Morphology and molecular phylogeny of Heterobothrium lamothei (Monogenea: Diclidophoridae), a gill parasite infecting the tiger puffer fish Lagocephalus sceleratus (Tetraodontidae) / Morfologia e filogenia molecular de Heterobothrium lamothei (Monogenea: Diclidophoridae), um parasita das guelras que infecta o peixe tigre pufferLagocephalus sceleratus (Tetraodontidae)

Members of the family Diclidophoridae are potentially dangerous species for the puffer fish aquaculture worldwide. They are parasitic polyopisthocotyleans, with a posterior haptor equipped with clamps for attachment to the host's surface, allowing the worm to resist the flow of water to maintain its position on gills. The anterior body of the worm is deformable, allows the worm to feed on blood sucked from fish gills. The present study is the first description of a Heterobothrium species from the gills of the tiger puffer Lagocephalus sceleratus (Tetraodontidae) from the coasts of the Arabian Gulf at Jubail, Saudi Arabia morphologically by light microscopy as well as by molecular analysis of the parasite partial 28S rRNA through multiple sequence alignments and phylogeny by maximum likelihood analysis which is provided for the first time for the described species. Seventeen tiger puffer fish were captured alive from marine water off Saudi Arabia; gills were separated and further examined for parasitic infection. Nine fish were found infected with a monogenean parasite which was robust, equipped by two buccal organs at the tapered anterior end; the posterior haptor was rectangular with four symmetrically arranged clamps, with no isthmus. Marginal hooks absent. Ovary elongated, U-shaped, testes numerous, irregularly shaped and extended from the posterior part of the ovary to the anterior margin of the haptor. Copulatory organ muscular, as a spherical cup armed with 12 to 15 genital hooks. The molecular analysis of the parasite 28s rRNA and phylogeny revealed a percentage of identities between 87.47-89.09%, with Diclidophoridae species within the monophyletic clade of Mazocraeidea where a maximum percentage of 89.09% were obtained for the morphologically different sister taxon H. okamotoi. The results obtained from molecular analysis are consistent with the conclusions drawn from morphological classification where that the parasite recorded was morphologically similar to H. lamothei which was not characterized by molecular analysis before. The recovered sequences were deposited into the GeneBank under accession number MT322610.(AU)

Os membros da família Diclidophoridae são espécies potencialmente perigosas para a aquicultura de peixes puffer em todo o mundo. Eles são parasitas poliopisthocotyleans, com uma hélice posterior equipada com pinças para fixação na superfície do hospedeiro, permitindo que o verme resista ao fluxo de água para manter sua posição nas brânquias. O corpo anterior do verme é deformável, e permite que o verme se alimente de sangue sugado das guelras dos peixes. O presente estudo é a primeira descrição de uma espécie Heterobothrium das guelras do tigre Lagocephalus sceleratus (Tetraodontidae) das costas do Golfo Arábico em Jubail, Arábia Saudita, usando morfologia por microscopia leve, bem como análise molecular do rRNA parcial do parasita 28S através de alinhamentos de sequências múltiplas e filogenia por análise de máxima verossimilhança que é fornecida pela primeira vez para as espécies descritas. Dezessete peixes tigre puffer foram capturados vivos da água marinha da Arábia Saudita; as brânquias foram separadas e mais tarde examinadas para detecção de infecção parasitária. Nove peixes foram encontrados infectados por um parasita monogênio robusto, equipado por dois órgãos bucais na extremidade anterior afilada; o hortetor posterior era retangular com quatro pinças dispostas simetricamente, sem istmo. Ausência de ganchos marginais. Ovário alongado, em forma de U, testículos numerosos, de forma irregular e estendido desde a parte posterior do ovário até a margem anterior do hortelino. Órgão copulatório muscular, como um copo esférico armado com 12 a 15 ganchos genitais. A análise molecular do parasita 28s rRNA e filogenia revelou uma porcentagem de identidades entre 87,47-89,09%, com espécies Diclidophoridae dentro do clade monofilético de Mazocraeidea onde uma porcentagem máxima de 89,09% foi obtida para o táxon-irmão morfologicamente diferente H. okamotoi. Os resultados obtidos da análise molecular são consistentes com as conclusões tiradas da classificação morfológica onde o parasita registrado era morfologicamente semelhante ao H. lamothei que não era caracterizado pela análise molecular antes. As sequências recuperadas foram depositadas no GeneBank sob o número de acesso MT322610.(AU)

