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Introduction: The marine biodiversity is well known in some areas and for some marine ecosystems of the Pacific coast of Costa Rica. The marine sector of Área de Conservación Guanacaste, in the North Pacific of the country, is a priority area for conservation of marine and coastal biodiversity. Objective: Our aim was to increase the knowledge of marine biodiversity in a conservation priority site in Costa Rica and in poorly or scarcely studied marine ecosystems, such as rocky reefs and Sargassum beds, respectively. Methods: The study was conducted in Bahía Salinas and Golfo de Santa Elena in 2013. In January, four rocky reefs were visited; while in February three rocky reefs and one Sargassum bed were visited. We identified the macroinvertebrates and conspicuous fish species through underwater visual census methods (timed swim and band transects). The mean density of each species was estimated through band transects method. Results: A total of 25 invertebrates and 34 fish species were identified. We found a high number of species of invertebrates (23) and fish species (33) in rocky reefs, but few species on Sargassum beds (eight invertebrates and ten fish species). Species composition differed between marine ecosystems. Conclusions: Our study further evidence the limited knowledge of invertebrates and fish communities in these marine ecosystems in the North Pacific of Costa Rica. Considerably more surveys and field work are required to support management decisions that are backed by sound scientific knowledge.
Introducción: La biodiversidad marina es bien conocida en algunas áreas y para algunos ecosistemas marinos de la costa Pacífica de Costa Rica. El sector marino del Área de Conservación Guanacaste, en el Pacífico norte del país, es un área prioritaria para la conservación de la biodiversidad marina y costera. Objetivo: Nuestro objetivo fue el de incrementar el conocimiento de la biodiversidad marina en un sitio prioritario de conservación de Costa Rica y en ecosistemas marinos poco o nulamente estudiados, como son los arrecifes rocosos y mantos de Sargassum, respectivamente. Métodos: El estudio se realizó en Bahía Salinas y Golfo de Santa Elena en el 2013. En enero, cuatro arrecifes rocosos fueron visitados; mientras que en febrero tres arrecifes rocosos y un manto de Sargassum fueron visitados. Identificamos las especies de invertebrados y peces conspicuos a través métodos de censos visuales submarinos (buceos cronometrados y transectos de banda). La densidad promedio de cada especie se estimó mediante el método de transectos de banda. Resultados: Se registró un total de 25 invertebrados y 34 especies de peces. Encontramos un mayor número de especies de invertebrados (23) y peces (33) en los arrecifes rocosos, pero pocas especies en el manto de Sargassum (ocho especies de invertebrados y diez de peces). La composición de especies difirió entre ecosistemas marinos. Conclusiones: Nuestro estudio evidencia el limitado conocimiento de las comunidades de invertebrados y peces en estos ecosistemas marinos en el Pacífico Norte de Costa Rica. Considerablemente más encuestas y trabajo de campo son requeridos para apoyar decisiones de manejo que sean respaldados por conocimientos científicos solidos.
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Marine gastropods of the family Naticidaeare worldwide distributed and known for their unusual predatory habits. Due to their wide distribution, the naticids are worldwide studied and known like predators of intertidal bivalves. The present study demonstrates the predation of the naticid gastropod Natica marochiensison the bivalve Donax striatusin the northeastern region of Brazil.
Subject(s)
Animals , Bivalvia , Predatory Behavior , GastropodaABSTRACT
Abstract The rocky shores in Chile have a wide invertebrate species diversity, that include species with marked abundances in determined regions. The aim of the present study is to analyse the spatial distribution pattern in different marine invertebrate species in rocky shore of Araucania region, considering if these species have random, uniform or associated patterns, and extrapolate if these patterns have Poisson, binomial or negative binomial distribution respectively. The results revealed the presence mainly of gastropods molluscs that would graze on benthic algae, these species have mainly aggregated pattern that has a robust negative binomial distribution pattern. The obtained results agree with observations for marine benthic fauna that mentioned the presence of aggregated pattern, has negative binomial distribution. Other ecological topics about spatial distribution were discussed.
Resumo As costas rochosas no Chile têm uma ampla diversidade de espécies de invertebrados, que incluem espécies com abundância marcada em determinadas regiões. O objetivo do presente estudo é analisar o padrão de distribuição espacial em diferentes espécies de invertebrados marinhos na costa rochosa da região de Araucanía, considerando se essas espécies possuem padrões aleatórios, uniformes ou associados, e extrapolar se esses padrões possuem distribuição binomial de Poisson, binomial ou negativa. respectivamente. Os resultados revelaram a presença principalmente de moluscos gastrópodes que pastam em algas bentônicas, estas espécies têm principalmente agregado padrão que tem um padrão robusto de distribuição binomial negativa, padrão agregado de grupos, e a fauna de água doce que apresenta distribuição binomial negativa. Outros tópicos ecológicos sobre distribuição espacial foram discutidos.
Subject(s)
Animals , Gastropoda , Invertebrates , Chile , Ecosystem , Aquatic OrganismsABSTRACT
Introducción: El artículo "Moluscos de la Isla del Coco" publicado en la Revista del Colegio Superior de Señoritas (1935) es la traducción al español de una de las últimas obras de Paul Biolley Matthey (1862-1908), naturalista suizo radicado en Costa Rica, producto de una investigación malacológica efectuada en el marco de una expedición científica organizada por el Instituto Físico-Geográfico Nacional de Costa Rica (IFGN) en 1902, en una época en que el país reivindicaba su soberanía tanto en este territorio como en las zonas periféricas fronterizas. Objetivo: Analizar los aportes del artículo "Moluscos de la Isla del Coco" desde el enfoque de la Historia Social de la Ciencia. Métodos: La mayor parte de las investigaciones que han aplicado este enfoque en Costa Rica analizan procesos de institucionalización de disciplinas científicas. La metodología empleada en estos trabajos fue de gran utilidad para el análisis del artículo de Biolley, junto con la información de datos históricos proporcionados por otros textos sobre la Isla del Coco y el desarrollo de la investigación científica en Costa Rica desde una perspectiva temporal. Además, se hicieron tablas que sintetizan la clasificación de las especies y géneros estudiados por Biolley en la Isla del Coco para identificar su procedencia y el hábitat en el que viven. Resultados: Este estudio de Biolley constituye un texto de interés desde el punto de vista de la Historia Social de la Ciencia, debido a las descripciones que ofrece de las condiciones físicas del territorio de la Isla del Coco, de las diferentes especies de moluscos localizadas en ellas y al intercambio de información con científicos nacionales y extranjeros que evidencian la participación de Biolley en redes científicas. Conclusiones: Al analizar la información proporcionada por el artículo con los trabajos basados en el enfoque de la Historia Social de la Ciencia, se llegó a la conclusión que la recopilación de los datos de flora y de fauna permitió tener un mayor conocimiento de los recursos naturales de los territorios explorados, con el fin de colonizarlos e integrarlos a la dinámica económica del Valle Central de Costa Rica, sin embargo, los intentos para efectuar una colonización efectiva de la Isla del Coco fracasaron dada la distancia entre esta y el continente, además de las condiciones topográficas que impiden el establecimiento permanente de poblaciones humanas y sus actividades productivas.
