New record of the invasive snail Melanoides tuberculata (Gastropoda, Thiaridae) - Ceará State, Brazil / Novo registro do gastropode invasor Melanoides tuberculata (Gastropoda, Thiaridae) - Estado do Ceará, Brasil

Abstract Melanoides tuberculata is a freshwater gastropod native to Africa and Asia, and currently presents distributed worldwide. The first record of Melanoides tuberculata in South America occurred in Brazil, in the city of Santos, state of São Paulo, in 1967. Therefore, the objective of the present study is to report the occurrence of Melanoides tuberculata for Banana Lagoon and to characterize the current population situation. The gastropods were collected through direct visualization of shells, morphometric measurements of Melanoides tuberculata shells were determined using a digital caliper. After identifying the gastropod and its first distribution in the area, a preliminary descriptive analysis of the population was carried out. The gastropods were classified by grouping the individuals into four classes according to the shell width (mm). This is the first record of the occurrence of Melanoides tuberculata, in Banana Lagoon, Caucaia municipality, Ceará state, Northeast Brazil, being the largest specimen cited in the literature (33.77 mm) and 92.65% of the gastropods present in sizes above the first reproduction stages.

Resumo Melanoides tuberculata é um gastrópode de água doce nativo da África e da Ásia e atualmente apresenta-se distribuído mundialmente. O primeiro registro de Melanoides tuberculata na América do Sul ocorreu no Brasil, na cidade de Santos, estado de São Paulo, em 1967. Portanto, o objetivo do presente estudo é relatar a ocorrência de Melanoides tuberculata para Lagoa do Banana, caracterizando a situação atual da população no local. Os gastrópodes foram coletados através da visualização direta de conchas, e as medidas morfométricas das conchas de Melanoides tuberculata foram determinadas por meio de um paquímetro digital. Após identificar o gastrópode e constando sua primeira distribuição na área, realizou-se uma análise preliminar descritiva da população. Os gastrópodes foram classificados agrupando os indivíduos em quatro classes de acordo com a largura da concha (mm). Este é o primeiro registro da ocorrência de Melanoides tuberculata, na Lagoa da Banana, município de Caucaia, estado do Ceará, Nordeste do Brasil, sendo o maior exemplar citado na literatura (33,77 mm) já registrado e 92,65% dos gastrópodes apresentam-se em tamanhos acima do primeiro estágios de reprodução.

Evaluation of the feeding preference between the aquatic macrophytes Egeria densa and Chara indica by the invasive mollusk Melanoides tuberculata / Avaliação da preferência do molusco invasor Melanoides tuberculata pelas macrófitas aquáticas Egeria densa e Chara indica

Abstract This study evaluated the feeding preference of the invasive mollusk Melaniudes tuberculata between the aquatic macrophytes Egeria densa and Chara indica. The experiment consisted of twelve experimental units (glass aquariums) each of which contained three liters of water and three compartments. Fragments of E. densa and C. indica were placed in separate compartments within each unit; the third compartment, which did not contain macrophytes, was used as the control. Twenty Melanoides tuberculata individuals were placed in each unit and monitored hourly over the course of 24 hours for preferential movements. Physical and chemical water variables were measured at the beginning and end of the experiment. Habitat complexity was determined through collected macrophyte fragments and determined using the Fractop program. After 24 hours, the highest average number of individuals was observed in the treatment with Chara indica (ten individuals), which differed significantly from the treatment with E. densa (four individuals) and the control treatment (two individuals). The number of individuals between the E. densa and control treatment were similar. M. tuberculata showed a clear feeding preference for C. indica.

Resumo O presente trabalho teve como objetivo avaliar a preferência do molusco invasor M. tuberculata pelas macrófitas aquáticas Egeria densa e Chara indica. Doze unidades experimentais (aquários de vidro), com dimensões de 30×15×15 cm, subdivida em três compartimentos foram utilizadas. Em cada unidade experimental foram adicionados três litros de água, sendo que em dois compartimentos foram adicionados aleatoriamente fragmentos de E. densa e C. indica e um compartimento ficou sem planta (controle). Na parte central do aquário foram adicionados os moluscos equidistantes dos três compartimentos. O experimento teve duração de 24 horas, sendo vistoriado e contabilizado o número de organismos presentes em cada compartimento a cada hora. As variáveis ambientais foram medidas no inicio e fim do experimento. Fragmentos de macrófitas foram coletados para determinação da complexidade do habitat através do programa Fractop. Após 24 horas, os resultados mostraram um maior valor médio de indivíduos no tratamento que possuía Chara indica (dez indivíduos), que diferiu significativamente do tratamento com E. densa (quatro indivíduos) e do tratamento controle (dois indivíduos). Os tratamentos com E. densa e o controle foram semelhantes entre si evidenciando, uma possível preferência do molusco por a C. indica.