First record of Unibarra paranoplatensis Suriano & Incorvaia, 1995 (Dactylogyridae: Monogenea) on Sorubim lima (Siluriformes: Pimelodidae) from Brazil / Primeiro registro de Unibarra paranoplatensis Suriano & Incorvaia, 1995 (Dactylogyridae: Monogenea) em Sorubim lima (Siluriformes: Pimelodidae) do Brasil

Abstract The aim of this study was to report the first occurrence of Unibarra paranoplatensis Suriano & Incorvaia, 1995 on Sorubim lima Bloch & Schneider, 1801 from Brazil. On the gills of S. lima, U. paranoplatensis presented similar morphological and morphometric features to those described for conspecifics infesting Zungaro zungaro Humboldt, 1921 except the length, which was higher in the present study, as well as ventral bar shape that was V-shaped open, and with the upper and lower end of the rod relatively sinuous. This study expands the geographic distribution of U. paranoplatensis to Brazil, a parasite that has a wide occurrence across South America.

Resumo O objetivo deste estudo foi relatar a primeira ocorrência de Unibarra paranoplatensis Suriano & Incorvaia, 1995 em Sorubim lima Bloch & Schneider, 180 do Brasil. Nas brânquias de S. lima do Rio Acre, estado do Acre (Brasil), U. paranoplatensis apresentou características morfológicas e morfométricas similares àquelas descritas para Zungaro zungaro Humboldt, 1921; com exceção do comprimento que foi maior no presente estudo e formato da barra ventral que foi em forma de V aberto, com a extremidade superior e inferior da barra relativamente sinuosa. Este estudo amplia a distribuição geográfica de U. paranoplatensis para o Brasil, um parasito com distribuição na América do Sul.

A new species of Tereancistrum (Monogenea, Dactylogyridae) from the gills of three Leporinus species (Characiformes, Anostomidae) and a revised description of Tereancistrum parvus

ABSTRACT The present study describes Tereancistrum flabellum n. sp. (Dactylogyridae, Ancyrocephalinae) from the gills of the anostomid fishes Leporinus friderici, Leporinus amblyrhynchus and Leporinus elongatus from two freshwater ecosystems in the south east of Brazil. This new species is mainly characterized by the morphology of the copulatory complex (such as the MCO base formed by two fan-shaped structures, and accessory piece flattened, curved, rigid and channeled), a dorsal anchor with a well-developed superficial and inconspicuous deep root, and the shape of the accessory anchor sclerite with small spathulate termination. Tereancistrum flabellum n. sp. is the first record of a dactylogyrid from L. amblyrhynchus. The description of Tereancistrum parvus is also emended to correct and complement previous descriptions and the species is reported for the first time in Schizodon nasutus.

Apedunculata discoidea gen. n., sp. n. (Monogenea: Dactylogyridae) parasitic on Prochilodus lineatus (Valenciennes, 1837) (Characiformes: Prochilodontidae) from southeastern Brazil / Apeduncullata discoidea gen. n., sp. n. (Monogenea: Dactylogyridae) parasito de Prochilodus lineatus (Valenciennes, 1837) (Characiformes: Prochilodontidae) do sudeste do Brasil

A new species of dactylogyrid monogenean, Apedunculata discoidea gen. n., sp. n. is described and illustrated from the gills of the freshwater fish Prochilodus lineatus (Valenciennes, 1837) in pisciculture ponds from Pirassununga, São Paulo, Brazil. Diagnostic characters of the new genus and species are: 1) vagina dextrolateral slightly sclerotised, opening anteriorly at level of copulatory complex; 2) copulatory organ coiled with two counterclockwise rings; 3) Accessory piece distal and not articulated; 4) body disk-shaped, lacking a peduncle.