Introduction: The paper "Moluscos de la Isla del Coco" (Mollusks of Cocos Island) published in the Revista del Colegio Superior de Señoritas (1935) is the translation to Spanish of one of the last works of Paul Biolley Matthey (1862-1908), Swiss naturalist that lived in Costa Rica. This article was one product of a malacological research carried out during a scientific expedition organized by the 'Instituto Físico-Geográfico Nacional de Costa Rica' (IFGN) in 1902 to Cocos Island, at a time when the country claimed its sovereignty both in this territory. Objective: To analyze the contributions of the article "Moluscos de la Isla del Coco" from the Social History of Science approach. Methods: Most of the researches that have applied this approach in Costa Rica analyze processes of institutionalization of scientific disciplines. The methodology used in these works was very useful for the analysis of the Biolley article, together with the information of historical data provided by other texts about Cocos Island and the development of scientific research in Costa Rica from a temporal perspective. In addition, tables were made to synthesize the classification of the species and genera studied by Biolley in Cocos Island to identify their provenance and the habitat in which they lived. Results: This study of Biolley constitutes a text of interest from the point of view of the Social History of Science, due to the descriptions it offers of the physical conditions of the territory of Cocos Island, of the different species of mollusks located in them and to the exchange of information with national and foreign scientists that show the participation of Biolley in scientific networks. Conclusions: The analysis of the information with the Social History of Science approach, concludes that the compilation of the flora and fauna permits a greater knowledge of the natural resources of the explored territories, in order to colonize them and integrate them into the economic dynamics of the Central Valley of Costa Rica. However, attempts colonize Cocos Island failed given the distance between this and the continent, in addition to the topographic conditions that prevent the permanent establishment of human populations and their productive activities.
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Introducción: El bentos constituye un eficiente indicador de disturbios ambientales, de biodiversidad y de dinámica trófica. En Cuba, los moluscos bentónicos han sido reportados como el principal alimento de la langosta Panulirus argus. Objetivos: Estimar variaciones espacio-temporales en la comunidad bentónica de fondos blandos del golfo de Batabanó, e inferir, haciendo énfasis en los moluscos, el efecto de tales variaciones en la disponibilidad de alimento para las langostas. Métodos: Se realizó un análisis histórico de las variaciones en la densidad y biomasa de megazoobentos (organismos ≥ 4 mm) y particularmente de moluscos megazoobentónicos, tomando como referencia los estudios realizados desde 1990 (muestreos del año 1983) y datos actuales (2007-2018) registrados in situ mediante metodologías comparables. Resultados: Se encontró que tanto la densidad como la biomasa eran significativamente mayores al final del pasado siglo y muestran tendencia a disminuir gradualmente hacia la actualidad. Respecto a los valores reportados en 1983, la densidad de organismos mostró un decrecimiento del 73 %, sin embargo, la biomasa experimentó una disminución aún mayor (86 %). Las áreas de mayor densidad y biomasa, tanto de bentos como de moluscos, han variado respecto a lo reportado para 1983 y actualmente se ubican hacia el centro del golfo. A pesar de ello, los bivalvos continúan estando mejor representados que los gastrópodos. En general, los moluscos mostraron un significativo decrecimiento (55 % y 88 % respectivamente). Conclusiones: Se corroboró el deterioro de la comunidad bentónica en las áreas pesqueras del golfo de Batabanó y se demostró, basado en el megazoobentos, que la malacofauna puede utilizarse como un indicador fiable de los parámetros generales de la comunidad bentónica de fondos blandos. Se estimó que la disponibilidad de alimento para las langostas ha disminuido en un 55.6 % respecto a 1983, lo cual, unido a las variaciones espaciales del megazoobentos, puede contribuir a explicar los actuales cambios en la abundancia y distribución de las langostas.
Introduction: Benthos is an efficient indicator of environmental disturbances, biodiversity and trophic dynamics. In Cuba, benthic mollusks have been reported as the main food for the lobster Panulirus argus. Objectives: To estimate spatio-temporal variations in the soft-bottom benthic community of the Gulf of Batabanó, and to infer, with emphasis on mollusks, the effect of such variations on the availability of food for spiny lobsters. Methods: A historical analysis of the variations in the density and biomass of megazoobenthos (organisms ≥ 4 mm) and particularly of megazoobenthic mollusks was carried out, taking as a reference the studies published in 1990 (with samples from 1983) and recent data (2007-2018) recorded on site using comparable methodologies based on sediment drags. Abundance was given as density (ind/m2) and biomass in g/m2. Results: It was found that both the density and the biomass were significantly higher at the end of the last century and show a tendency to gradually decrease towards recent times. Regarding the values reported in 1983, the density of organisms showed a decrease of 73 %, however, the biomass experienced an even greater decrease (86 %). The areas with the highest density and biomass, both benthos and mollusks, have varied from 1983 and are currently located towards the center of the gulf. Despite this, bivalves continue to be better represented than gastropods. In general, mollusks showed a significant decrease (55 % and 88 % respectively). Conclusions: The deterioration of the benthic community in the fishing areas of the Gulf of Batabanó was corroborated and it was demonstrated, based on megazoobenthos, that malacofauna can be used as a reliable indicator of the general parameters of the soft-bottom benthic community. The availability of food for lobsters have decreased 55.6 % compared to 1983. This could help to explain the current changes in the abundance, distribution and nutritional condition of lobsters, which could also be related to the recent megazoobenthos variations.