New record of the invasive snail Melanoides tuberculata (Gastropoda, Thiaridae) - Ceará State, Brazil

Abstract Melanoides tuberculata is a freshwater gastropod native to Africa and Asia, and currently presents distributed worldwide. The first record of Melanoides tuberculata in South America occurred in Brazil, in the city of Santos, state of São Paulo, in 1967. Therefore, the objective of the present study is to report the occurrence of Melanoides tuberculata for Banana Lagoon and to characterize the current population situation. The gastropods were collected through direct visualization of shells, morphometric measurements of Melanoides tuberculata shells were determined using a digital caliper. After identifying the gastropod and its first distribution in the area, a preliminary descriptive analysis of the population was carried out. The gastropods were classified by grouping the individuals into four classes according to the shell width (mm). This is the first record of the occurrence of Melanoides tuberculata, in Banana Lagoon, Caucaia municipality, Ceará state, Northeast Brazil, being the largest specimen cited in the literature (33.77 mm) and 92.65% of the gastropods present in sizes above the first reproduction stages.

Resumo Melanoides tuberculata é um gastrópode de água doce nativo da África e da Ásia e atualmente apresenta-se distribuído mundialmente. O primeiro registro de Melanoides tuberculata na América do Sul ocorreu no Brasil, na cidade de Santos, estado de São Paulo, em 1967. Portanto, o objetivo do presente estudo é relatar a ocorrência de Melanoides tuberculata para Lagoa do Banana, caracterizando a situação atual da população no local. Os gastrópodes foram coletados através da visualização direta de conchas, e as medidas morfométricas das conchas de Melanoides tuberculata foram determinadas por meio de um paquímetro digital. Após identificar o gastrópode e constando sua primeira distribuição na área, realizou-se uma análise preliminar descritiva da população. Os gastrópodes foram classificados agrupando os indivíduos em quatro classes de acordo com a largura da concha (mm). Este é o primeiro registro da ocorrência de Melanoides tuberculata, na Lagoa da Banana, município de Caucaia, estado do Ceará, Nordeste do Brasil, sendo o maior exemplar citado na literatura (33,77 mm) já registrado e 92,65% dos gastrópodes apresentam-se em tamanhos acima do primeiro estágios de reprodução.

Avaliação da atividade moluscicida de extratos vegetais sobre Achatina fulica Bowdich (Mollusca, Achatinidae) / Evaluation of the molluscicidal activity of vegetal extracts on Achatina fulica Bowdich (Achatinidae)

Achatina fulica Bowdich (Achatinidae) é um gastrópode terrestre pulmonado e tornou-se praga de pequenos cultivos de subsistência, sendo considerado uma ameaça à agricultura sustentável em alguns países, demandando altos custos em tentativas de controle, as quais, em sua maioria, resultaram em fracasso; ainda, pode atuar como hospedeiro intermediário de nematódeos. Nesse contexto, a procura por substâncias facilmente biodegradáveis tem aumentado o interesse pelo uso de moluscicidas de origem vegetal. Assim, o estudo teve como objetivo verificar a ação de extratos aquosos de folhas de Bacharis dracunculifolia DC., Morus rubra L., Cyperus rotundus L. e Euphorbia heterophylla L. e gemas florais de Sygygium aromaticum (L.) Merr. & Perry como possíveis moluscicidas. Destas, S. aromaticum e E. heterophylla foram ativas como moluscicidas, e C. rotundus não exibiu atividade moluscicida sobre esse gastrópode. Independentemente da espécie vegetal testada, nenhuma demonstrou atividade ovicida. Os resultados do presente estudo indicam que os extratos aquosos de folhas de E. heterophylla e de gemas florais de S. aromaticum podem se constituir em uma estratégia viável de controle alternativo de moluscos terrestres.(AU)

