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Sea spiders (Class Pycnogonida Latreille, 1810) are chelicerate arthropods, with an extraordinarily reduced body armed with eight to twelve elongated legs. A literature review of taxonomic and ecological studies of pycnogonids from Mexico identified 49 nominal species (~3.6% out of 1,335 species described worldwide). This low species richness is likely caused by limited taxonomic research and intermittent sampling and research efforts initially carried out by foreign scientists (1893-1996) and later by Mexican scientists. The present study investigates the latitudinal gradient of species richness of the pycnogonids associated with nine marine docks located between Cabo San Lucas (22°53'N) and Santa Rosalía (26°58'N) along the west coast of the Gulf of California, 22°53'N Mexico and provides a detailed morphological re-description of each nominal species using light and scanning electron microscopy. Nine nominal pycnogonid species and one unidentified species in the genus Tanystylum were collected and identified from the biological samples collected between 2011-2017. The highest pycnogonid species richness was recorded at Bahía de La Paz (seven species, 24°14'N) and the lowest species richness at Cabo San Lucas (one species) without an evident latitudinal species richness gradient. Anoplodactylus californicus Hall, 1912 and Ammothella spinifera Cole, 1904 were the most abundant species (52% of the total number of individuals). Tanystylum occidentale (Cole, 1904) and Nymphon apheles Child, 1979 were new geographical records for Mexico and Ammothella symbia Child, 1979 and A. californicus were new records for Baja California Sur state. Adding these new geographical records of pycnogonids increased the species richness previously recorded at Baja California Sur from 20 to 24 nominal species and for Mexico, the species richness increased from 49 to 51 nominal species.

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Temnocephala axenos Monticelli, 1898 was described based on specimens from an unidentified host collected in Blumenau, Santa Catarina, Brazil. Information about type locality was imprecise and the host was later identified as Aegla laevis (Latreille, 1818). However, it is known that A. laevis is not present on the eastern side of the Andes. Also, only histological preparations from one specimen studied by Monticelli are currently available in the Museum für Naturkunde Berlin, but it showed none of the taxonomic characters needed for the characterization of the species. Although the updated description of the species based on Uruguayan specimens, neither the author nor the several previous studies about the species showed a search for the type material, a resolution for the misidentification of the type host or the imprecise type locality due to the subsequent geographical division of the municipality cited in the description. The Uruguayan specimens were not even geographically close to the type locality and a neotype was not designed to validate the species' taxonomic status again. Specimens from Santa Catarina and Paraná States, Brazil, were studied, as well as restudied Argentinean specimens. The new data were compared with the update description of the species. The historical background and the discussion about geographical origins and hosts of the species, as well as a designation of a neotype, allow comparative material of the type locality and type host to exist, eliminating doubts about the identification of T. axenos.

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Ophryotrocha is the most speciose genus within Dorvilleidae, with species occurring in a great variety of environments around the globe. In Brazil, records of Ophryotrocha are scarce and no specific identification is provided for any of the records. Herein we describe a new species of Dorvilleidae, Ophryotrocha zitae sp. nov. Adult and larval specimens were found in the axis of a fragment of the cold-water coral Lophelia pertusa, sampled off São Paulos coast, at a depth of 245 m. Both forms are described and illustrated. This new species resembles O. puerilis, O. adherens and O. eutrophila, but can be distinguished based on differences in its mandible and on chaetae shape and arrangement.(AU)

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Ophryotrocha is the most speciose genus within Dorvilleidae, with species occurring in a great variety of environments around the globe. In Brazil, records of Ophryotrocha are scarce and no specific identification is provided for any of the records. Herein we describe a new species of Dorvilleidae, Ophryotrocha zitae sp. nov. Adult and larval specimens were found in the axis of a fragment of the cold-water coral Lophelia pertusa, sampled off São Paulo’s coast, at a depth of 245 m. Both forms are described and illustrated. This new species resembles O. puerilis, O. adherens and O. eutrophila, but can be distinguished based on differences in its mandible and on chaetae shape and arrangement.