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Marine organisms make up approximately half of the total global biodiversity, with the Molluscacontaining the second largest number of species, including snails and bivalves. The marine environment is highly competitive, hostile and aggressive, which has led to the production of specific and potent bioactive compounds by the mollusca and their associated microorganisms, in a bid to protect themselves and ensure their survival. A diverse array of bioactive compounds can be isolated from the extracts of marine molluscs of which linear, cyclic, and conjugated peptides and depsipeptides form some of themost important bioactive compounds that have been well characterized and some of have already reached clinical trials or been approved for use as therapeutic agents and supplements. This review highlights some of the bioactive peptides that have been obtained from marine molluscs as well the challenges facing bioprospecting of valuable peptides from marine mollusc sources.
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Introducción: en el paisaje epidemiológico de la fascioliasis humana, dos aspectos son de fundamental importancia: a) presencia de hospederos definitivos (especialmente ganado bovino y humanos) parasitados con adultos del tremátodo y; b) presencia de hospederos intermediarios invertebrados, moluscos de la familia Lymnaeidae, en los que se desarrollan los estadios larvarios, además de plantas acuáticas de consumo humano. Material y métodos: con el objetivo de prevenir brotes de fascioliasis humana mediante la correcta identificación de aspectos de interés epidemiológico, un humedal fue seleccionado en el sector de Palo Blanco, municipio de Jarabacoa, provincia de La Vega, en el cual se realizó un estudio malacológico en octubre de 2016, en busca de especies de moluscos limneidos e hidrófitos asociados. En el laboratorio se obtuvieron los índices de infección natural y experimental a Fasciola hepatica. Resultados: se identificó el limneido Pseudosuccinea columella, en proporciones de 250 especímenes por persona/hora. El vegetal predominante fue el berro (Nasturtiun officinale), cultivado comercialmente en tres cuadrantes del humedal y en el otro cuadrante se observaron bovinos pastando. El índice de infección experimental de los moluscos fue de 94 % a la cepa simpátrica de F. hepatica de Dajabón; no se encontraron moluscos parasitados naturalmente. Conclusiones: Pseudosuccinea columella debe considerarse como un molusco de relevancia epidemiológica en la transmisión de la fascioliasis en República Dominicana, a tenor de su dispersión y elevado índice de infección experimental obtenido en el presente estudio
Introduction: in the epidemiological landscape of human fascioliasis, two aspects are of fundamental importance: a) presence of definite hosts (especially cattle and humans) parasitized with trematode adults and b) presence of invertebrate intermediate hosts, mollusks of the family Lymnaeidae, in which larval stages develop, in addition to aquatic plants for human consumption. Material and methods: in order to prevent outbreaks of human fascioliasis by correctly identifying aspects of epidemiological interest, a wetland was selected in the sector of Palo Blanco, municipality of Jarabacoa, province of La Vega, in which a malacological study was carried out in October 2016, in search of limneid mollusk species and associated hydrophytes. Natural and experimental infection rates to Fasciola hepaticawere obtained in the laboratory. Results: the lymnaeid Pseudosuccinea columella was identified, in proportions of 250 specimens collected per person/hour. The predominant vegetable was the watercress (Nasturtiun officinale), commercially cultivated in three quadrants of the wetland and in the other quadrant were observed cattle grazing. The rate of experimental infection of mollusks was 94 % to the sympatric strain of F. hepatica of Dajabón; no naturally parasitized mollusks were found. Conclusions: Pseudosuccinea columella should be considered as a mollusk of epidemiological relevance in the transmission of fascioliasis in the Dominican Republic, due to its dispersion and high rate of experimental infection obtained in the present study
Subject(s)
Fascioliasis , Intestinal Diseases, Parasitic , Dominican RepublicABSTRACT
Objetive: To confirm the presence of Angiostrongylus cantonensis in Lissachatina fulica individuals in Colombia. Methods: 19 individuals of L. fulica were collected in the city of Buenaventura, Valle del Cauca, Colombia. Lung tissue was extracted and two analysis methods were used: visual identification by histological observation, and identification through conventional and real-time PCR. The A. cantonensis detection rate was established taking into account each of the analysis techniques used. Results: Presence of A. cantonensis was confirmed in the lung tissue of L. fulica specimens collected in the city of Buenaventura, Valle del Cauca, Colombia. The detection rate based on visual identification through histological analysis was 89%, whereas it was 95% using conventional PCR, and 100% using real-time PCR. Conclusion: This study confirmed for the first time the presence of A. cantonensis associated with L. fulica specimens in Colombia. Therefore, eosinophilic meningitis could be considered an emerging disease in Colombia.
Objetivo: confirmar la presencia de Angiostrongylus cantonensis en individuos de Lissachatina fulica en Colombia. Materiales y métodos: se recolectaron 19 individuos de L. fulica en la ciudad de Buenaventura, Valle del Cauca, Colombia. Se extrajo el tejido pumonar y se utilizaron dos métodos de análisis: identificación visual por observación histológica e identificación a través de PCR convencional y en tiempo real. La tasa de detección de A. cantonensis fue establecida para cada una de las técnicas de análisis utilizadas. Resultados: se confirmó la presencia de A. cantonensis en el tejido pulmonar de los especímenes de L. fulica recolectados en la ciudad de Buenaventura, Valle del Cauca, Colombia. La tasa de detección alcanzanda a través de la técnica de identificación visual mediante análisis histológico fue del 89%, mientras que usando la técnica de PCR convencional fue del 95% y de PCR en tiempo real fue del 100%. Conclusión: este estudio confirma por primera vez la presencia de A. cantonensis asociado a especímenes de L. fulica en Colombia. Por lo tanto, se sugiere que la meningitis eosinofílica sea propuesta como una enfermedad emergente en Colombia.
Subject(s)
Humans , Snails , Angiostrongylus cantonensis , Meningitis , Colombia , Disease Vectors , Real-Time Polymerase Chain Reaction , Viral Zoonoses , Lung , Meningoencephalitis , MolluscaABSTRACT
Abstract This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis (Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.