Achatina fulica Bowdich (Achatinidae) is a terrestrial pulmonary gastropod that has become a pest in small subsistence plantations. Also it is considered as a threat to sustainable agriculture in some countries, which demand high investments in order to control it; however, the most part of the tried methods have failed. This species can also act as an intermediate host of nematodes. In this context, the search for compounds easily biodegradable has increased the interest for using molluscicidal agents obtained from plant sources. Therefore, this study aimed to evaluate leaves extracts of Bacharis dracunculifolia DC., Morus rubra L., Cyperus rotundus L. and buds extracts of Euphorbia heterophylla L. and Sygygium aromaticum (L.) Merr. & Perry as possible molluscicidal agents. From these species, S. aromaticum and E. heterophylla were active as molluscicidal agents affecting survival rate of A. fulica and, C. rotundus did not show molluscicidal activity over this gastropod. None of the plant species tested showed ovicidal activity. The results of the present study indicate that the aqueous extracts of S. aromaticum buds and E. heterophylla leaves can be a viable approach for alternative control of terrestrial molluscs.(AU)

Two Cases of Neurotoxin Tetramine Poisoning Following Ingestion of Buccinum Striatissinum

Some carnivorous gastropods have heat stable tetramine toxins in their salivary glands. This toxin is an autonomic ganglionic blocking agent that enables them to catch the prey easily by paralyzing their targets. Acute tetramine toxin poisoning in humans from eating whelks has been well described based on numerous cases, but is rare in Korea. Symptoms of tetramine poisoning include eyeball pain, blurred vision, headache, dizziness, muscular twitching, tingling of hands and feet, weakness, paralysis and sometimes collapse. Gastrointestinal symptoms, such as abdominal pain, nausea, and vomiting can also occur. However, intoxication is self-limiting and patients will usually recover in about 24 hours. Herein, we report 2 cases of tetramine poisoning after ingestion of Buccinum striatissinum as meat and soup.

Two Cases of Neurotoxin Tetramine Poisoning Following Ingestion of Buccinum Striatissinum

Some carnivorous gastropods have heat stable tetramine toxins in their salivary glands. This toxin is an autonomic ganglionic blocking agent that enables them to catch the prey easily by paralyzing their targets. Acute tetramine toxin poisoning in humans from eating whelks has been well described based on numerous cases, but is rare in Korea. Symptoms of tetramine poisoning include eyeball pain, blurred vision, headache, dizziness, muscular twitching, tingling of hands and feet, weakness, paralysis and sometimes collapse. Gastrointestinal symptoms, such as abdominal pain, nausea, and vomiting can also occur. However, intoxication is self-limiting and patients will usually recover in about 24 hours. Herein, we report 2 cases of tetramine poisoning after ingestion of Buccinum striatissinum as meat and soup.

Shell occupation by the hermit crab Dardanus insignis (Decapoda, Diogenidae) from the north Coast of São Paulo state, Brazil

Abstract The pattern of shell occupation by the hermit crab Dardanus insignis (Saussure, 1858) from the subtropical region of southeastern coast of Brazil was investigated in the present study. The percentage of shell types that were occupied and the morphometric relationships between hermit crabs and occupied shells were analyzed from monthly collections conducted during two years (from January 1998 to December 1999). Individuals were categorized according to sex and gonadal maturation, weighed and measured with respect to their cephalothoracic shield length (CSL) and wet weight (CWW). Shells were measured regarding their aperture width (SAW), dry weight (SDW) and internal volume (SIV). A total of 1086 hermit crabs was collected, occupying shells of 11 gastropod species. Olivancillaria urceus (Roding, 1798) was most commonly used by the hermit crab D. insignis, followed by Buccinanops cochlidium (Dillwyn, 1817), and Stramonita haemastoma (Linnaeus, 1767). The highest determination coefficients (r2 > 0.50, p 0.01) were recorded particularly in the morphometric relationships between CSL vs. CWW and SAW vs. SIV, which are important indication that in this D. insignis population the great majority the animals occupied adequate shells during the two years analysed. The high number of used shell species and relative plasticity in pattern of shell utilization by smaller individuals of D. insignis indicated that occupation is influenced by the shell availability, while larger individuals demonstrated more specialized occupation in Tonna galea (Linnaeus, 1758) shell.

