng ở huyện Châu Thành, tỉnh Tiền Giang được thực hiện vào tháng 10/2020 và tháng 4/2021. Tổng số 4548 mẫu từ 8 loài ốc, 8 giống, 4 họ đã được thu và phân loại dựa theo đặc điểm hình thái. Kết quả cho thấy, ốc Melanoides tuberculata bị nhiễm Xiphidio cercariae và Furcocercous cercariae trong khi ốc Bithynia sp. nhiễm Xiphidio cercariae và Parapleurolophocercous cercariae. Sáu loài ốc còn lại không nhiễm cercariae bao gồm Filopaludina sumatrensis, Pomacea sp., Sermyla tornatella, Sinotaia lithophaga, Tarebia granifera và Thiara scabra. Tỉ lệ ao nhiễm cercariae trong mùa khô cao hơn trong mùa mưa (P>0.05). Cần tiếp tục nghiên cứu dịch tễ học của sán lá song chủ trong ao nuôi cá tai tượng nhằm góp phần phát triển nuôi trồng thủy sản bền vững và an toàn vệ sinh thực phẩm.

The freshwater molluscs of Serbia: Annotated checklist with remarks on distribution and protection status

We present a checklist of 86 valid freshwater mollusc species of Serbia (65 gastropods and 21 bivalves) belonging to 19 families (15 gastropods and four bivalves). The list is based on our latest research and includes data from published sources and personal communications. The most diverse family among gastropods is Planorbidae (16 species), while Sphaeriidae are most diverse within the bivalves (10 species). Ten species are local endemics (all of them gastropods), while eight are introduced species (three gastropods and five bivalves). The Danube River and its smaller tributaries harbour the most diverse gastropod community, with a total of 61 species (41 gastropods and 20 bivalves). The snail Theodoxus transversalis (Pfeiffer, 1828) and the bivalve Unio crassus Philipson, 1788 are listed as EN (endangered) on the global (IUCN) level, while the snail Plagigeyeria gladilini Kuščer, 1937 and the bivalves Pseudanodonta complanata (Rossmässler, 1835) and Sphaerium rivicola (Lamarck, 1818) are considered as VU (vulnerable) species. Of those IUCN taxa, only U. crassus is listed as protected on the national level (along with 12 mostly local endemic gastropod species). In comparison with the previous checklist of gastropods by Karaman & Karaman (2007), a total of seven species are added here: Belgrandiella serbica Glöer 2008, Bythinella istoka Glöer & Pešić 2014, B. nonveilleri Glöer 2008, B. pesterica Glöer 2008, Acroloxus lacustris (Linnaeus, 1758), Melanoides tuberculata (O.F. Müller, 1774) and Armiger crista (Linnaeus, 1758). In view of global and regional trends in taxonomy, ecology and invasive biology, an even richer diversity of the Serbian freshwater malocofauna can be expected.

Freshwater mollusks as proxies for assessing agrochemicals hazards in Volta Grande Reservoir, Brazil

Brazil has experienced a rise in the use of agrochemicals in recent years, representing a potential threat to nearby ecosystems. The Volta Grande Reservoir (Minas Gerais/São Paulo, Brazil) has about 87% of its area surrounded by agricultural systems, and many compounds used in agriculture end up being carried into nearby water bodies. Given the potential ecological risk, our purpose was to assess pesticides in the reservoir. We collected specimens of two bivalves and three gastropods using bottom dredging and visual investigation in three different sites within the reservoir. The sampling sites were classified according to their distance from the dam, and all were close to agricultural lands. The samples were processed and frozen for qualitative toxicological analysis using mass spectrophotometry. Eight pesticides were identified, including four organochlorines (Aldrin, p,p’-DDE, Heptachlor epoxide, and Endrin) and organophosphates (Disulfoton, Malathion, Parathion- methyl, and Parathion-ethyl). All five studied species (Limnoperna fortunei, Corbicula fluminea, Melanoides tuberculata, Aylacostoma tenuilabris, and Pomacea aff. canaliculata) presented traces of pesticides in their bodies. Of the eight pesticides found in our analysis, six are illegal in Brazil, raising awareness about the continuous use of forbidden pesticides, and also the ecological risk in the Volta Grande Reservoir area. Our results suggest stricter control by environmental agencies regarding the use and commercialization of these illegal toxic compounds.