Resumo Este trabalho descreve a morfologia ultraestrutural detalhada do fagócito encarcerando um oocisto de Nematopsis (Apicomplexa) encontrado em Crassostrea rhizophorae, na cidade de Maceió (AL), Brasil. Os hospedeiros muito infectados apresentavam valvas entreabertas com retração fraca e lenta dos músculos abdutores. Número variável de oócitos de forma elipsoide, isolados e ou agrupados foi encontrado entre as miofibrilas do músculo abdutor. Cada oocisto estava encarcerado num vacúolo parasitóforo do fagócito uninucleado do hospedeiro. Os oocistos eram compostos por uma parede densa contendo um esporozoíto vermiforme uninucleado. A parede dos oocistos finos era composta de material electron-lucente homogêneo formado por três camadas de espessura igual, possuindo um orifício circular - micrópila, obstruída pelo opérculo. Os oocistos apresentavam morfologia elipsoide, sua parede era circundada por uma complexa rede de numerosas microfibrilas. Detalhes de valor taxonômico importantes foram visualizados tais como: a organização ultraestrutural da parede do oocisto e a organização da micrópila e do opérculo, além das microfibrilas que se projetam da parede do oocisto, estrutura apenas observada em microscopia eletrônica de transmissão (MET) e que pode auxiliar na identificação da espécie. Contudo, para esclarecer a posição sistemática da maioria das espécies relatadas do gênero Nematopsis é importante prosseguir com as análises genéticas.
Subject(s)
Animals , Phagocytes/ultrastructure , Apicomplexa/ultrastructure , Oocysts/ultrastructure , Crassostrea/parasitology , Brazil , Apicomplexa/isolation & purification , Microscopy, Electron, TransmissionABSTRACT
Entre febrero de 2010 y mayo de 2014 se realizaron 22 evaluaciones en Pisco y 16 en Sechura; ambas áreas importantes en Perú para la extracción de moluscos y maricultura. La incidencia de Vibrio en el agua de mar fue monitoreada durante las floraciones de algas y en épocas normales. Se midieron parámetros ambientales tales como temperatura y nutrientes. En Sechura, Pseudo-nitzschia seriata y Protoperidinium depressum causaron floraciones de algas y fueron dominantes durante todo el período de evaluación. Las temperaturas en esta zona oscilaron entre 21.8 y 25.3 °C. En Pisco, la concentración Akashiwo sanguinea, Messodinium rubrum y Prorocentrum mínimum y el dinoflagelado Cochlodinium polikrykoides fueron los más frecuentes. Las floraciones de algas nocivas ocurrieron cuando las temperaturas estaban entre 17.1 y 23.3 °C, concentraciones de fosfatos que oscilaban entre 1.22 - 6.85 μM y nitratos 0.15 - 7.85 μM. En mayo de 2012, el dinoflagelado Alexandrium peruvianum causó una floración algal, bajo temperaturas de 18.0 a 23.2 °C, valores de fosfato de 0.73 a 11.56 μM y nitratos de 0.76 a 9.81 μM. Los coliformes fueron bajos < 2 - 23 MPN/100 mL, en ambas bahías durante todo el período de estudio. Vibrio alginolyticus fue la especie dominante. Mientras que V. vulnificus y V. parahaemolyticus se detectaron en Pisco, donde las temperaturas del mar comúnmente son mayores y los casos de infecciones graves por ingestión de mariscos se han asociado con el patógeno V. parahaemolyticus.
Between February 2010 and May 2014, 22 surveys in Pisco and 16 in Sechura were conducted; both are major areas for shellfish production and mariculture in Peru. The incidence of Vibrio in seawater was monitored during algal blooms and in their absence. Environmental parameters such as temperature and nutrients were measured. In Sechura, Pseudo-nitzschia seriata and Protoperidinium depressum caused algal blooms and were dominant throughout the evaluation period. The temperatures in this area ranged from 21.8 to 25.3 °C. In Pisco, the harmful algal bloom-forming Akashiwo sanguinea, Messodinium rubrum, and Prorocentrum minimum and the dinoflagellate Cochlodinium polikrykoides were most prevalent. Harmful algal blooms occurred when temperatures were between 17.1 and 23.3 °C, with phosphates ranging 1.22 - 6.85 μM and nitrates 0.15 - 7.85 μM. In May 2012, the dinoflagellate Alexandrium peruvianum caused an algal bloom, with temperatures ranging 18.0 to 23.2 °C, phosphate values from 0.73 to 11.56 μM, and nitrates from 0.76 to 9.81 μM. Coliforms were low, < 2 - 23 MPN/100 ml, in both bays throughout the study period. Vibrio alginolyticus was the dominant Vibrio spp. predominated in both bays, while V. vulnificus and V. parahaemolyticus were detected in Pisco, where warmer sea temperatures are common and severe infections cases by seafood ingestion has been associated with a pathogen V. parahaemolyticus.
ABSTRACT
Abstract The rocky shores in Chile have a wide invertebrate species diversity, that include species with marked abundances in determined regions. The aim of the present study is to analyse the spatial distribution pattern in different marine invertebrate species in rocky shore of Araucania region, considering if these species have random, uniform or associated patterns, and extrapolate if these patterns have Poisson, binomial or negative binomial distribution respectively. The results revealed the presence mainly of gastropods molluscs that would graze on benthic algae, these species have mainly aggregated pattern that has a robust negative binomial distribution pattern. The obtained results agree with observations for marine benthic fauna that mentioned the presence of aggregated pattern, has negative binomial distribution. Other ecological topics about spatial distribution were discussed.
Resumo As costas rochosas no Chile têm uma ampla diversidade de espécies de invertebrados, que incluem espécies com abundância marcada em determinadas regiões. O objetivo do presente estudo é analisar o padrão de distribuição espacial em diferentes espécies de invertebrados marinhos na costa rochosa da região de Araucanía, considerando se essas espécies possuem padrões aleatórios, uniformes ou associados, e extrapolar se esses padrões possuem distribuição binomial de Poisson, binomial ou negativa. respectivamente. Os resultados revelaram a presença principalmente de moluscos gastrópodes que pastam em algas bentônicas, estas espécies têm principalmente agregado padrão que tem um padrão robusto de distribuição binomial negativa, padrão agregado de grupos, e a fauna de água doce que apresenta distribuição binomial negativa. Outros tópicos ecológicos sobre distribuição espacial foram discutidos.
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El presente trabajo describe la distribución geográfica actual de las principales especies de caracoles de agua dulce incriminadas como hospedadoras intermediarias de Schistosoma mansoni (4 especies de Biomphalaria), Fasciola hepatica (4 especies de Galba y Pseudosuccinea columella) y Paragonimus sp. (Aroapyrgus vivens) en Venezuela. Adicionalmente, se discute el status epidemiológico así como el hábitat de ocurrencia de cada una de estas especies, a fin de brindar información base para la vigilancia, manejo y control de los hospedadores intermediarios que participan en los ciclos vitales de los agentes causales de la esquistosomiasis, fascioliasis y paragonimiasis, que constituyen enfermedades desatendidas actualmente en Venezuela.