Resumo O padrão de ocupação de conchas pelo ermitão D. insignis (Saussure, 1858) na região subtropical da costa sudeste do Brasil, foi investigada no presente estudo. Foram analisadas a percentual de tipos de conchas que foram ocupados e as relações morfométricas entre os ermitões e conchas ocupadas, a partir de coletas mensais realizadas durante dois anos (de janeiro de 1998 a dezembro de 1999). Os indivíduos foram classificados de acordo com o sexo e maturação, pesados e medidos em relação ao comprimento escudo cefalotoracico (CEC) e peso úmido (CPU). As conchas foram medidas em relação à sua largura de abertura (LAC), peso seco (PSC) e volume interno (VIC). Um total de 1.086 ermitões foram coletados, ocupando conchas de 11 espécies de gastrópodos. Olivancillaria urceus (Roding, 1798) foi a mais utilizada pelo ermitão D. insignis, seguido por Buccinanops cochlidium (Dillwyn, 1817), e Stramonita haemastoma (Linnaeus, 1767). Os maiores coeficientes de determinação (r2 > 0,50, p 0,01) foram registrados principalmente nas relações morfométricas entre CEC e CPU contra LAC e VIC, que é uma importante indicação de que nesta população de D. insignis a grande maioria dos animais ocupavam conchas adequadas durante os dois anos analisados. O elevado número de espécies de conchas utilizadas e a relativa plasticidade no padrão de ocupação de conchas pelos menores indivíduos de D. insignis indicaram que a ocupação é influenciada pela disponibilidade de conchas, enquanto os indivíduos maiores demonstraram uma ocupação mais especializadas na concha de Tonna galea (Linnaeus, 1758).

Shell occupation by the hermit crab Dardanus insignis (Decapoda, Diogenidae) from the north Coast of São Paulo state, Brazil / Ocupação de conchas pelo ermitão Dardanus insignis na costa norte do estado de São Paulo, Brasil

Abstract The pattern of shell occupation by the hermit crab Dardanus insignis (Saussure, 1858) from the subtropical region of southeastern coast of Brazil was investigated in the present study. The percentage of shell types that were occupied and the morphometric relationships between hermit crabs and occupied shells were analyzed from monthly collections conducted during two years (from January 1998 to December 1999). Individuals were categorized according to sex and gonadal maturation, weighed and measured with respect to their cephalothoracic shield length (CSL) and wet weight (CWW). Shells were measured regarding their aperture width (SAW), dry weight (SDW) and internal volume (SIV). A total of 1086 hermit crabs was collected, occupying shells of 11 gastropod species. Olivancillaria urceus (Roding, 1798) was most commonly used by the hermit crab D. insignis, followed by Buccinanops cochlidium (Dillwyn, 1817), and Stramonita haemastoma (Linnaeus, 1767). The highest determination coefficients (r2 > 0.50, p < 0.01) were recorded particularly in the morphometric relationships between CSL vs. CWW and SAW vs. SIV, which are important indication that in this D. insignis population the great majority the animals occupied adequate shells during the two years analysed. The high number of used shell species and relative plasticity in pattern of shell utilization by smaller individuals of D. insignis indicated that occupation is influenced by the shell availability, while larger individuals demonstrated more specialized occupation in Tonna galea (Linnaeus, 1758) shell.