Uma espécie nova de monogenético dactilogirídeo, Apedunculata discoidea gen. n., sp. n. parasita das brânquias do peixe de água doce Prochilodus lineatus (Valenciennes, 1837) proveniente de pisciculturas de Pirassununga, São Paulo, Brasil, é descrita e ilustrada. As características diagnósticas do novo gênero e da nova espécie são: 1) vagina dextrolateral levemente esclerotizada, com abertura ao nível do complexo copulatório; 2) órgão copulatório em espiral com duas voltas no sentido anti-horário; 3) peça acessória distal e não articulada; 4) corpo com formato de disco e sem pedúnculo.

Embryonic development of Girardia tigrina (Girard, 1850) (Platyhelminthes, Tricladida, Paludicola) / Desenvolvimento embrionário de Girardia tigrina (Girard, 1850) (Platyhelminthes, Tricladida, Paludicola)

The embryonic development of freshwater triclads is mainly known from studies of species of Dendrocoelum, Planaria, Polycelis, and, more recently, Schmidtea. The present study characterizes the development of Girardia tigrina (Girard, 1850) by means of optical microcopy using glycol methacrylate semi-thin sections. 94 cocoons were collected in the period from laying to hatching, with intervals of up to twenty-four hours. The sequence of morphological changes occurring in the embryo permitted the identification of nine embryonic stages. At the time of cocoon laying, numerous embryos were dispersed among many yolk cells, with a rigid capsule covering the entire cocoon. In the first stage (approx. up to 6 hours after cocoon laying), yolk cells and embryonic cells showed random distribution. Stage II (between 12 and 24 hours after cocoon laying) is characterized by aggregates of blastomeres, which later aggregate forming an enteroblastula. Approximately 2 days after cocoon laying (stage III), formation of the embryonic epidermis and embryonic digestive system took place, the latter degenerating during the subsequent stage. Stage V (until the fourth day) is characterized by the formation of the definitive epidermis. Between 4 and 6 days after laying, organogenesis of the definitive inner organs starts (stage VI). Approximately 14 days after laying (stage IX), formation of the nervous system is completed. At this stage, the embryo shows similar characteristics to those of newly hatched juveniles. The hatching of Girardia tigrina occurs in the period between twelve to twenty-two days after cocoon laying.

O desenvolvimento embrionário dos tricladidos é conhecido, fundamentalmente, por estudos realizados em espécies de Dendrocoelum, Planaria, Polycelis e, mais recentemente, Schmidtea. O presente estudo descreve o desenvolvimento embrionário de Girardia tigrina (Girard, 1850), a partir de análises realizadas em cortes histológicos seriados e semifinos de glicol-metacrilato, ao microscópio óptico. Noventa e quatro casulos foram coletados no período entre a postura e a eclosão, em intervalos de até vinte e quatro horas. A seqüência das modificações morfológicas no embrião permitiu a identificação de nove estágios embrionários. Na postura dos casulos, envoltos por uma cápsula rígida, observam-se numerosos embriões dispersos entre grande quantidade de células vitelinas. No estágio I (aproximadamente até 6 horas após a postura), as células vitelinas e as embrionárias mostram uma distribuição aleatória. O estágio II (entre 12 e 24 horas após a postura) caracteriza-se pela formação de agrupamentos de blastômeros, os quais posteriormente formam uma enteroblástula. Aproximadamente dois dias após a postura (estágio III), ocorre a formação da epiderme e do sistema digestivo embrionário, sendo que este último degenera no estágio seguinte. O estágio V (até o quarto dia após a postura) caracteriza-se pela formação da epiderme definitiva. Entre o quarto e o sexto dia posteriores à postura, começa a organogênese dos órgãos internos definitivos (estágio VI). Aproximadamente catorze dias após a postura (estágio IX), completa-se a formação do sistema nervoso. Neste estágio, o embrião já apresenta características similares aos espécimes juvenis. A eclosão de Girardia tigrina ocorre entre doze e vinte e dois dias após a postura dos casulos.