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Abstract Epistyliasis has been characterized as an emergent disease which has a great impact on fish farms, especially on Oreochromis niloticus production systems. Although epidemiological important, information about the dispersion of these parasites and their mechanical vectors is scarce. The present study reported the cooccurrence of Epistylis sp. as an epibiont of Dolops carvalhoi, a parasitic crustacean of cultivated/wild specimens (from accidental release) of O. niloticus from a cage fish farm area in the Ilha Solteira Reservoir, Grande River, SP, Brazil. The co-occurrence of Epistylis sp. and D. carvalhoi, and their epibiont relationship registered in this study suppose that the Epistylis may use the crustaceans for dispersion and as mechanical vectors for the dissemination of diseases in wild and cultivated hosts. Moreover, exchange of parasites between wild and cultivated hosts is possible, considering both organisms (protozoan and argulid). Furthermore, the results of the present study demonstrate the need to monitor the areas adjacent to cage fish farms as a preventive measure for the dispersion of pathogens. This is the first report of epibiosis between Epistylis sp. and argulid parasites of cultivated and wild O. niloticus, contributing to knowledge about host-parasite specificity, geographical distribution, dispersion of etiological agents and epidemiology in aquaculture.

Resumo Epistilíase tem sido caracterizada como uma doença emergente de grande impacto nas pisciculturas, especialmente em sistemas de produção de Oreochromis niloticus. Embora seja importante epidemiologicamente, informações sobre a dispersão desses parasitas e seus vetores mecânicos são escassos. O presente estudo relata a coocorrência de Epistylis sp. como um epibionte de Dolops carvalhoi, um crustáceo parasita de espécimes cultivados e silvestres (de escapes acidentais) de O. niloticus em área de piscicultura de tanques-rede no reservatório de Ilha Solteira, Rio Grande, SP, Brasil. A coocorrência de Epistylis sp. e D. carvalhoi, e sua relação epibionte registrada neste estudo, supõem que Epistylis sp. possa utilizar os crustáceos para dispersão e como vetores mecânicos para a disseminação de doenças em hospedeiros silvestres e cultivados. Além disso, a troca de parasitas entre hospedeiros silvestres e cultivados é possível, considerando ambos os organismos (protozoários e argulídeos). Os resultados deste estudo, também demonstram a necessidade de monitorar as áreas adjacentes às pisciculturas como medida preventiva para a dispersão de patógenos. Este é o primeiro relato de epibiose entre Epistylis sp. e parasitas argulídeos de O. niloticus cultivados e silvestres, contribuindo para o conhecimento da especificidade parasitária do hospedeiro, distribuição geográfica, dispersão de agentes etiológicos e epidemiologia na aquicultura.

Assuntos

RESUMO

Epistyliasis has been characterized as an emergent disease which has a great impact on fish farms, especially on Oreochromis niloticus production systems. Although epidemiological important, information about the dispersion of these parasites and their mechanical vectors is scarce. The present study reported the cooccurrence of Epistylis sp. as an epibiont of Dolops carvalhoi, a parasitic crustacean of cultivated/wild specimens (from accidental release) of O. niloticus from a cage fish farm area in the Ilha Solteira Reservoir, Grande River, SP, Brazil. The co-occurrence of Epistylis sp. and D. carvalhoi, and their epibiont relationship registered in this study suppose that the Epistylis may use the crustaceans for dispersion and as mechanical vectors for the dissemination of diseases in wild and cultivated hosts. Moreover, exchange of parasites between wild and cultivated hosts is possible, considering both organisms (protozoan and argulid). Furthermore, the results of the present study demonstrate the need to monitor the areas adjacent to cage fish farms as a preventive measure for the dispersion of pathogens. This is the first report of epibiosis between Epistylis sp. and argulid parasites of cultivated and wild O. niloticus, contributing to knowledge about host-parasite specificity, geographical distribution, dispersion of etiological agents and epidemiology in aquaculture.(AU)

Epistilíase tem sido caracterizada como uma doença emergente de grande impacto nas pisciculturas, especialmente em sistemas de produção de Oreochromis niloticus. Embora seja importante epidemiologicamente, informações sobre a dispersão desses parasitas e seus vetores mecânicos são escassos. O presente estudo relata a coocorrência de Epistylis sp. como um epibionte de Dolops carvalhoi, um crustáceo parasita de espécimes cultivados e silvestres (de escapes acidentais) de O. niloticus em área de piscicultura de tanques-rede no reservatório de Ilha Solteira, Rio Grande, SP, Brasil. A coocorrência de Epistylis sp. e D. carvalhoi, e sua relação epibionte registrada neste estudo, supõem que Epistylis sp. possa utilizar os crustáceos para dispersão e como vetores mecânicos para a disseminação de doenças em hospedeiros silvestres e cultivados. Além disso, a troca de parasitas entre hospedeiros silvestres e cultivados é possível, considerando ambos os organismos (protozoários e argulídeos). Os resultados deste estudo, também demonstram a necessidade de monitorar as áreas adjacentes às pisciculturas como medida preventiva para a dispersão de patógenos. Este é o primeiro relato de epibiose entre Epistylis sp. e parasitas argulídeos de O. niloticus cultivados e silvestres, contribuindo para o conhecimento da especificidade parasitária do hospedeiro, distribuição geográfica, dispersão de agentes etiológicos e epidemiologia na aquicultura.(AU)