Resumo O padrão de ocupação de conchas pelo ermitão D. insignis (Saussure, 1858) na região subtropical da costa sudeste do Brasil, foi investigada no presente estudo. Foram analisadas a percentual de tipos de conchas que foram ocupados e as relações morfométricas entre os ermitões e conchas ocupadas, a partir de coletas mensais realizadas durante dois anos (de janeiro de 1998 a dezembro de 1999). Os indivíduos foram classificados de acordo com o sexo e maturação, pesados ​​e medidos em relação ao comprimento escudo cefalotoracico (CEC) e peso úmido (CPU). As conchas foram medidas em relação à sua largura de abertura (LAC), peso seco (PSC) e volume interno (VIC). Um total de 1.086 ermitões foram coletados, ocupando conchas de 11 espécies de gastrópodos. Olivancillaria urceus (Roding, 1798) foi a mais utilizada pelo ermitão D. insignis, seguido por Buccinanops cochlidium (Dillwyn, 1817), e Stramonita haemastoma (Linnaeus, 1767). Os maiores coeficientes de determinação (r2 > 0,50, p < 0,01) foram registrados principalmente nas relações morfométricas entre CEC e CPU contra LAC e VIC, que é uma importante indicação de que nesta população de D. insignis a grande maioria dos animais ocupavam conchas adequadas durante os dois anos analisados. O elevado número de espécies de conchas utilizadas ​​e a relativa plasticidade no padrão de ocupação de conchas pelos menores indivíduos de D. insignis indicaram que a ocupação é influenciada pela disponibilidade de conchas, enquanto os indivíduos maiores demonstraram uma ocupação mais especializadas na concha de Tonna galea (Linnaeus, 1758).

Composición, abundancia y distribución de las poblaciones de gasterópodos de importancia comercial en La Guajira, Caribe colombiano / Composition, abundance and distribution of populations of commercially important gastropods in La Guajira, Colombian Caribbean

In the continental Colombian Caribbean the conch resource exploitation and the status of snails populations has been poorly studied, which are reflected in the lack of fisheries management. This study assesses composition, population density and distribution of the gastropods species that make conch resource in La Guajira region. Underwater visual censuses for snails were performed between September-November 2009 in 145 100x4m (400m²) transects, spanning a total area of 56 920m² between Riohacha and Cabo de la Vela. The study was complemented with the evaluation of composition, abundance and size of gastropods conch found in the discarded-by-fishermen shell mounds in 13 beaches. In October 2010 another 40 transects were evaluated (16 000m²) from the Southern of Riohacha to the Camarones village (La Guajira). We found a total of 9 911 snails belonging to 12 species, the most abundant being Strombus pugilis with 8 912 individuals and an average density of 1 538.4±3 662.6 ind./ha , followed by Vasum muricatum with 374 individuals and an average density of 51.8±91.2 ind./ha. Calculating the importance value index (IVI) for both living organisms as the empty shells on beaches, shows that Turbinella angulata is the most used species by artisanal fishermen in the region. Cassis madagascariensis and Cassis tuberosa are also important snail resources in the region (as suggested by the number of empty shells found in beaches), but its densities were low. Strombus gigas, with only three living organisms found in the area, presented the lowest abundance ever found in the Colombian Caribbean (0.52±3.6 ind./ha), showing that queen conch population in La Guajira can- not support commercial exploitation. The abundance of discarded S. gigas shells on beaches suggests resource exploitation in the recent past. Results remarks the urgency of implementing management plans for snail fisheries in the region.

En el Caribe continental colombiano el aprovechamiento del recurso caracol y el estado de sus poblaciones han sido poco estudiados, esto se refleja en la carencia de un ordenamiento pesquero. Se evaluó la composición, densidad poblacional y distribución de las especies que conforman ese recurso en La Guajira. Se realizaron censos visuales entre septiembre y noviembre 2009 en 145 transectos de 100x4m (400m²), abarcando un área de 56 920m² entre Riohacha y el Cabo de la Vela. También se evaluó la composición, abundancia y talla de conchas de gasterópodos en depósitos de conchas vacías en 13 playas. En octubre 2010 se evaluaron 40 transectos más (16 000m²), desde el sur de Riohacha hasta Camarones. Se encontraron 9 911 caracoles de 12 especies, siendo Strombus pugilis el más abundante con 8 912 individuos y densidad de 1 538.4±3 662.6 ind./ha, seguido por Vasum muricatum con 374 individuos y densidad de 51.8±91.2 ind./ha. El índice de valor de importancia (IVI) de caracoles vivos y de conchas en las playas, muestran a Turbinella angulata como la especie más aprovechada por pescadores artesanales. Los resultados denotan la urgencia de realizar planes de manejo pesquero para este recurso en la región.

Effect of Cadmium on Oxygen Consumption in Fresh Water Gastropod–Bellamya (Viviparous) Bengalensis (Lamark).

