Predicting the distribution of Omalonyx (Mollusca: Pulmonata: Succineidae) species from literature review, museum databases and new sampling efforts in Brazil / Predição da distribuição de Omalonyx (Mollusca: Pulmonata: Succineidae) a partir da revisão da literatura, dados de museu e novo esforço amostral no Brasil

Abstract Accurate distributional information is crucial for studies on systematics, biodiversity and conservation. To improve the knowledge regarding the geographical distribution of Omalonyx in South America, we present updated information based on data from a literature review, institutional collections and malacological surveys. All this information composed the dataset used to predict species distribution employing the Maximum Entropy Algorithm (MaxEnt). The model was run using data on species distribution, altitude and bioclimatic variables (WorldClim database). The model had consistent performance, and areas presenting similar conditions to areas where the species were recorded were considered areas of occurrence. The predicted occurrence areas included those that were already surveyed and those that are considered potential occurrence areas. The results demonstrate that the genus has widespread distribution in the Neotropical region and occurs in the tropical, temperate and arid regions of South America and Lesser Antilles. Omalonyx spp. were recorded in all South American countries and hydrographic regions. However, in some countries, there were only isolated records (ex: Colombia and Ecuador). Here, we also present the first record of Omalonyx spp. in four Brazilian States (Acre, Rondônia, Piaui, and Amapá). The genus was found in all hydrographic regions within Brazil and among 27 federative unities; it was absent from only two unities (Roraima State and Distrito Federal). This work contributes to the knowledge on Omalonyx spp. distribution and provides an important basis for the work of ecologists and taxonomists.

Resumo A informação precisa sobre a distribuição é crucial para os estudos sobre sistemática, biodiversidade e conservação. Para melhorar o conhecimento sobre a distribuição geográfica de Omalonyx na América do Sul, apresentamos informações atualizadas com base em dados de revisão de literatura, coleções institucionais e pesquisas malacológicas. Toda essa informação compôs o conjunto de dados usado para predição da distribuição de espécies empregando o Algoritmo de Entropia Máxima (MaxEnt). O modelo foi executado usando dados de distribuição de espécies, altitude e variáveis bioclimáticas (banco de dados WorldClim). O modelo apresentou um desempenho consistente e as áreas que apresentaram condições semelhantes às áreas onde as espécies foram registradas, foram consideradas áreas de ocorrência. As áreas de ocorrências previstas incluíram aquelas que já foram pesquisadas e aquelas que são consideradas áreas de ocorrência potencial. Os resultados demonstram que o gênero tem uma distribuição Neotropical ampla e que ocorre nas regiões tropical, temperada e árida da América do Sul e nas Pequenas Antilhas. Omalonyx spp. foram registradas em todos os países e bacias sul-americanas. No entanto, em alguns países, apenas registros isolados foram encontrados (ex: Colômbia e Equador). Aqui, também apresentamos o primeiro registro de Omalonyx spp. em quatro estados brasileiros (Acre, Rondônia, Piauí e Amapá). O gênero foi encontrado em todas as regiões hidrográficas no Brasil e nas 27 unidades federativas; sendo ausente em apenas duas unidades federativas (Estado de Roraima e Distrito Federal). Esse trabalho contribui para o conhecimento da distribuição das espécies de Omalonyx e fornece uma importante base para trabalhos de ecólogos e taxonomistas.

Freshwater gastropods of the Baixada Maranhense Microregion, an endemic area for schistosomiasis in the State of Maranhao, Brazil: I - qualitative study