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Recent investigations have demonstrated that unusually 'hairy' yeti crabs within the family Kiwaidae associate with two predominant filamentous bacterial families, the Epsilon and Gammaproteobacteria. These analyses, however, were based on samples collected from a single body region, the setae of pereopods. To more thoroughly investigate the microbiome associated with Kiwa puravida, a yeti crab species from Costa Rica, we utilized barcoded 16S rRNA amplicon pyrosequencing, as well as microscopy and terminal restriction fragment length polymorphism analysis. Results indicate that, indeed, the bacterial community on the pereopods is far less diverse than on the rest of the body (Shannon indices ranged from 1.30-2.02 and 2.22-2.66, respectively). Similarly, the bacterial communities associated with juveniles and adults were more complex than previously recognized, with as many as 46 bacterial families represented. Ontogenetic differences in the microbial community, from egg to juvenile to adult, included a dramatic under-representation of the Helicobacteraceae and higher abundances of both Thiotrichaceae and Methylococcaceae for the eggs, which paralleled patterns observed in another bacteria-crustacean symbiosis. The degree to which abiotic and biotic feedbacks influence the bacterial community on the crabs is still not known, but predictions suggest that both the local environment and host-derived factors influence the establishment and maintenance of microbes associated with the surfaces of aquatic animals.

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Stalked barnacles Octolasmis lowei Darwin, 1851 are frequently found attached to decapod crustaceans. Their epibiotic association depends on many factors, which are mainly related to characteristics of the host's biology. This study evaluated the infestation and distribution of stalked barnacles in the branchial chambers of crabs, and analyzed the data with respect to the host's sex, maturity stage, molt cycle and size. The crab species Arenaeus cribrarius Lamarck, 1818, Callinectes danae Smith, 1869, Callinectes ornatus Ordway, 1863, Hepatus pudibundus Herbst, 1785, Libinia ferreirae Brito Capello, 1871, and Persephona punctata Linnaeus, 1758 were sampled and found to be infested by O. lowei. No juvenile crabs were infested. The prevalence of infestation by O. lowei was significantly different among C. danae, C. ornatus, and H. pudibundus males and females. All infested hosts were in the intermolt period. The mean size of infested crabs was larger than that observed for non-infested individuals. Internally, stalked barnacles were concentrated on the central gills or walls and floor of branchial chambers, suggesting that these gills provide more favorable conditions for the settlement and development of these epibionts. These results highlight the relationship between epibiont infestation and host biology, as well as the role of decapod crustaceans as a suitable substrate for the development of stalked barnacle O. lowei.

RESUMO

Stalked barnacles Octolasmis lowei Darwin, 1851 are frequently found attached to decapod crustaceans. Their epibiotic association depends on many factors, which are mainly related to characteristics of the host's biology. This study evaluated the infestation and distribution of stalked barnacles in the branchial chambers of crabs, and analyzed the data with respect to the host's sex, maturity stage, molt cycle and size. The crab species Arenaeus cribrarius Lamarck, 1818, Callinectes danae Smith, 1869, Callinectes ornatus Ordway, 1863, Hepatus pudibundus Herbst, 1785, Libinia ferreirae Brito Capello, 1871, and Persephona punctata Linnaeus, 1758 were sampled and found to be infested by O. lowei. No juvenile crabs were infested. The prevalence of infestation by O. lowei was significantly different among C. danae, C. ornatus, and H. pudibundus males and females. All infested hosts were in the intermolt period. The mean size of infested crabs was larger than that observed for non-infested individuals. Internally, stalked barnacles were concentrated on the central gills or walls and floor of branchial chambers, suggesting that these gills provide more favorable conditions for the settlement and development of these epibionts. These results highlight the relationship between epibiont infestation and host biology, as well as the role of decapod crustaceans as a suitable substrate for the development of stalked barnacle O. lowei.

