Assessing the role of taxonomic impediment in the knowledge on geographic distribution of Physidae (Gastropoda: Hygrophila) in South America, using an intensive-data approach.

There is a marked disparity in the state of knowledge of Holartic x Neotropical species of the freshwater snail family Physidae; the incipiency of data on Neotropical physids reflecting the lower number of dedicated specialists. The gaps in the knowledge on Neotropical physids have led to historical uncertainty about species validity. Revisiting the species is essential to reduce taxonomic impediment and delineating their probable distribution is the first step to attain this purpose. We aimed at critically analyze occurrence records of South American physids, compiled through an intensive search in the literature, biodiversity and molecular databases. We present a provisional characterization of the distribution of this family in South America, considering the probable versus the poorly documented distribution of the species. The critical underrepresentation of South American physids in collections, molecular databases and literature reinforces the role of taxonomic impediment in delaying the advance of the knowledge on species diversity. Malacological collections represented the main source of records, evidencing the relevance of unpublished data associated to specimens to assess distributional information on neglected groups. As most of the species are represented by shells, the reassessment of species identity and distribution must be done, using molecular and anatomical criteria for species delimitation.

Species catalogue of Drymaeus (Mesembrinus) Alberts, 1850 (Gastropoda: Bulimulidae) from Brazil and new data on morphology and distribution of Drymaeus (Mesembrinus) interpunctus (Martens, 1887).

Background: Herein, we attempted to obtain detailed data on the distribution of the species of Drymaeus (Mesembrinus) in Brazil, using biodiversity databases, malacological collections and literature as sources of occurrence records. We provided a catalogue of species, along with distribution maps. We also estimated the suitable distribution of Drymaeus (Mesembrinus) interpunctus using the maximum entropy approach. A detailed description of the anatomy of the soft parts of this species was provided, with new data on the pallial system. Materials and Methods: For each species we provided information on the compiled data associated with museum collections and the literature. Distribution maps including geographic boundaries, Brazilian biomes and altitude were made with QGIS software 3.16.10 Hannover. For niche modelling, nineteen bioclimatic variables and a topographic variable were used as predictors. The models were performed with MaxEnt version 3.3.3k. Results: Most of the species are represented by scarce material in malacological collections; for some species, these records correspond to type material, indicating that they have not been recollected. Most of the species were represented by shells making anatomical comparison and DNA analysis difficult, limiting our ability to provide new criteria for species delimitation. Our results allowed us to expand the known distribution area for three species, Drymaeus dutaillyi, D. gereti and D. oreades, with new occurrence records in Brazil. The MaxEnt model showed a thin area of high suitability to D. (M.) interpunctus in the Southeastern Brazil, corresponding to the Atlantic Forest. Minimum temperature of the coldest month and mean temperature of coldest quarter were the variables that most influenced the development of the model. Discussion: Drymaeus interpunctus was described based on specimens collected in Brazil without mention to the exact localities. Herein the new records from databases allowed to expand the known geographic distribution for this species and to infer its potential distribution. Although the type locality of D. interpunctus is in Brazil, the anatomy of the soft parts of specimens from this country was not previously described. The anatomy of the reproductive system of the specimens analyzed herein mostly corresponds to a previous description for specimens from Paraguay, except for the absence of penial sheath and the relative length of the bursa copulatrix duct. The results of niche modeling showed a thin area of high suitability for D. interpunctus and a vast area of moderate suitability, indicating that this species present a niche breadth that favors its occurrence in a range of different biomes, including less suitable areas. Conclusion: The small number of records obtained for most of the species and their restricted ranges associated with habitat destruction may indicate that they are of conservation concern.

Redescription and geographical distribution of Leiostracusobliquus (Reeve, 1849) (Mollusca, Gastropoda, Simpulopsidae).

Leiostracus Albers, 1850 was established to allocate land snails from Central America and Northern South America. Currently, approximately 19 species are considered valid. However, for most of them, the internal morphology is unknown. Leiostracusobliquus was described as a species of Bulimus from the state of Bahia based on shell characters. Until now, knowledge of this species has been scarce. The discovery of ethanol-preserved specimens from MZSP of this species allowed us to characterize, for the first time, the internal anatomy of this species and update its distribution. The shell of L.obliquus has seven to eight whorls and a wide pale-pink disrupted band all over the teleoconch. The rachidian tooth is small rectangular, symmetric, with round edges, and without differentiated cusps. After comparing the anatomy and radular characters between the shells of L.obliquus and L.carnavalescus, we found remarkable similarities in the morphology and color pattern.