This study describes the current distribution patterns of the main species of freshwater mollusks incriminated as intermediate hosts of Schistosoma mansoni (Biomphalaria, 4 species), Fasciola hepatica (Galba, 4 species and Pseudosuccinea columella), and Paragonimus sp. (Aroapyrgus vivens) in Venezuela. Additionally, the epidemiological status and the main aquatic habitats of each species are discussed in order to bring basic information to help the surveillance and control of these neglected tropical diseases in Venezuela.
ABSTRACT
AbstractHypoxia is the depletion of dissolved oxygen below 2 mg O2/L. Relatively few studies on hypoxia and its effects on benthic macrofauna have been done in tropical marine ecosystems. This study describes the temporal response of the water column, sediments and macrofauna to seasonal hypoxia in a semi-enclosed bay (Cienfuegos, Caribbean Sea). The Calisito site was sampled monthly from June 2010 until February 2012, yielding 21 sampling times. At each sampling event water and sediment samples were collected for measuring the abiotic variables (temperature, salinity, dissolved oxygen, nutrients, redox potential discontinuity, silt/clay and organic matter content) and macrofauna (abundance and species richness). Temperature and surface salinity followed a typical temporal pattern during the summer/rainy and the winter/dry periods. Salinity stratification occurred in the rainy period, lasting three months in 2010 and six months in 2011. The bottom water dissolved oxygen indicated hypoxic and anoxic events during the wet periods of 2010 and 2011 associated with salinity stratification, low hydrodynamics and oxidation of the accumulated organic matter. Over the study period, 817 individuals were collected and identified. Polychaetes were the dominant group in terms of abundance (57 % of total) followed by mollusks (41%). Hypoxia (and occasionally anoxia) caused strong deleterious effects on the abundance and species richness of macrofaunal communities in the study site. The most abundant polychaetes were opportunistic species with high tolerance to hypoxic conditions: Prionospio steenstrupi, Polydora sp.and Paraprionospio pinnata. Most of them colonized relatively fast once hypoxia ended. Persistent species such as Caecum pulchellum and Parvanachis obesa were present during hypoxia with fluctuating densities and apparently recover to higher abundances when normoxic conditions are re-established. Macoma tenta and Tellina consobrina colonized approximately 1-2 months later than the first polychaete peak during normoxia. Probably, the deleterious effects of hypoxia on the macrofauna were intensified by negative interspecific relationships such as competition by suitable space and predation. The recolonization of macrofauna depended possibly on local transport by currents within the bay because the connection with the Caribbean Sea is relatively limited. In summary, seasonal hypoxia in Cienfuegos Bay influences the water and sediment geochemistry and reduces both the abundance and diversity of macrofauna.
ResumenLa hipoxia es la disminución del oxígeno disuelto por debajo de 2 mg O2/L. Relativamente pocos estudios sobre la hipoxia y sus efectos en la macrofauna bentónica han sido realizados en ecosistemas marinos tropicales. Este estudio describe la respuesta temporal de la columna de agua, los sedimentos y la macrofauna a la hipoxia estacional en una bahía semicerrada en Cienfuegos, Mar Caribe. La estación de Calisito fue muestreada mensualmente de Junio 2010 a Febrero 2012, resultando en 21 eventos de muestreo. En cada oportunidad se recolectaron muestras de agua y sedimento para la medición de las variables abióticas (temperatura, salinidad, oxígeno disuelto, discontinuidad del potencial redox, contenido de limo/arcilla y materia orgánica) y macrofauna (abundancia y riqueza de especies). La temperatura y la salinidad superficial presentaron un patrón temporal típico durante los periodos de verano/ lluvia e invierno/seca. Ocurrió estratificación por salinidad en el periodo lluvioso, que duró tres meses en 2010 y seis en 2011. El oxígeno disuelto de fondo indicó eventos de hipoxia y anoxia durante los periodos lluviosos de 2010 y 2011 asociados con la estratificación de la columna de agua, la hidrodinámica lenta y la oxidación de la materia orgánica acumulada. Esto causó efectos deletéreos en la abundancia y diversidad de la macrofauna. Los poliquetos más abundantes fueron especies oportunistas con alta tolerancia a condiciones hipóxicas: Prionospio steenstrupi, Polydora sp. y Paraprionospio pinnata. La mayoría de estos colonizaron relativamente rápido una vez que terminó la hipoxia. Especies persistentes como Caecum pulchellum y Parvanachis obesa estuvieron presentes durante la hipoxia con densidades fluctuantes y aparentemente recuperaron sus abundancias cuando las condiciones normóxicas fueron re-establecidas. Macoma tenta y Tellina consobrina colonizaron 1-2 meses después que el primer pico de poliquetos durante la normoxia.Probablemente, los efectos deletéreos de la hipoxia en la macrofauna fueron intensificados por relaciones interespecíficas negativas como la competencia por espacio y la depredación. La recolonización de la macrofauna dependió probablemente del transporte local por las corrientes dentro de la bahía pues la conexión con el mar Caribe es relativamente limitada. En resumen, la hipoxia estacional en la bahía de Cienfuegos influencia la geoquímica del agua y los sedimentos y reduce la abundancia y diversidad de la macrofauna.
Subject(s)
Animals , Oxygen/analysis , Environmental Monitoring , Biodiversity , Invertebrates/classification , Seasons , Population Density , Geologic Sediments , Cuba , EutrophicationABSTRACT
Se llevó a cabo un inventario de moluscos en la zona de Boquerones, Ciego de Ávila, Cuba. Se estudiaron los índices de biodiversidad por formación vegetal, siendo estas: Bosque Siempreverde Mesofilo, Bosque Semideciduo Mesófilo y Complejo de Vegetación de Mogote. Las familias mejor representadas fueron Helicinidae, Annularidae, Urocoptidae y Subulinidae, teniendo el 97.6% de las especies algún grado de endemismo nacional y siendo de estas el 45.24% endémicos locales. La especie más ampliamente distribuida fue Farcimen camaguayanum Torre & Bartsch 1941 y la más rara fue Euclastaria euclasta Shuttleworth 1852. Los valores más altos de biodiversidad se observaron en el Complejo de Vegetación de Mogote siendo de 2.856 según el índice de Shannon-Wienner (H´). No se aprecian hasta el momento eventos de extinción de especies pero no se descartan para el futuro debido a un declive en las precipitaciones locales en los últimos 15 años así como a actividades antrópicas como la agricultura y el turismo local.
