Desove y desarrollo intracapsular del caracol marino Hexaplexnigritus (Neogastropoda: Muricidae) en laboratorio / Spawning and intracapsular development of the marine snail Hexaplex nigritus (Neograstropoda: Muricidae) in the laboratory

Introducción: El caracol marino Hexaplex nigritus es un murícido fuertemente explotado en el Golfo de California para consumo y artesanías. Cuando se reproducen, los adultos se agregan en forma de arrecifes artificiales facilitando su identificación y extracción, lo cual, ha mermado su población en dicha zona. Objetivo: Investigar el desove y desarrollo intracapsular y larvario de esta especie como herramientas para su producción en cautiverio con fines de repoblamiento. Métodos: Se recolectaron 18 progenitores que fueron mantenidos en un sistema cerrado con parámetros y alimentación controladas durante abril 2017 hasta septiembre 2018. Se registró: crecimiento de progenitores, desove de masas ovígeras, cantidad de cápsulas y número de embriones y larvas dentro de las cápsulas. La temperatura de incubación fue de 28.2 ± 1.5 °C. Las principales estructuras morfológicas de embriones y larvas fueron documentadas conforme su desarrollo. Resultados: El desarrollo embrionario intracapsular y de la larva velígera hasta su asentamiento tuvieron una duración de 14-15 y 31-32 días, respectivamente. Cada hembra de 80-88 mm de longitud produjo alrededor de 4 masas ovígeras, 627 cápsulas y 663 993 larvas velígeras extracapsulares por año. Conclusiones: La fácil adaptación y el potencial reproductivo mostrado por H. nigritus en laboratorio se presentan como estrategias promisorias para su repoblación y conservación.

Introduction: The marine snail Hexaplex nigritus is a heavily exploited muricid in the Gulf of California for consumption and handcrafts. When they reproduce, adults aggregated in the form of artificial reefs facilitating their identification and extraction, situation that has reduced their population in that area. Objective: In order to investigate the spawning and intracapsular and larval development of this species as tools for its production in captivity for repopulation purposes. Methods: Eighteen brooders were collected and kept in a closed system with controlled parameters and feeding from April 2017 to September 2018. Growth of parents, spawning of ovigerous masses, number of capsules, and number of embryos and larvae within the capsules, were registered. The main morphological structures of embryos and larvae were documented according to their development. Results: Intracapsular embryonic development and veliger larva until its establishment lasted 14-15 and 31-32 days, respectively. Each 80-88 mm length female produced around 4 ovigerous masses, 627 capsules and 663 993 extracapsular veliger larvae per year. Conclusions: Easy adaptation and reproductive potential shown by H. nigritus in the laboratory are presented as promising strategies for its repopulation and conservation.

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).

Cryptosporidium parvum en gastrópodos silvestres como bioindicadores de contaminación fecal en ecosistemas terrestres / Cryptosporidium parvum in wild gastropods as bioindicators of fecal contamination in terrestrial ecosystems

Cryptosporidium sp oocysts were detected in snails (Helix aspersa Milller) and slug (Deroceras reticulatum Milller) from the Valparaiso Region, Chile. Snails and slug were collected from public squares and private domestic gardens. Cryptosporidium sp oocysts were recovered from faeces of both species. Ziehl Neelsen stain, nested PCR, and sequencing analysis demonstrated a profile similar to that described for genotype C or 2 of the parasite. These results demonstrate that snails and slug could act as a reservoir and mechanic vector of C. parvum infection for humans and animals. Moreover, gastropods could serve as bioindicators of fecal soil contamination.

Se detectó ooquistes de Cryptosporidium sp en caracoles (Helix aspersa Müller) y babosas (Deroce-ras reticulatum Müller) de la Región de Valparaíso, Chile. La recolección de caracoles y babosas se efectuó en parques públicos y jardines de diferentes hogares. Los ooquistes de Cryptosporidium sp fueron recuperados de las deposiciones de ambas especies. Después de la tinción de Ziehl Neelsen y la RPC anidada, el análisis de secuenciación demostró un patrón similar a lo descrito para el genotipo C o 2 del parásito. Estos resultados demuestran que los caracoles y babosas podrían actuar como reservorio y vectores mecánicos de la infección por Cryptosporidium. parvum para humanos y animales. Además, estos gastrópodos podrían ser usados como bio-indicadores de contaminación fecal del suelo.

Dynamics and ecology of an Indo-Pacific conch, Conomurex persicus (Mollusca: Gastropoda) in southeastern Turkey

Conomurex persicus, one of the tropical conchs, has been introduced to one of the subtropical regions, the northeastern Mediterranean Sea, and invaded sandy bottoms between 1 and 10 m deep. Population dynamics were studied from specimens collected with a standard dredge (60 x 15 cm mouth opening, 0.5 x 0.5 cm eye opening of net). Samples of C. persicus were collected monthly along the 5 and 10 m depth contours off Erdemli, Mersin, Turkey, in February and May 2000. Intra-annual density depended on salinity levels, while inter-annual density was correlated with bottom water temperature. Specimens underwent spring emergences and winter burial and sheltering (disappearance). Emergence took place in March when temperatures rose and the disappearance occurred in October-November when temperatures dropped. Adults live at 10 m, juveniles are recruited at a 5 m depth. Recruitment began in April and continued for the next 6 months. In contrast to shell width or shell lip thickness, shell length was not a convenient index for estimation of growth parameters. Annual production and mortality were calculated to be 7.86 g m-2 and 3.80 g m-2, respectively, in April-November.

El gastrópodo tropical Conomurex persicurs, ha sido introducido a una región subtropical, el noreste del Mar Mediterráneo, y ha invadido los fondos arenosos en un rango de profundidad de 1 a 10 m. Se estudiarion las dinámicas poblacionales a partir de especímenes recolectados mediante un dragado estándard (60 x 15 cm de apertura de entrada y 0.5 x 0.5 cm de tramado). Muestras de C. persicus fueron recolectadas mensualmente a produndidades de 5 y 10 m en las cercanías de Erdemil, Mersin, Turkey, en los meses de febrero y mayo del año 2000. La densidad dentro de un mismo año depende de los niveles de salinidad, mientras que al comparar años distintos está correlacionada con la temperatura del agua.