Responses of Leptinaria unilamellata (Gastropoda: Subulinidae) to Novel Micro-Environmental Conditions: Shift in Shell Morphology and the Balance between Protection against Desiccation and Reproductive Success.

In the present study, we observed that Leptinaria unilamellata responds to changes in microclimatic conditions through shifts in shell morphology. Over three laboratory generations, shell differences between two populations, representing distinct morphotypes, became less evident. Only F1 generations from both populations showed shell morphometry very similar to the field parental snails, suggesting maternal effect. Snails from the locality with higher values of rainfall, relative humidity and evaporation index and smaller values of temperature and insolation produced more and larger hatchlings. Snails from the locality with less favorable climatic conditions presented shells traits that offer protection against desiccation, but reduce reproductive success. These snails showed smaller offspring production and faster response to a desiccation regime, through changes in conchiometrics. In addition, the results of the present study suggest that the spire index plays a less important role in determining protective properties of the shell of L. unilamellata, in response to desiccation risk, compared to aperture dimension. As shell aperture dimension is an important trait related to resistance to desiccation, and at the same time to reproduction, plastic responses to environmental conditions promoting the balance between survival and reproductive success are critical for the species adaptive success.

New Morphological Characterization of Latipes erinaceus (Gastropoda, Veronicellidae), Differential Diagnosis for the Genera Angustipes and Latipes, and Novel Combinations for Species of Latipes.

The genera Angustipes Colosi, 1922 and Latipes Colosi, 1922 were originally proposed as "groups" within the genus Vaginulus Ferrussac, 1822, and since their establishment they have been variously considered valid or invalid until they gained the ultimate status of genus. The descriptions of both genera are general and broadly inclusive, and this fact has complicated taxonomic recognition. Additionally, incomplete descriptions and difficult identification of characteristics in the name-bearing type specimens demonstrate the need to revisit the species and revise the two genera. Herein, we broaden the description of Latipes erinaceus Colosi, 1922 with respect to the circulatory system, the radula, the jaw, the position of entry of the ligation duct in the bursa copulatrix in relation to the canal of the bursa, the origin of the muscle of the penial gland, along with the morphometric characteristics of the phallus, the penial gland, the pedal gland, and the bursa copulatrix. We also propose new differential diagnoses for the genera Angustipes and Latipes, limited to the essential characteristics that enable taxonomic recognition. Hence, we propose the assignment of the species L. erinaceus, Latipes rosilus (Thiele, 1927), Latipes ribeirensis (Thiele, 1927), and Latipes absumptus (Colosi, 1921) to the genus Angustipes, based on the presence of morphological characteristics attributable to this genus, such as the phallus being short and conical; the bursa copulatrix being sessile or short, and lacking a head; the ligation duct inserted near the canal of the bursa; as well as on the similarity in phallus morphology with Angustipes difficilis Colosi, 1922, the type species of this genus.

Diversity and Distribution of Peritrich Ciliates on the Snail Physa acuta Draparnaud, 1805 (Gastropoda: Physidae) in a Eutrophic Lotic System.

Bianca Sartini, Roberto Marchesini, Sthefane D ´ávila, Marta D'Agosto, and Roberto Júnio Pedroso Dias (2018) Freshwater gastropods represent good models for the investigation of epibiotic relationships because their shells act as hard substrates, offering a range of microhabitats that peritrich ciliates can occupy. In the present study we analyzed the community composition and structure of peritrich epibionts on the basibiont freshwater gastropod Physa acuta. We also investigated the spatial distribution of these ciliates on the shells of the basibionts, assuming the premise that the shell is a topologically complex substrate. Among the 140 analyzed snails, 60.7% were colonized by peritrichs. We observed seven peritrich species: Epistylis plicatilis and Epistylis sp. (Epistylididae); Opercularia articulata (Operculariidae); Carchesium polypinum, Vorticella campanula and Vorticella sp. (Vorticellidae) and Thuricola kellicottiana (Vaginicollidae). We observed a high prevalence of epibiosis (> 60%) when all species of ciliates were considered conjunctly. However, the prevalence was low (1-58%) when each species was considered separately, reflecting their aggregate distribution pattern. The most prevalent species were Epistylis sp. (58.60%), Vorticella sp. (14.30%) and O. articulata (13.60%). Although the epibionts were distributed through the shell's entire extension, we observed greater values of abundance, density, diversity and dominance on the dorsal surface. Only Epistylis sp. was widely distributed on the ventral surface. We also observed that the peritrichs predominantly occupied the areas of the shell delimited by the sutures. We interpreted these distribution patterns considering that the peritrichs select their attachment sites under pressures related to basibiont behavior, physical forces that may dislocate them and protective characteristics of the shell's areas.