Introduction: The Baixada Maranhense Microregion currently has the highest prevalence of schistosomiasis in the State of Maranhão, likely because this parasitosis is characterized as an occupational disease, and increased contact with water increases the risk of infection by Schistosoma mansoni. This paper reports the results of the first comprehensive freshwater malacological survey performed in the Baixada Maranhense Microregion. Methods: Freshwater mollusks were collected from the twenty-one municipalities of the Baixada Maranhense Microregion and from Bacurituba and Cajapió and were evaluated for infection by trematodes. Results: A total of 9,129 mollusks were collected (sixteen species), which included the first records of six species in the State of Maranhão: Gundlachia radiata, G. ticaga, Hebetancylus moricandi, Plesiophysa guadeloupensis, Pomacea bridgesii diffusa and Omalonyx sp. Biomphalaria glabrata was found in five municipalities, whereas B. straminea was found in nine. Biomphalaria glabrata and B. straminea were observed in syntopy in Pinheiro and São Bento. Of the 990 specimens of B. glabrata and the 2,109 specimens of B. straminea that were exposed to and/or analyzed for the presence of larval trematodes, only a single specimen of B. glabrata (0.1%) from São Bento shed S. mansoni. Other larval trematodes were first observed in mollusks from the State of Maranhão. Conclusions: These results indicate that the study area is epidemiologically important due to the presence of two natural vectors of schistosomiasis and the active transmission of schistosomiasis, which was confirmed in the infected specimen that was collected in this study. .

Reproduction of Omalonyx matheroni (Gastropoda: Succineidae) under laboratory conditions

The life histories of succineids have received relatively little attention. To evaluate life history characteristics of Omalonyx matheroni, we studied a Brazilian population (Reserva Particular do Patrimônio Natural Feliciano Miguel Abdala, in Caratinga, Minas Gerais, Brazil) under laboratory conditions. The aims of the present study were (1) to describe in detail an appropriate rearing method; (2) to investigate the effects of different temperature and photoperiod conditions; and (3) to assess the effects of self and cross-fertilization on the reproductive biology of these mollusks. We studied the oviposition site, the time to sexual maturity and the influences of photoperiod and temperature on reproductive parameters of O. matheroni reared under laboratory conditions. We tested three combinations of temperature and photoperiod, designated A, B and C (A: 25ºC, 24 hours of light; B: environmental conditions of temperature and photoperiod, characterized as follows: average máximum temperature=27.1ºC, average minimum temperature=18.3ºC, average day length=12.06 hours; and C: 25ºC, zero hours of light) and two rearing densities (I: isolated and G: grouped) on reproductive parameters (number of eggs per egg mass, number of unviable eggs per mass, egg mass incubation period, and duration of the hatching period). A total of 186 individuals and 565 egg masses were studied. Data were analyzed by Student’s t-test, two-way ANOVA and Chi-Square test. Eight generations were produced (March/2004-March/2006), from 35 field specimens, 91% of 3 197 eggs hatched. The time to sexual maturity was approximately three months for individuals reared in groups or in isolation (Student’s t-test: t=1.41, df=31, p=0.16); however, they differed significantly in weight (Student’s t-test: t=3.6, df=31, p<0.001). Regarding the influences of temperatura and photoperiod on reproductive parameters, under natural environmental conditions, individuals produced a greater number of eggs per mass (ANOVA: F2,573=84.15, p<0.001), with a longer incubation period (ANOVA: F2;559=170.05, p<0.001). The extreme photoperiod conditions of 24 hours of light or zero hours of light likely imposed stress and could be related to the significant reductions in the number of eggs per mass, and egg incubation period as well as the increased synchrony in egg hatching. No correlations were observed between the number of unviable eggs per mass and the temperature, photoperiod (ANOVA: F2,573=0.87, p=0.92) or rearing density (ANOVA: F1,573=0.21, p=0.64). Individuals reared in isolation under natural conditions produced more eggs per mass and did not presented any disadvantage with respect to the variables analyzed as compared to the animals reared in groups. These results indicate that O. matheroni can successfully reproduce by selfing. Rev. Biol. Trop. 60 (2): 553-566. Epub 2012 June 01.

Laminosioptes cysticola in free-range chickens in Minas Gerais, Brazil / Laminosioptes cysticola em galinhas de fundo de quintal em Minas Gerais, Brasil

The subcutaneous acarid parasite Laminosioptes cysticola, the fowl cyst mite, has been found for a number of years in free-range chickens of peri-urban and rural Minas Gerais, forming collagen cysts which may be subsequently calcified after the parasite's death. The role of free-range chickens as hosts and the possible risk of food-borne human allergy, as a result of its consumption in feed, are considered.