The rate of oxygen consumption was measured in cadmium chloride treated gastropod –Bellamya (viviparous) bengalensis for 7days, 14days and 21days and compared to the levels of controlled gastropod –Bellamya (viviparous) bengalensis. The study shows that the average oxygen consumption rate was decreased in treated group as compared group.

Cercaria caribbea LVIII Cable, 1963 (Digenea: Cyathocotylidae) in the Republic of Korea and Its Surface Ultrastructure

Cercaria caribbea LVIII Cable, 1963 (Digenea: Cyathocotylidae) was detected from a brackish water gastropod species (Cerithideopsilla cingulata) in a coatal area of Shinan-gun, Jeollanam-do (Province), the Republic of Korea, and its surface ultrastructure was studied using a scanning electron microscope. The cercariae were found freely swimming or enveloped within daughter sporocysts when the snail host was mechanically broken. They were morphologically characterized by a linguiform and ventrally concave body, a long and bifurcated tail, and the presence of a holdfast (=tribocytic) organ posterior to the ventral sucker. On the whole ventral and dorsal surfaces, peg-like tegumental spines were densely distributed. Around the oral sucker, several sensory papillae, each with a short cilium, were distributed, and on the tail, sensory papillae, each with an extensively long cilium, were observed. This is the first record describing a cyathocotylid cercaria from a brackish water gastropod in the Republic of Korea.

Gasterópodos asociados al alga calcárea Halimeda opuntia (Udoteaceae) en Puerto Rico

Gastropods associated with the calcareous alga Halimeda opuntia (Udoteaceae) in Puerto Rico. Gastropod communities associated with the calcareous green alga Halimeda opuntia are described and compared for two Puerto Rico coral reefs: one in the northeast with front tradewinds (windward zone) and one in the southwest (leeward zone). We analyzed the content of 21 lots (2432 g) of H. opuntia from leeward zone and 15 lots (2448 g) from the windward zone. In total we recovered 526 gastropods (prosobranchs) classified in 54 taxa. Thirteen species of gastropods represented 79.6% of the community. Differences between species richness and mean density values were not significant (p>0.100). Forty species were identified from leeward and thirty one (31) species from windward. Gastropod mean density was 13.9 /100g of algae in leeward and 7.6/100g in windward. Significant differences were found for the Simpson Diversity Index (0.91 in the leeward and 0.82 in the windward community; t=3.44, α=0.005). We found no correlation between the weight of the algae and the frequency of the gastropods (R²=0.0893 in leeward, 0.0249 windward and 0.0923 for both). The relationship between species composition in lots of windward and leeward study sites was explored via polar ordination and no segregation was found. When compared, the gastropod communities found in H. opuntia collected in coral reefs in Puerto Rico were more similar within them than any other communities found in other genera of seaweed and in other environments. Our results agree with the hypothesis that H. opuntia offers the interstitial community a protected microhabitat from water movement impact. H. opuntia creates more homogenous conditions than those of the habitat where we found the algae. Rev. Biol. Trop. 56 (4): 1665-1675. Epub 2008 December 12.

Se describen y comparan las comunidades de gasterópodos asociados al alga verde calcárea H. opuntia. Se compararon estas comunidades en arrecifes coralinos de lugares geográfica y ambientalmente diferentes, uno en el noreste de Puerto Rico, frente a los vientos alisios (barlovento), el otro en el suroeste (sotavento). Se analizó el contenido de 15 lotes (2432 g) de H. opuntia recolectadas en la estación de sotavento y 21 lotes (2448 g) en la de barlovento. En los 36 lotes se recuperaron 526 gasterópodos (prosobranquios) que se clasificaron en 54 taxones. Trece especies de gasterópodos representaron el 79.6% de la muestra de la comunidad. No encontramos diferencias significativas en las densidades de gasterópodos ni en la riqueza de especies (p>0.100). La densidad promedio fue de 13.9/100 g alga en la estación de sotavento y 7.6/100 g en la de barlovento. Se identificaron 40 especies diferentes en las muestras de sotavento y 31 en las de barlovento. Solamente se encontraron diferencias significativas en los valores de diversidad (Simpson), de 0.91 para la comunidad de sotavento y de 0.82 en la de barlovento (t = 3.44, α = 0.05). No encontramos correlaciσn entre el peso de la muestra del alga y la frecuencia de gasterσpodos en ésta, R² = 0.0893 para sotavento, 0.0249 para barlovento y 0.0923 para datos combinados. Utilizando los métodos de ordenación polar se comprueba la similitud de las dos comunidades estudiadas. Estos resultados sostienen la hipótesis de que H. opuntia le ofrece a los organismos que viven en sus intersticios un microhábitat protegido del impacto del movimiento del agua, creando condiciones más homogéneas que las del hábitat donde encontramos creciendo el alga.