Ontogeny and morphological variability of shell in populations of Leptinaria unilamellata (d'Orbigny, 1835) (Mollusca, Pulmonata, Subulinidae).

BACKGROUND: Recent studies concerning species of land snails have revealed that the shell morphometrics can provide evidence of the differentiation among populations. In many cases, the morphologic analysis combined with the investigation of molecular variability, can support changes in taxonomy of studied groups. In this sense, the study of shell morphometry during snail development can contribute to the understanding of the structural mechanisms that creates the diversity observed. DESCRIPTION: The morphological and ontogenetic pattern differences were collected among snails from four different populations, kept under the same laboratorial conditions. It was possible to distinguish characteristic shell morphometrics for snails from each population. The snails from Barra Mansa and Floriano, locations with smaller precipitation indexes presented smaller shell aperture values. The results are discussed in terms of the role of the reproductive strategy of this species as a factor determining shell shape. CONCLUSIONS: Differences in growth allometry indicated that the whole shell forming process is different among the populations, not only the final form of the adult's shell. Some allometry relationships indicated that, during the snails' development, the increase in shell width is not proportional to the increase of the width and height of the shell aperture. Thus, there is possibly an antagonism between the adoption of K-strategy and protection against desiccation. Since the spire indices of L. unilamellata morphotypes cannot be explained by physical functional aspects, the most likely explanation is the reproductive strategy of this species.

Spatial distribution of Lymnaeidae (Mollusca, Basommatophora), intermediate host of Fasciola hepatica Linnaeus, 1758 (Trematoda, Digenea) in Brazil.

Snails of the family Lymnaeidae act as intermediate hosts in the biological cycle of Fasciola hepatica, which is a biological agent of fasciolosis, a parasitic disease of medical importance for humans and animals. The present work aimed to update and map the spatial distribution of the intermediate host snails of F. hepatica in Brazil. Data on the distribution of lymnaeids species were compiled from the Collection of Medical Malacology (Fiocruz-CMM, CPqRR), Collection of Malacology (MZUSP), "SpeciesLink" (CRIA) network and through systematic surveys in the literature. Our maps of the distribution of lymnaeids show that Pseudosuccinea columella is the most common species and it is widespread in the South and Southeast with few records in the Midwest, North and Northeast regions. The distribution of the Galba viatrix, G. cubensis and G. truncatula showed a few records in the South and Southeast regions, they were not reported for the Midwest, North and Northeast. In addition, in the South region there are a few records for G. viatrix and one occurrence of Lymnaea rupestris. Our findings resulted in the first map of the spatial distribution of Lymnaeidae species in Brazil which might be useful to better understand the fasciolosis distribution and delineate priority areas for control interventions.

SPATIAL DISTRIBUTION OF LYMNAEIDAE (MOLLUSCA, BASOMMATOPHORA), INTERMEDIATE HOST OF Fasciola hepatica LINNAEUS, 1758 (TREMATODA, DIGENEA) IN BRAZIL / Distribuição espacial de Lymnaeidae (Mollusca, Basommatophora), hospedeiros intermediários de Fasciola hepatica Linnaeus, 1758 (Trematoda, Digenea) no Brasil

Snails of the family Lymnaeidae act as intermediate hosts in the biological cycle of Fasciola hepatica, which is a biological agent of fasciolosis, a parasitic disease of medical importance for humans and animals. The present work aimed to update and map the spatial distribution of the intermediate host snails of F. hepatica in Brazil. Data on the distribution of lymnaeids species were compiled from the Collection of Medical Malacology (Fiocruz-CMM, CPqRR), Collection of Malacology (MZUSP), “SpeciesLink” (CRIA) network and through systematic surveys in the literature. Our maps of the distribution of lymnaeids show that Pseudosuccinea columella is the most common species and it is widespread in the South and Southeast with few records in the Midwest, North and Northeast regions. The distribution of the Galba viatrix, G. cubensis and G. truncatula showed a few records in the South and Southeast regions, they were not reported for the Midwest, North and Northeast. In addition, in the South region there are a few records for G. viatrix and one occurrence of Lymnaea rupestris. Our findings resulted in the first map of the spatial distribution of Lymnaeidae species in Brazil which might be useful to better understand the fasciolosis distribution and delineate priority areas for control interventions.