O parasito acarino subcutâneo Laminosioptes cysticola tem sido encontrado em galinhas de subsistência periurbanas e rurais em Minas Gerais, formando cistos arredondados que podem calcificar sob a pele após a morte do parasito. Detalhes do parasitismo e do parasito são discutidos, sendo especulado o risco potencial humano em alergia de origem alimentar pelo consumo da carne da ave contendo os cistos.

Angiostrongylus costaricensis (Nematoda: Protostrongylidae): estudo da via migratória em Omalonyx matheroni (Gastropoda: Succineidae) e análise comparativa da resposta hemocitária e desenvolvimento larvar em moluscos pulmonados / Angiostrongylus costaricensis (Nematoda: Protostrongylidae): study of the migratory way in Omalonyx matheroni (Gastropoda: Succineidae) and comparative analysis of the hemocytic reply and development to larvar in pulmonates snails

O nematódeo Angiostrongylus costaricensis tem como hospedeiros intermediários diversos moluscos pulmonados, no entanto, sua via-migratória foi estudada somente em Sarasinula marginata. Neste trabalho investigou-se 1- a via-migratória do parasita em Omalonyx matheroni, 2 - a reação tecidual e desenvolvimento larvar em alguns pulmonados (O. matheroni, Biomphalaria glabrata, Deroceras sp. e S. marginata), e 3 - o potencial como hospedeiro intermediário de O. matheroni e Deroceras sp. Espécimes de O. matheroni foram infectados com 1200 larvas L1 para preparação de cortes histológicos corados em HE. Para a via-migratória foram estudados pontos com 30 minutos, 1, 2, 4, 6 e 8 horas, 2, 5, 10, 12, 15, 20, 21, 25, 28 e 30 dias de infecção. A análise dos cortes histológicos revelou a ocorrência de infecção oral e cutânea. A via-migratória mostrou-se intimamente relacionada às vias do sistema circulatório indicando que as larvas são por estas conduzidas aos diversos órgãos. No estudo comparativo da reação hemocitária nos pulmonados esta diferiu em intensidade e grau de ativação celular. Todas as espécies se tornaram mais responsivas a L2 e à face côncava larvar (ventral). Deroceras sp. e O. matheroni apresentaram uma camada colágena ao redor dos granulomas, ausente em S. marginata e B. glabrata. A análise comparativa da resposta hemocitária em gastrópodes pulmonados demonstrou que os aspectos da infecção são muito semelhantes entre as espécies estudadas. No entanto, muitos padrões se mostraram variáveis (intensidade da resposta, ativação celular - morfologia - e presença de colágeno), demonstrando o alto grau de conservação do sistema imunológico inato e a heterogeneidade funcional dos hemócitos. No estudo do desenvolvimento larvar 10 exemplares de cada espécie foram infectados (400L1) e digeridos após 5, 10, 15, 20 e 30 dias. A porcentagem de cada estágio larvar recuperado com 15, 20 e 30 dias, apresentou diferenças significativas (qui-quadrado) entre as espécies...

Polymerase chain reaction and restriction fragment length polymorphism of cytocrome oxidase subunit I used for differentiation of Brazilian Biomphalaria species intermediate host of Schistosoma mansoni

The intermediate hosts of Schistosoma mansoni, in Brazil, Biomphalaria glabrata, B. tenagophila and B. straminea, were identified by restriction fragment length polymorphism analysis of the mitochondrial gene cytochrome oxidase I (COI). We performed digestions with two enzymes (AluI and RsaI), previously selected, based on sequences available in Genbank. The profiles obtained with RsaI showed to be the most informative once they were polymorphic patterns, corroborating with much morphological data. In addition, we performed COI digestion of B. straminea snails from Uruguay and Argentina