A census of mollusks in Boquerones, Ciego de Avila, Cuba was carried out. Biodiversity index were studied by vegetal formation, which are: Evergreen Forest, Semideciduous Forest and Mogote Vegetation Complex. The families best represented were Helicinidae, Annularidae, Urocoptidae and Subulinidae, taking the 97.6% of the species some degree of national endemism and being the 45.24% of these local endemic. The most widely distributed species was Farcimen camaguayanum Torre & Bartsch 1941 and the rarest was Euclastaria euclasta Shuttleworth 1852. The highest biodiversity values were observed in the Mogote Vegetation Complex being of 2,856 according to Shannon-Wiener (H´) index. So far species extinction events are not seen but not discarded for the future due to a decline in local rainfall during the last 15 years as well as human activities such as agriculture and local tourism.
ABSTRACT
La Mancha lagoon is connected to the Gulf of Mexico through an estuarine ephemeral inlet, a sand bar, which opens during the rainy season and closes during the late fall and the winter storm season. As the lagoon fills up with the permanent stream flow into its Southern part, the water level increases and the sand bar opens up, releasing huge volumes of water into the ocean and leaving the previously flooded intertidal zone exposed to drying. In this study, we described the spatial and temporal variations of structure and composition of the community living on the surface of red mangrove prop roots, related to the hydrodynamic of the estuarine inlet. Four red mangrove prop roots were collected every three months, over an annual period, at ten sampling stations. Water temperature, salinity, dissolved oxygen, water depth and transparency were also measured at each sampling event. To describe the identity, abundance, biomass, and specific richness of epibiont coverage on the prop roots, measurements were taken at 10cm intervals (herein called horizons). A total of 59 632 specimens and a total biomass of 172g/cm2 were registered, and a maximum of eleven horizons presented at least one species of epibionts. Two species of polychaetes, 12 of mollusks and 14 of crustaceans were identified, with Mytilopsis leucophaeata as the most abundant, Ficopomatus miamiensis as the most common and Crassostrea rhizophorae with the highest contribution in biomass. Sampling effort was assessed using species accumulation curves, resulting that the efficiency was, in general, greater than 90% of the richness predicted by asymptotic models. The hydrodynamics of the estuarine inlet had a great influence on the environmental conditions of the lagoon and on the spatial and temporal variation of the epibiont community: (a) when the inlet is open, there is a North-South gradient in environmental parameters (b) when the inlet is closed and the water level increases, the epibionts especially the pioneer species F. miamiensis, occupied the highest horizons of prop roots, and (c) the abundance, biomass and richness of epibionts increased towards the deeper and less saline Southern part of the lagoon, as well as on permanently submerged horizons, and during the seasonal closure of the inlet. Variations in depth are determined by the hydrodynamic behavior of the estuarine inlet, suggesting that these factors are major biodiversity drivers of the epibiont community at La Mancha. Rev. Biol. Trop. 62 (4): 1309-1330. Epub 2014 December 01.
La laguna de La Mancha está conectada al Golfo de México a través de una boca estuarina efímera, una barra arenosa, la cual se abre durante la época de lluvias y se cierra durante el otoño y la temporada de vientos invernales. Cuando la laguna se llena con la entrada de agua proveniente de un arroyo permanente, ubicado en la parte sur, el nivel del agua se incrementa y la barra arenosa se abre, descargando grandes volúmenes de agua hacia el océano y dejando expuesta a la desecación la zona intermareal previamente inundada. En este estudio, se describen las variaciones espacio-temporales de la estructura y composición de la comunidad de epibiontes que vive en la superficie de las raíces del mangle rojo,y su relación con la dinámica hidrológica de la boca estuarina. Se recolectaron cuatro raíces trimestralmente, durante un año, en diez estaciones de muestreo. También se midió la temperatura del agua, salinidad, oxígeno disuelto, profundidad y transparencia en cada muestreo. Se determinó la abundancia, la biomasa y la riqueza específica, a lo largo de las raíces en segmentos verticales de 10cm llamados horizontes. Se registraron un total de 59 632 especímenes y una biomasa total de 172g/cm2, y un máximo de once horizontes presentaron al menos una especie de epibionte. Se identificaron dos especies de poliquetos, 12 de moluscos y 14 de crustáceos, siendo Mytilopsis leucophaeata la más abundante, Ficopomatus miamiensis la más común y Crassostrea rhizophorae la de mayor contribución a la biomasa. Se evaluó la eficiencia del muestreo mediante curvas de acumulación de especies, resultando que la eficiencia fue, en general, >90% de la riqueza estimada por modelos asintóticos. La hidrodinámica de la boca estuarina tuvo gran influencia en las condiciones ambientales de la laguna y en las variaciones espacio-temporales de la comunidad de epibiontes: (a) cuando la boca estuarina está cerrada son más claros los gradientes ambientales norte-sur, (b) cuando la boca estuarina se cierra y el nivel de inundación se incrementa, los epibiontes, especialmente la especie pionera F. miamiensis, ocupan los horizontes más altos de las raíces, (c) la abundancia, biomasa y riqueza específica de los epibiontes se incrementó hacia las partes más profundas del sur de la laguna, así como en los horizontes permanentemente inundados, y durante el cierre estacional de la boca estuarina. Las variaciones en la profundidad dependen de la dinámica de la boca estuarina, sugiriendo que estos factores son los principales parámetros que estructuran a la comunidad de epibiontes de La Mancha.
Subject(s)
Animals , Ecosystem , Invertebrates/classification , Rhizophoraceae/classification , Biomass , Mexico , Population Density , Population Dynamics , Seasons , Spatio-Temporal AnalysisABSTRACT
Mollusks are some of the most important, abundant and diverse organisms inhabiting not only aquatic ecosystems, but also terrestrial environments. Recently, they have been used for bioremediation of aquaculture effluents; nevertheless, for that purpose it is necessary to analyze the capacity of a particular species. In this context, an experimental investigation was developed to evaluate the performance of two bivalves C. gnidia and D. ponderosa, collected from areas with or without shrimp aquaculture effluents. For this, the filtration capacity (as clearance rate) as well as the oxygen consumption and ammonia excretion rates were measured following standard methods. The clearance rate was significantly higher for D. ponderosa from impacted areas, when com- pared to C. gnidia, from both areas. Contrarily, the oxygen consumption was greater for C. gnidia from impacted areas compared to D. ponderosa from both areas. The same tendency was observed for the ammonia excretion with the highest rates observed for C. gnidia from impacted areas, whereas no differences were observed among D. ponderosa from both areas. The results suggest that both species developed different strategies to thrive and survive under the impacted conditions; D. ponderosa improved its filtration efficiency, while C. gnidia modified its oxygen consumption and ammonia excretion. We concluded that both species, and particularly D. ponderosa, can be used for bioremediation purposes.