Moluscos da família Lymnaeidae são hospedeiros intermediários no ciclo biológico de Fasciola hepatica, agente etiológico da fasciolose, doença parasitária de importância médica para humanos e animais. O presente trabalho teve como objetivo datar e mapear a distribuição espacial dos hospedeiros intermediários de F. hepatica no Brasil. Os dados de distribuição das espécies de limneídeos foram obtidos das Coleções de Malacologia Medica (Fiocruz-CMM, CPqRR) e de Malacologia do Museu de Zoologia da Universidade de São Paulo (MZUSP), rede “SpeciesLink” (CRIA) e através de pesquisas sistemáticas na literatura. Os mapas de distribuição dos limneideos mostram que Pseudosuccinea columella é a espécie mais comum e distribuída nas regiões Sul e Sudeste com poucos registros nas regiões Centro-Oeste, Norte e Nordeste. Além disso, na região Sul os registros para G. viatrix são escassos e existe apenas um único relato de ocorrência para L. rupestris. Os dados obtidos resultaram no primeiro mapa de distribuição espacial das espécies de Lymnaeidae no Brasil, informação básica e relevante para estruturação de políticas de controle da fasciolose humana e animal.

Seroprevalence and risk factors of toxoplasmosis in cattle from extensive and semi-intensive rearing systems at Zona da Mata, Minas Gerais state, Southern Brazil.

BACKGROUND: Concerning the infection of humans by T. gondii, limited efforts have been directed to the elucidation of the role of horizontal transmission between hosts. One of the main routes of transmission from animals to humans occurs through the ingestion of raw or insufficiently cooked meat. However, even though the detection of T. gondii in meat constitutes an important short-term measure, control strategies can only be accomplished by a deeper understanding of the epidemiology of toxoplasmosis. The present study aimed to investigate the seroprevalence of toxoplasmosis in cattle from Zona da Mata, Minas Gerais, Brazil, and to identify associated risk factors, through an epidemiological investigation. METHODS: The animals studied (Bos indicus, breed Nelore or Gir) were reared in the Zona da Mata micro-region and killed at a commercial slaughterhouse at Juiz de Fora, Minas Gerais state. The animals came from 53 cattle farms with extensive (predominantly pasture feeding management) or semi-intensive (food management based on grazing, salt mineral and feed supplementation) rearing systems. Blood samples were collected from 1200 animals, and assigned to Indirect Fluorescent Antibody Test. RESULTS: When analyzing IgG anti-T.gondii we found an overall seroprevalence of 2.68%. In Brazil prevalences vary from 1.03% to 60%. Although in the present study, the seroprevalence per animal is considered low compared to those observed in other studies, we found out that of the 53 farms analyzed, 17 (34.69%) had one or more positive cattle. It is a considerable percentage, suggesting that the infection is well distributed through the Zona da Mata region. The results of the epidemiological investigation showed that the main risk factors of Toxoplasma gondii infection are related to animal management and to the definive host. There was a relationship between the number of seropositive cattle and the presence and number of resident cats, presence and number of stray cats, presence of cats walking freely, rat control by using cats and feed storage. CONCLUSION: These results may contribute to the development of preventive strategies in Brazil and other developing countries were extensive and semi-intensive cattle rearing systems are very widespread and the efforts to control this important zoonotic disease have attained little success.

Raman spectroscopy as a tool for polyunsaturated compound characterization in gastropod and limnic terrestrial shell specimens.

The colours of mollusc shells were determined using the Raman spectroscopy and these analyses suggest that the conjugated polyenes (carotenoids) and psittacofulvins are the organic pigments incorporated into their skeletal structures responsible by their colorations. The symmetric stretching vibration of the carbonate ion gives rise to a very strong Raman band at ca. 1089 cm(-1) and a weak band at 705 cm(-1), for all samples; the second band characterizes the aragonite as the inorganic matrix and can be used as a marker. The specimens show bands at 1523-1500 and at 1130-1119 cm(-1), assigned to the ν1 and ν2 modes of the polyenic chain vibrations, respectively. Another band at 1293 cm(-1), assigned to the CH=CH in-plane rocking mode of the olefinic hydrogen is also observed in all samples, which reinforces the psittacofulvin compound as the main pigment present in the analyzed samples.