Shell occupation by the endemic western Atlantic hermit crab Isocheles sawayai (Diogenidae) from Caraguatatuba, Brazil / Ocupação de conchas pelo ermitão endêmico do Atlântico ocidental Isocheles sawayai (Diogenidae) em Caraguatatuba, Brasil

The aim of this study was to characterize the pattern of shell occupation by the hermit crab Isocheles sawayai Forest and Saint-Laurent, 1968, from the Caraguatatuba region. The percentage of shell types that were occupied and the morphometric relationships between hermit crabs and occupied shells were analyzed from systematized collections that were conducted monthly from July 2001 to June 2003. A total of 373 individuals were captured (297 males, 41 non-ovigerous females, 25 ovigerous females and 10 intersexes), occupying 17 species of gastropod shells. Stramonita haemastoma (Linnaeus, 1767) (49.87 percent) was the significantly most occupied species (χ2 = 89.30; P < 0.05) followed, with no significant difference, by Phalium granulatum (Born, 1778) (11.53 percent), Polinices hepaticus (Roding, 1798) (8.31 percent) and Cymatium parthenopeum (von Salis, 1793) (6.97 percent). All the morphometric relationships between hermit crabs and occupied shells showed high (r > 0.68) and significant (P < 0.05) correlation values, which is an important indication that in this I. sawayai population the animals occupied adequate shells. The high number of occupied shell species and relative plasticity indicated that, for the studied population, occupation is influenced by the shell availability.

O presente estudo caracterizou o padrão de ocupação de conchas de Isocheles sawayai Forest and Saint-Laurent, 1968, na região de Caraguatatuba. A porcentagem dos diferentes tipos de conchas ocupadas e as relações morfométricas entre os ermitões e as conchas ocupadas foram analisadas a partir de material de amostragem sistematizada, mensalmente, de julho/2001 a junho/2003. Foram capturados 373 indivíduos (297 machos, 41 fêmeas não-ovígeras, 25 fêmeas ovígeras e 10 indivíduos intersexo), ocupando 17 espécies de conchas de moluscos gastrópodes. Stramonita haemastoma (Linnaeus, 1767) (49,87 por cento) foi a espécie significativamente mais ocupada (χ2 = 89,30; p < 0,05) seguida, porém sem diferença significativa, por Phalium granulatum (Born, 1778) (11,53 por cento), Polinices hepaticus (Roding, 1798) (8,31 por cento) e Cymatium parthenopeum (von Salis, 1793) (6,97 por cento). Todas as relações morfométricas entre os ermitões e as conchas ocupadas apresentaram valores de coeficientes de correlação elevados (r > 0,68) e significativos (p < 0,05), o que é um importante indício de que, nessa população de I. sawayai, os animais ocupavam conchas adequadas. O elevado número de espécies de conchas ocupadas e a relativa plasticidade indicaram que, para a população estudada, a ocupação é influenciada pela disponibilidade de conchas.

La Familia Calyptraeidae en el Perú (Gastropoda: Caenogastropoda)

En el presente trabajo se realiza una revisión taxonómica de la familia Calyptraeidae Lamarck, 1809, en la costa Peruana. Se confirma la presencia de 17 especies de las 19 reportadas por diversos autores. Crepidula arenata (Broderip, 1834) es sinónimo de C. excavata (Broderip, 1834). Se da información sobre la distribución geográfica y algunas relaciones ecológicas.

In the present work the taxonomic of the family Calyptraeidae Lamarck, 1809 in the Peruvian coast are reviewed. The presence of 17 species of the 19 is confirmed reported by diverse authors. Crepidula arenata (Broderip, 1834) is synonymous of C. excavata (Broderip, 1834). Information on the distribution geographical and same relations ecological is presented.