Los moluscos son algunos de los organismos más importantes, abundantes y diversos que habitan no solo ecosistemas acuáticos sino también terrestres. Recientemente ellos han sido utilizados para la biorremediación de efluentes acuícolas; para este propósito, es necesario conocer la capacidad de especies particulares que funcionan como biorremediadores. En este contexto, se evaluó la eficiencia de filtración (medida como tasa de clarificación), así como las tasas de consumo de oxígeno y excreción amoniacal en los bivalvos D. pon- derosa y C. gnidia recolectados en áreas impactadas y no impactadas por efluentes de granjas camaroneras. La tasa de clarificación fue mayor para D. ponderosa procedente de áreas impactadas, comparada con la de C. fluctifraga en las dos áreas de recolecta. Contrariamente, la tasa de consumo de oxígeno fue superior en C. gnidia en las áreas impactadas al compararla con organismos de áreas no impactadas y con D. ponderosa de las dos áreas de recolecta. La tasa de excreción amoniacal siguió una tendencia similar con valores más altos para C. gnidia en áreas impactadas, mientras que no se observaron diferencias para D. ponderosa entre las áreas de recolecta. Los resultados sugieren que ambas especies desarrollan diferentes estrategias para adaptarse y sobrevivir bajo condiciones de impacto; D. ponderosa mejora su eficiencia de filtración y C. gnidia modifica su consumo de oxígeno y excreción amoniacal. Se concluye que ambas especies, pero sobre todo D. ponderosa pueden ser utilizadas con propósitos de biorremediación.
Subject(s)
Animals , Ammonium Compounds/metabolism , Aquaculture/methods , Bivalvia/physiology , Oxygen Consumption/physiology , Penaeidae/growth & development , Biodegradation, Environmental , Bivalvia/classification , Water Purification/methodsABSTRACT
La plasticidad de los caracteres conquiliológicos ha conllevado a diversas descripciones erróneas y a la acumulación de sinonimias lo cual ha dificultado la discriminación entre especies. El género de moluscos terrestres Megalobulimus es un ejemplo de esta problemática. Dentro de éste se encuentra Megalobulimus leucostoma (Sowerby, 1835), que presenta tres subespecies las cuales no se logran diferenciar correctamente a partir de sus descripciones originales. El presente estudio busca discriminar a las subespecies de Megalobulimus leucostoma a partir del análisis morfométrico y de distribución. Ambos análisis establecen diferencias sustanciales entre M. l. leucostoma y M. l. lacunosus que no soportarían el estatus de subespecie de esta última. Megalobulimus leucostoma weyrauchi se ubica dentro de la gran gama de variabilidad conquiliológica de M. l. leucostoma y sus datos de distribución lo ubican en simpatría con la misma por lo cual su estatus como subespecie no estaría soportado, y podría considerarse como parte de M. l. leucostoma.
Plasticity of conchological characters had led to erroneous descriptions and the accumulation of synonyms making difficult the discrimination among species. The land snail genus Megalobulimus is an example of this problem. Megalobulimus leucostoma (Sowerby, 1835) has three subspecies which are difficult to differentiate by using the original descriptions. The aim of this paper is to discriminate among the subspecies of M. leucostoma by using morphometric and distribution analyses. Both provide substantial differences between M. l. leucostoma and M. l lacunosus that would not support the subspecies status of the former. Megalobulimus leucostoma weyrauchi fits into the great conchological variability of M. l. leucostoma; also the sympatric status between these two subspecies would not support the subspecies status of the former, and M. l. weyrauchi should be considered as part of M. l. leucostoma.
ABSTRACT
Introduction Schistosomiasis is a parasitic disease of public health concern in Brazil, and the construction of hydroelectric dams, in addition to increasing permanent human settlement and tourism, has created conditions suitable for the establishment of mollusks that can transmit schistosomiasis. Such areas require a number of actions to prevent the establishment of schistosomiasis. This paper reports on a freshwater malacological survey carried out in the geographical area of the Manso Power Plant. Methods Mollusks were collected in 18 municipalities in the State of Mato Grosso between February 2002 and February 2004 (qualitative study) and from April 2009 to February 2011 (quantitative study). Results Thirty-one species of mollusks were collected, including newly recorded species (Antillorbis nordestensis and Burnupia ingae). In addition, the geographic distributions of known species, including Biomphalaria straminea, a snail vector of Schistosoma mansoni, were expanded. A total of 4,507 specimens were collected in the APM Manso reservoir (Usina Hidrelétrica de Aproveitamento Múltiplo de Manso) during the quantitative study, and Biomphalaria amazonica was found in six of the 10 localities analyzed. The Afroasiatic species Melanoides tuberculata, introduced after February 2009, was the dominant species (relative abundance 94.96%). Conclusions The study area is epidemiologically important due to the occurrence of B. straminea and B. amazonica, which are vectors of schistosomiasis, and M. tuberculata, a snail host of Centrocestus formosanus, which is responsible for centrocestiasis transmission. Observations of M. tuberculata and the exotic freshwater clams Corbicula fluminea and Corbicula largillierti raise concerns about biodiversity. .