The influence of caffeine and thymol on the survival, growth and reproduction of Subulina octona (Brugüière, 1789) (Mollusca, Subulinidae)

Subulina octona is a terrestrial snail which serves as an intermediate host for the parasites. It is also an agricultural pest. The aim of this work was to assess, during 120 days, the effects of caffeine and thymol at 2.5 g/L and 5 g/L on the hatchability, survival after hatching, growth and reproduction of S. octona under the laboratory conditions. A total of 240 eggs, 240 juveniles aged 10-day-old, and 240 aged 30-day-old were tested. The results showed that thymol (at 2.5 g/L and 5 g/L) and caffeine (at 5 g/L) acted as ovicides. In the 10-day-old juveniles, caffeine at 5 g/L caused 25 percent mortality and at 2.5 g/L it caused 30 percent mortality. Thymol at 2.5 and 5 g/L caused 20 and 22.5 percent mortality, respectively. In the 30-day-old juveniles, caffeine at 5 g/L caused 47.5 percent mortality.

Subulina octona é um molusco terrestre que atua como hospedeiro intermediário de parasitos. Também atua como praga agrícola. O objetivo deste trabalho foi avaliar, durante 120 dias, o efeito da cafeína e do timol a 2,5g/L e a 5g/L, sobre a eclodibilidade, a sobrevivência após a eclosão, crescimento e a reprodução de S. octona em condições de laboratório. Foram testados 240 ovos, 240 jovens com 10 e 30 dias de vida. Os resultados dos testes mostraram que o timol (5g/L e 2,5g/L) e a cafeína a 5g/L atuaram como ovicida. Nos jovens com 10 dias de vida a cafeína à 5g/L provocou uma mortalidade de 25 por cento e a 2,5 g/L 30 por cento. O timol a 2,5g/L e 5g/L provocou 20 e 22,5 por cento de mortalidade, respectivamente. Nos jovens com 30 dias de vida a cafeína a 5g/L causou 47,5 por cento de mortalidade. Esses resultados sugerem novos estudos no campo.

Influence of substrate humidity on desiccation resistance capacity in Subulina octona (Mollusca, Subulinidae)

The aim of this study was to verify the influence of substrate humidity on desiccation resistance of Subulina octona, continuously exposed, for 48 h, to the temperature of 35 °C. Forty individuals conditioned in 2 plastic boxes, one box containing black earth humidified with 40 ml water and the other one containing dry black earth were used. The retraction of cephalopodal mass inside the shell and the number of dead individuals was evaluated. Snails from dry and humid substrate boxes showed cephalopodal mass retraction of 9.9 cm±2.88 and 2.78 cm±3.17, respectively, after 12 h of exposure; 8.55 cm±1.3 and 6.33 cm±2.91, after 24 h; 11.07 cm±4.19 and 7.27 cm±2.7, after 36 h, 9.12 cm±2.15 and 6.47 cm±2.11, after 48 h. Every individual of dry substrate box died whereas every individual of humid substrate box survived. These results showed that substrate humidity was an influent factor regarding desiccation resistance in S. octona.

O objetivo deste trabalho foi verificar a influência da umidade do substrato sobre a resistência à dessecação em indivíduos da espécie S. octona, submetidos a uma exposição contínua, por 48 horas, à temperatura de 35 °C. Foram utilizados 40 indivíduos, acondicionados em dois potes plásticos, um pote contendo terra vegetal® umedecida com 40ml de água e outro contendo terra vegetal seca, mantidos em câmara climatizada a 35±1 °C. Foram verificados, a retração da massa cefalopodal no interior da concha e o número de indivíduos mortos. Os moluscos do pote com substrato seco e do pote com substrato úmido apresentaram retração da massa cefalopodal de 9,9cm±2,88 e 2,78cm±3,17 respectivamente, após 12 horas de exposição; 8,55cm±1,3 e 6,33cm±2,91, após 24 horas; 11,7cm±4,19 e 7,27cm±2,7, após 36 horas e 9,12cm±2,15 e 6,47cm±2,11, após 48 horas. Todos os indivíduos do pote com substrato seco morreram, enquanto todos os indivíduos do pote com substrato úmido sobreviveram. Esses resultados demonstram que a umidade do substrato é um fator que influencia a resistência à dessecação em S. octona.