TOXICIDAD DE LOS BIOPLAGUICIDAS AGAVE AMERICANA, FURCRAEA ANDINA (ASPARAGACEAE) Y SAPINDUS SAPONARIA (SAPINDACEAE) SOBRE EL CARACOL INVASOR MELANOIDES TUBERCULATA (THIARIDAE)

Una de las familias de plantas más estudiadas para la búsqueda de nuevos agentes terapéuticos es la Asparagaceae, la cual comprende 2480 especies, Agave americana L., conocida como cabuya azul y Furcraea andina Trel. conocida como cabuya pertenecen a esta familia. Sapindus saponaria L. (Sapindaceae) conocida como boliche o choloque, es una planta arbórea de amplia distribución, en cuyos frutos se ha observado efectos larvicidas sobre garrapatas, actividad antimicrobiana, espermicida, fungicida y molusquicida. Melanoides tuberculata (Muller 1774) (Gastropoda: Thiaridae) es un caracol actualmente de distribución cosmopolita, con énfasis en el ámbito tropical y que presenta una alta importancia ecológica como invasora por su impacto sobre la diversidad de caracoles nativos, ya que desplaza y amenaza con desaparecer o por lo menos decrecer las poblaciones de moluscos nativos, debido a su alto potencial biótico, ser prolífica y a su tasa reproductiva alta. De esta forma, el objetivo de este trabajo fue evaluar la toxicidad aguda de las hojas de A. americana, F. andina y frutos de S. saponaria sobre M. tuberculata. El punto final de lectura fue la mortalidad del caracol M. tuberculataa 24 h de exposición, con recuperación en agua limpia a 24 h. Los valores de CL (Concentración letal media), NOEC (concentración de 50 efectos no observables) y LOEC (concentración más baja de efectos observables) presentaron la siguiente secuencia en orden de toxicidad decreciente: A. americana > F. andina > S. saponaria. El extracto acuoso de A. americana presentó los mejores efectos molusquicidas sobre M. tuberculata en comparación a las otras dos plantas empleadas.

Gastropod Diversity in the Pandayangan River, South Labuhanbatu Regency

This study aims to determine the diversity of Gastropods in the Pandayangan River, South Labuhanbatu Regency. Descriptive exploratory research was conducted at 3 stations from December to February 2021. Gastropod samples were taken from the sampling results at the time of the study in the Pandayangan River. Samples were taken from 3 stations with different characteristics, the gastropods were washed and documented. The identification process is carried out using the identification key of the Jutting book. The results obtained 7 types of Gastropods from 3 families of Thiaridae, Ampullariidae and Viviparidae, namely Brotia castula, Melanoides tuberculata, Melanoides punctate, Pomacea canaliculata, Pila polita, Pila ampullacea and Filopaludina sumatrensis. Gastropods catch 230 individuals. Station I found 40 individuals, Station II was found 80 individuals and Station III was found 110 individuals. Types of Brotia castula, Melanoides punctate, and Pomacea canaliculata were mostly found at Station II and Station III.

Malacofauna bentônica do Lago Igapó, Londrina (Paraná, Brasil), com ênfase na espécie invasora mexilhão-dourado Limnoperna fortunei (Dunker, 1857)

Objetivo: quantificar a abundância e a biomassa de moluscos bentônicos no Lago Igapó I, Londrina, Paraná, Brasil. Material e Métodos: foram realizadas duas coletas no Lago Igapó I, a primeira em junho de 2015 e a segunda em fevereiro de 2016. O substrato (incluindo os moluscos incrustados) foi amostrado utilizando um quadrante com área de 1 m2, onde 10 amostragens foram realizadas entre três pontos distintos do lago. Os moluscos capturados foram anestesiados e eutanasiados por superexposição ao gelo. Posteriormente, o material foi quantificado em abundância (n) e biomassa total (kg), e armazenado em tambores contendo formol 4% tamponado com carbonato de cálcio. Resultados: foram identificadas cinco espécies de moluscos, sendo três não nativas (Limnoperna fortunei, Corbicula fluminea e Melanoides tuberculata), uma nativa (Aylacostoma cf. tenuilabris) e um indivíduo do gênero Pomacea. Em ambas as coletas, L. fortunei compreendeu aproximadamente 90% da abundância e biomassa total. A partir da densidade média de L. fortunei e a área total do Lago Igapó I, estimou-se que a população total de mexilhões-dourados pode chegar a 633 milhões de indivíduos, correspondendo a 638 toneladas de biomassa. Conclusão: é evidente a dominância da espécie invasora L. fortunei no Lago Igapó I, onde esta pode causar diversos efeitos negativos, como alterações no ciclo de nutrientes, redução de espécies nativas, introdução de parasitos, bioacumulação de metais pesados na cadeia trófica, diminuição da qualidade da água para uso humano e obstrução de encanamentos com risco de alagamentos. Desta forma, recomenda-se uma imediata ação de manejo neste ambiente para retirada de indivíduos da espécie, com consequente redução de sua abundância.