RESUMO

Stalked barnacles Octolasmis lowei Darwin, 1851 are frequently found attached to decapod crustaceans. Their epibiotic association depends on many factors, which are mainly related to characteristics of the host's biology. This study evaluated the infestation and distribution of stalked barnacles in the branchial chambers of crabs, and analyzed the data with respect to the host's sex, maturity stage, molt cycle and size. The crab species Arenaeus cribrarius Lamarck, 1818, Callinectes danae Smith, 1869, Callinectes ornatus Ordway, 1863, Hepatus pudibundus Herbst, 1785, Libinia ferreirae Brito Capello, 1871, and Persephona punctata Linnaeus, 1758 were sampled and found to be infested by O. lowei. No juvenile crabs were infested. The prevalence of infestation by O. lowei was significantly different among C. danae, C. ornatus, and H. pudibundus males and females. All infested hosts were in the intermolt period. The mean size of infested crabs was larger than that observed for non-infested individuals. Internally, stalked barnacles were concentrated on the central gills or walls and floor of branchial chambers, suggesting that these gills provide more favorable conditions for the settlement and development of these epibionts. These results highlight the relationship between epibiont infestation and host biology, as well as the role of decapod crustaceans as a suitable substrate for the development of stalked barnacle O. lowei.

RESUMO

Colacium vesiculosum (Euglenophyceae) is an epibiont common on planktonic microcrustaceans of continental waters. The interaction between epibionts and substrate organisms is not very well known, particularly in subtropical environments of South America. In the present work, we analyzed the prevalence, density, biomass and attachment sites of C. vesiculosum on planktonic microcrustaceans from Paiva Lake, a subtropical lake of Argentina. With the aim to evaluate whether epibionts affect the filtering rates of Notodiaptomus spiniger, the dominant planktonic crustacean, we carried out bioassays using phytoplankton <53µm. Crustaceans were sampled using a PVC tube (1.2m long and 10cm in diameter), filtering 50L of water through a 53µm-mesh. Microcrustaceans were counted in Bogorov chambers under a stereoscopic microscope. The infested organisms were separated and observed with a photonic microscope to determine density and biovolume of epibionts, by analyzing their distribution on the exoskeleton. The prevalence of C. vesiculosum was higher in adult crustaceans than in their larvae and juveniles. The most infested group was that of calanoid copepods, related to their high density. The attachment sites on the exoskeleton were found to be the portions of the body which have a higher probability of encounter with epibionts during locomotion and feeding, i.e., antennae and thoracic legs in copepods, and thoracic legs and postabdomen in cladocerans. The similar values found in the filtering rate of infested and uninfested individuals of N. spiniger and the constant prevalence (<40%) of epibiont algae, suggest that C. vesiculosum does not condition the life of planktonic crustaceans of Paiva Lake. Rev. Biol. Trop. 59 (3): 1295-1306. Epub 2011 September 01.

Colacium vesiculosum Ehrenberg (Euglenophyceae) es un epibionte común en microcrustáceos del plancton de aguas continentales. La interacción epibiontes y organismo substrato es poco conocida, particularmente en ambientes subtropicales de América del Sur. Se analiza la prevalencia, densidad, biomasa y sitios de adhesión de C. vesiculosum en microcrustáceos planctónicos de un lago subtropical de Argentina. Con el fin de evaluar si los epibiontes afectan la tasa de filtración de Notodiaptomus spiniger Brian, crustáceo dominante del zooplancton, se realizaron bioensayos utilizando el fitoplancton <53µm. Los crustáceos fueron muestreados con un tubo de PVC (1m de largo, 10cm de diámetro) filtrándose 50L de agua a través de una red de 53µm de abertura de malla. El recuento de los microcrustáceos se realizó en cámaras de Bogorov bajo microscopio estereoscópico. Los organismos infectados fueron separados y observados al microscopio fotónico para determinaciones de densidad y biovolumen de los epibiontes, y su distribución en el exoesqueleto. La prevalencia de C. vesiculosum fue mayor en crustáceos adultos que en estadíos larvales y juveniles. El grupo más infestado fue el de los copépodos calanoideos en relación con su alta densidad. Los sitios de adhesión sobre el exoesqueleto fueron las regiones del cuerpo que durante la locomoción y alimentación tienen mayor probabilidad de encuentro con los epibiontes: antenas y patas toráxicas en copépodos, patas toráxicas y postabdomen en cladóceros. Valores similares en la tasa de filtración entre individuos infestados y no infestados de N. spiniger y la constante prevalencia (<40%) del alga epibionte sugieren que C. vesiculosum no condicionaría la vida de los microcrustáceos planctónicos del lago Paiva.

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