New data on species of Demidospermus (Dactylogyridae: Monogenea) parasitizing fishes from the reservoir of the Itaipu Hydroelectric Power Station, Parana State, Brazil, with new synonymies / Novos dados sobre Demidospermus (Dactylogyridae: Monogenea) parasitas de peixes do reservatório da Usina Hidrelétrica de Itaipú, Estado do Paraná, Brasil, com novas sinonimias

Eight known species of Demidospermus (Dactylogyridae, Monogenea) were collected from siluriform fishes from reservoir of the Itaipu Hydroelectric Power Station, Paraná, Brazil. Four of them are recorded for the first time in Brazil, enlarging their geographical distribution: Demidospermus armostus, Demidospermus anus, Demidospermus bidiverticulatum and Demidospermus valenciennesi. Demidospermus labrosi is synonymized with Demidospermus cornicinus and Demidospermus mandi with Demidospermus leptosynophallus and reported from two new hosts. Demidospermus paravalenciennesi and Demidospermus uncusvalidus were also collected.

Oito espécies de Demidospermus (Dactylogyridae, Monogenea) foram coletadas de peixes Siluriformes do reservatório da Usina Hidrelétrica de Itaipú, Paraná, Brasil. Quatro dessas são registradas pela primeira vez no Brasil, aumentando sua distribuição geográfica: Demidospermus armostus, Demidospermus anus, Demidospermus bidiverticulatum e Demidospermus valenciennesi. Demidospermus labrosi é considerada sinônima de Demidospermus cornicinus e Demidospermus mandi sinônima de Demidospermus leptosynophallus e registradas em dois novos hospedeiros. Foram também coletados exemplates de Demidospermus paravalenciennesi e Demidospermus uncusvalidus.

Organized Filaments in the adhesive system of Macrostomum tuba Graff, 1882 ( Platyhelminthes, Macrostomida)

The adhesive organs or “duo-gland adhesive organs” of platyhelminths are formed by a specialized epithelialcell and extensions of two gland cells. These organs are used for temporary fixation of the organism tosurfaces in aquatic habitats. The mechanisms involved in adhesion to and release from a given surfacedepend on secretions produced by the glands; less is known about the involvement of cytoplasmic filamentsin the anchoring cell itself. In this study, we examined the structure of the adhesive organs present in thetail plate of Macrostomum tuba Graff, 1882 (Platyhelminthes, Macrostomida), a freshwater, free-livingflatworm. Scanning and transmission electron microscopy allowed elucidation of the three-dimensionalorganization of the adhesive system, especially of the microvilli that formed the outer collar (or papilla),which was endowed with a fibrous core. Electrical stimulation caused the flatworms to extend their papillaeabove the ciliated surface. The use of tannin- and diamine-containing fixatives showed that the filamentousarray contained tonofilaments and actin filaments. Tonofilaments concentrate in the axis of each microvillus;actin filaments, about 7-8 nm thick, spread out towards the periphery. Scanning images demonstrated thefinger-like shape of the papillae, about 7-8 ìm high, with a terminal opening. Microvilli followed a straightcourse along the surface.

Histological processing techniques for the study of Dugesiidae development (Platyhelminthes, Tricladida, Paludicola)

The objective of the present study was to adapt techniques for the histological processing of Dugesiidae cocoons for the study of embryo development. The cocoons were fixed with formalin, SUSA, Bouin or paraformaldehyde/glutaraldehyde and subsequently embedded in Paraplast or glycol methacrylate (Historesin). Paraplast embedding yielded reasonable results only after the cocoon was perforated or fixed for a prolonged period of time using softening techniques with acid solutions. When the SUSA or Bouin fixative and Historesin embedding techniques were used the results were good for light microscopical analysis. Fixation with paraformaldehyde/glutaraldehyde and glycol methacrylate embedding resulted in better tissue preservation, and did not require prolonged fixation or softening techniques. Thus, we suggest this technique for light microscopical analysis of embryo development in Dugesiidae

First report of Temnocephala brevicornis Monticelli 1889 (Temnocephalidae: Platyhelminthes) in Argentina

Temnocephala brevicornis Monticelli 1889, ectosymbiont of Hydromedusa tectifera Cope 1869, is reported for the first time for Argentina. Numerous temnocephalans from Arroyo Villoldo in the locality of Magdalena, Buenos Aires, Argentina were stained in toto to be studied. This commensal species in turtles was originally cited in association with Hydromedusa maximiliani (Mikan) and Hydraspis radiolata Mikan in Brazil. Afterwards, it was found on other fresh water turtle species in Brazil and Uruguay.