Subject(s)
Animals , Disease Vectors/classification , Fresh Water/parasitology , Power Plants , Schistosoma mansoni , Snails/classification , Snails/parasitology , Brazil , Population Density , Seasons , Schistosomiasis mansoni/transmissionABSTRACT
The geographical distribution of the family Limacinidae in the Northeastern coast of Brazil was analyzed by taking into account the most relevant ecological aspects, aiming to increase the knowledge about the Family. The material was collected during the 4th Oceanographic Expedition of the REVIZEE program (Assessment of the Sustainable Potential of Living Resources in the Exclusive Economic Zone - Avaliação do Potencial Sustentável de Recursos Vivos da Zona Econômica Exclusiva), in the months from September to December 2000. The studied area is located between 00°46'45"N and 13°53'45"S and between 29°15'40"W and 39°49'42"W, where six trips were performed, totaling 123 stations. The samples were collected using a bongo net (300- and 500-µm mesh size and net mouths of 60 cm in diameter) coupled with a digital flowmeter in oblique hauls from a depth of 0 to 200 m. For this study, the organisms retained in the 300-µm mesh were considered. On board the ship, the samples were placed in plastic containers, labeled, and fixed in 4% formaldehyde buffered with sodium tetraborate. In the laboratory, the samples were analyzed on a "Bogorov" tray under a binocular stereomicroscope. A total of 5655 individuals of the family Limacinidae were examined and were distributed as follows: 3 genera and 5 species. Representatives of the family Limacinidae were observed at high temperatures and salinities and were thus characterized as tropical and euhaline.Heliconoides inflatus was the species with the greatest abundance and frequency. Limacina lesueurii proved to be a rare, infrequently observed species. Limacina trochiformis andL. bulimoides were not abundant or frequent.Limacina lesueurii and L. bulimoides were recorded in neritic waters for the first time; this was also the first record ofL. lesueurii in the waters of Northeastern Brazil.Limacina trochiformis and L. bulimoidesexhibited wide distributions, although they were neither very frequently observed nor abundant. The distribution of Thielea helicoideswas restricted to oceanic waters. A correlation between Limacina bulimoides, Heliconoides inflatus, Thielea helicoides, and L. lesueurii was observed because they coexisted in the same niche.
A distribuição geográfica da família Limacinidae na costa do Nordeste brasileiro, foi analisada levando em consideração os aspectos ecológicos mais relevantes, objetivando a ampliação do conhecimento sobre a família. O material foi coletado durante a IV Expedição Oceanográfica do Programa REVIZEE (Avaliação do Potencial Sustentável de Recursos Vivos da Zona Econômica Exclusiva), nos meses de setembro a dezembro de 2000. A área estudada está localizada entre 00°46'45"N a 13°53'45"S - 29°15'40"W a 39°49'42"W, onde foram realizados seis cruzeiros, totalizando 123 estações. As amostras foram coletadas em rede tipo bongo (malhas coletoras de 300 e 500 µm, com aros de 60 cm de diâmetro) acopladas com fluxômetro digital, em arrastos oblíquos na profundidade de 0 a 200 m. Foram considerados os organismos retidos na malha de 300 µm. A bordo, as amostras foram acondicionadas em recipientes plásticos, etiquetadas e fixadas em formaldeído a 4%, tamponado com tetraborato de sódio. Em laboratório, as amostras foram analisadas em placa do tipo "Bogorov", sob estereomicroscópio binocular. Foram examinados 5655 indivíduos da família Limacinidae, assim distribuídos: 03 gêneros e 05 espécies. Os representantes da família Limacinidae ocorreram em altas temperaturas e salinidades, caracterizando-se, assim, como tropicais e euhalinos.Heliconoides inflatus sobressaiu em abundância e frequência. Limacina lesueurii mostrou-se uma espécie rara e pouco frequente. Limacina trochiformis e L. bulimoides foram pouco abundantes e pouco frequentes.Limacina lesueurii e L. bulimoides foram registradas como primeira ocorrência em águas neríticas, sendo este o primeiro registro deL. lesueurii para as águas do Nordeste brasileiro.Limacina trochiformis e L. bulimoidestiveram ampla distribuição, apesar de pouco frequentes e pouco abundantes. A distribuição de Thielea helicoides restringiu-se às águas oceânicas. Foi observada uma correlação entre Limacina bulimoides, Heliconoides inflatus, Thielea helicoides eL. lesueurii por coexistirem no mesmo nicho.
ABSTRACT
An inventory of macroinvertebrates conducted in the Contas River basin in Northeastern Brazil found 13 species of freshwater mollusks. Most of the community was represented by pulmonate gastropods, including Physa acuta, Drepanotrema anatinum, D. cimex, D. lucidum, Biomphalaria straminea?, Gundlachia radiata?, G. ticaga and Hebetancylus moricandi; the prosobranchs Pomacea archimedis?, Melanoides tuberculata and Littoridina sp. were also found. Bivalves were less diversified, represented only by Pisidium pulchellum? and Eupera simoni?. The taxonomic composition and the small size of many species reflect the intermittent condition of the basin. Additionally, the occurrence of shells of five terrestrial species (Helicina angulata, Gastrocopta pellucida hordeacella?, Beckianum beckianum, Succinea sp. and Systrophiidae gen. et sp. indet.) in the rivers reflects the occasional heavy rainfalls and floods in the region. The invasive gastropod M. tuberculata was the most abundant and widely distributed species. All 13 species were found in the lower course, in the Atlantic Forest region, and most, but not all, were recorded in the upper course, in the Caatinga region. The distribution and the occurrence of the bivalve species exclusively in the Atlantic Forest region indicate that the locally higher annual precipitation provides favorable conditions for the survival of these mollusks, such as a more stable hydroperiod.
Treze espécies de moluscos de água doce foram encontradas em um inventário de macroinvertebrados realizado ao longo da bacia do Rio de Contas, no Nordeste do Brasil. A maioria da comunidade foi representada por gastrópodes pulmonados, como Physa acuta, Drepanotrema anatinum, D. cimex, D. lucidum, Biomphalaria straminea?, Gundlachia radiata?, G. ticaga e Hebetancylus moricandi, embora prosobrânquios, como Pomacea archimedis?, Melanoides tuberculata e Littoridina sp. também tenham sido encontrados. Bivalves foram menos diversificados, e foram representados por Pisidium pulchellum? e Eupera simoni?. A composição taxonômica e o pequeno tamanho alcançado por muitas espécies refletem a condição intermitente da bacia. Além disso, a ocorrência de conchas de cinco espécies terrestres (Helicina angulata, Gastrocopta pellucida hordeacella?, Beckianum beckianum, Succinea sp. e Systrophiidae gen. et sp. indet.) dentro dos rios reflete as fortes chuvas e inundações que ocorrem ocasionalmente na região. O gastrópode invasor M. tuberculata foi a espécie mais abundante e bem distribuída. Todas as espécies foram encontradas no curso inferior, na região da Mata Atlântica, e a maioria, mas não todas, foram registradas no curso superior, na região da Caatinga. Esta distribuição e a ocorrência das espécies de bivalves exclusivamente na região da Mata Atlântica indicam que a maior precipitação anual desta região fornece condições favoráveis para a sobrevivência destes moluscos, como um hidroperíodo mais estável.