First record of epibionts peritrichids and suctorians (Protozoa, Ciliophora) on Pomacea lineata (Spix, 1827)

This study made a survey on the ciliate protozoans from Peritrichid and Suctorian taxa, epibionts of Pomacea lineata (Spix, 1827) (Ampullariidae). Fifty mollusks were collected in places of irrigation ditches and shell was scraped with a scalpel and the extracted material was analyzed in vivo by light microscopy. All examined mollusks presented epibiont ciliates on their shells. For the first time epibiont ciliates in P. lineata was record. Seven genera of ciliates: five peritrichids and two suctorians, were identified and classified within the subclass Peritrichia: Carchesium Ehrenberg, 1838 (Vorticellidae), Epistylis Ehrenberg, 1830 (Epistylidae), Opercularia Stein, 1854 (Operculariidae), Vaginicola Lamarck, 1816 (Vaginicolidae) and Vorticella Linnaeus, 1767 (Vorticellidae); and Suctoria: Acineta Ehrenberg,1834 (Acinetidae) and Tokophrya Bütschli,1889 (Tokophrydae). The results showed that P. lineata constitute the microenvironment of a ciliate protozoan community that presents complex trophic interactions.

O objetivo do presente estudo foi realizar um levantamento dos protozoários ciliados dos táxons Peritrichia e Suctoria, epibiontes de Pomacea lineata (Spix, 1827) (Ampullariidae). Cinqüenta moluscos foram coletados em ambientes de vala de irrigação, em Juiz de Fora, Minas Gerais. As conchas dos moluscos foram raspadas com bisturi e o material extraído analisado in vivo sob o microscópio de luz. Todos os moluscos examinados apresentaram ciliados epibiontes em suas conchas. Registra-se pela primeira vez ciliados epibiontes em P. lineata. Sete gêneros de ciliados: cinco peritríquios e dois suctórios foram identificados e classificados nas subclasses Peritrichia : Carchesium Ehrenberg, 1838 (Vorticellidae), Epistylis Ehrenberg, 1830 (Epistylidae), Opercularia Stein, 1854 (Operculariidae), Vaginicola Lamarck, 1816 (Vaginicolidae) e Vorticella Lìnnaeus, 1767 (Vorticellidae); e Suctoria: Acineta Ehrenberg, 1834 (Acinetidae) e Tokophrya Bütschli, 1889 (Tokophrydae). Os resultados deste estudo demonstraram que P. lineata constitui o microambiente de uma comunidade de protozoários ciliados que exibem interações tróficas complexas.

Ritmo de atividade de Bradybaena similaris (Férussac, 1821) (Mollusca, Xanthonychidae) de acordo com a idade / The relationship between activity rhythm and age in Bradybaena similaris (Ferussac, 1821) (Mollusca, Xanthonychidae)

O presente trabalho descreve e quantifica as categorias comportamentais de três grupos etários de Bradybaena similaris, de 22 animais cada: Grupo 1, 80 dias de idade, Grupo 2, 40 dias de idade e Grupo 3, recém eclodidos. Foram descritas oito categorias comportamentais. A atividade foi major no período noturno (8,0

, 1,9

, 4,3

) do que no diurno (6,1

, 1,7

, 2,7

This study describes and quantifies the behavioral categories of three age groups of Bradybaena similaris, with 22 animals each (Group 1, 80 days, Group 2, 40 days and Group 3, newly hatched). Eight categories were described. Activity was higher during the night (8,0

, 1,9

, 4,3

) than during the day (6,1

, 1,7

), para os três grupos. O pico de atividade ocorreu no período noturno (Grupo 1: entre 23:00 e 01:00 e entre 03:00 e 6:00; Grupo 3: entre 21:00 e 22:00 e entre 06:00 e 07:00). O padrão de atividade diferiu significativamente de acordo com a faixa etária dos moluscos (p < 0,0001): indivíduos do Grupo 1 foram os mais ativos, seguidos pelos animais do Grupo 3, uma diferença possivelmente relacionada a fase reprodutiva da espécie(AU)

, 2,7C/), for the three study groups. Activity peaks occurred during the night (Group 1: from 23:00 to 01:00 and from 03:00 to 6:00; Group 3: from 21:00 to 22:00 and from 06:00 to 07:00). Activity patterns differed significantly according to age of mollusks (p < 0,0001). Individuals of Group 1 were most active, followed by animals of Group 3, a difference possibly related to the reproductive phase of the species(AU)