A new species of Hysterothylacium (Ascaridoidea, Anisakidae) parasitic in Zenopsis conchifer (Zeiformes, Zeidae) from Argentinean waters

A new species of parasitic nematode, Hysterothylacium spirale sp. nov. (Ascaridoidea, Anisakidae), is described based on specimens collected from the intestine and pyloric caeca of the silvery john dory Zenopsis conchifer (Lowe) (Zeiformes, Zeidae), from the Argentinean Shelf (35°05´-40°46´S, 53°03´-58°07´W). Among the 66 valid species described so far in the genus, the new species most closely resembles H. zenis (Baylis, 1929). Both species, apparently specific for fishes of the family Zeidae, share the shape of the dorsal lip, the long expanded lateral alae originating from subventral interlabia and the ornamentation of the tail tip, as well as general morphometry. The combination of these shared features distinguishes both species from all congeners so far known. However, the new species is distinguishable from H. zenis by having shorter interlabia, and consequently the lateral alae originating more posteriorly, shorter spicules, a smaller number of postcloacal papillae and the presence of two pairs of double postcloacal papillae.Fil: Rossin, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Datri, Luciana L.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Incorvaia, Inés Silvia. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Timi, Juan Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Merizocotyle euzeti sp. N. (Monogenea: Monocotylidae) from the nasal tissue of three deep sea skates (Rajidae) in the Southwestern Atlantic Ocean

A new species of Merizocotyle Cerfontaine, 1894 (Monogenea: Monocotylidae) is described from the nasal tissues of three deep sea rajid skates: the southern thorny skate, Amblyraja doellojuradoi (Pozzi), broadnose skate, Bathyraja brachyurops (Fowler), and yellownose skate, Zearaja chilensis (Guichenot), collected off Buenos Aires Province, Argentina, southwest Atlantic Ocean. Two additional species of sympatric rajid, the white-dotted skate, Bathyraja albomaculata (Norman), and the Patagonian skate, Bathyraja macloviana (Norman), were also examined but no merizocotylines were found. The taxonomy of the Merizocotylinae is not widely accepted and, as a result, the status of Thaumatocotyle and Mycteronastes, and their proposed synonymy with Merizocotyle are currently under discussion. The new species differs from its congeners by having a unique haptoral structure, 6 peripheral loculi that are asymmetrically arranged (one much smaller, indistinctly located in the left or right side of the haptor). The presence of the new species in three sympatric species of Rajidae belonging to distinct genera and subfamilies, as well as its absence in sympatric congenerics indicates the lack of phylogenetic host specificity. Host ecology and geographical distribution appear to be more important than host phylogeny in determining the distribution of this parasite across potential hosts in the region. This constitutes the first record of Merizocotyle in the southwestern Atlantic Ocean.Fil: Irigoitia, Manuel Marcial. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Cantatore, Delfina María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Delpiani, Gabriela Elina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ictiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Incorvaia, Inés Silvia. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Lanfranchi, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Timi, Juan Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Nematodes parásitos como indicadores biológicos en las especies Macruronus magellanicus y Merluccius hubbsi (Pisces: gadiformes)

Se estudiaron los nematodes parásitos de Macruronus magellanicus (merluza de cola) y Merluccius hubbsi (merluza común) procedentes de campañas de investigación en el sector comprendido entre 34° y 55°S del Atlántico Sudoccidental. Se identificaron estadios adultos pertenecientes a las especies Hysterothylacium aduncum, Ascarophis marina e Ichthyofilaria argentinensis y larvales pertenecientes a H. aduncum, Anisakis simplex y Contracaecum aduncum. Se hallaron nematodes en diferentes estadios de desarrollo, dentro de las formas adultas las especies H. aduncum, Ascarophis marina e Ichthyofilaria argentinensis y dentro de las formas larvales H. aduncum, Anisakis simplex y Contracaecum sp. Por la plasticidad hospedatoria de H. aduncum se realizó un análisis de componentes principales de los caracteres morfométricos aportados por diferentes autores en diversas regiones. Los machos presentaron una mayor variabilidad que las hembras, hallándose éstas últimas dentro del grupo promedio. El análisis indica además que el parásito descripto en el presente trabajo constituye una identidad asimilable al H. aduncum mencionado para otras regiones. Se comprobó que H. aduncum presenta alometría negativa; a medida que aumenta la longitud total disminuye la velocidad de crecimiento de los caracteres utilizados en las diagnosis. Se estudió la reacción de los tejidos en los ejemplares parasitados de M. hubbsi. Anisakis sp. Resultó ser el más patógeno por el alto grado de reacción inflamatoria que provoca. Se seleccionaron los nematodes que podrían ser utilizados como indicadores biológicos.Facultad de Ciencias Naturales y Muse

Evaluating the usefulness of natural tags for host population structure in chondrichthyans: parasite assemblages of Sympterygia bonapartii (Rajiformes: Arhynchobatidae) in the Southwestern Atlantic

The usefulness of parasite tags for population discrimination of elasmobranch hosts remains largely unexplored. In order to assess the existence of different populations of Sympterygia bonapartii in the Southwestern Atlantic using its parasites as biological tags and to evaluate their usefulness as indicators for chondrichthyan hosts, we analysed data on assemblages of both long-lived and short-lived parasites of 193 skates distributed in eight samples caught at different seasons, years, depths and latitudes. A total of 6527 metazoan parasites, belonging to 19 species, was recorded. Only three species were long-lived, being therefore suitable biological tags, and they were used to assess the population structure of S. bonapartii. As a result, three host populations were identified (one Bonaerensean and two Patagonian). Distance-based multiple linear regressions (DistLM) evidenced that latitude was the most important predictor of parasite distribution, confirming the value of long-lived species as biological tags. When short-lived parasites were analysed, most samples differed from each other. Furthermore, a bathymetric rather than a latitudinal pattern was observed across samples, which was associated with reproductive migrations displayed by S. bonapartii. DistLM analyses showed that depth and year were almost as important as latitude as predictors of parasite distribution. This proves the little value of this guild as indicators of host population structure. Transient parasites could be acceptable to study seasonal migrations of their hosts, but it is recommended to avoid their use as tags for population assessment, either alone or combined with long-lived species. This is especially relevant for elasmobranch hosts, for which the numerical dominance of short-lived species in their parasite assemblages is the rule. Based on these results, and upon a careful selection of suitable species, we recommend using parasites as reliable and robust sources of information that provide significant data for the implementation of management measures that ensure the conservation, recovery and sustainable use of elasmobranchs under exploitation.Fil: Irigoitia, Manuel Marcial. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Incorvaia, Inés Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Timi, Juan Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Parasitic copepods infesting the olfactory sacs of skates from the southwestern Atlantic with the description of a new species of Kroeyerina Wilson, 1932

The olfactory sacs of 488 specimens belonging to 18 species of rajid and arhynchobatid skates from the Argentine Sea were sampled for parasites. No parasitic copepods were found in 11 host species, but siphonostomatoid specimens referable to Kroeyerina Wilson, 1932 (Kroyeriidae) and Brianella corniger Wilson, 1915 (Lernaeopodidae) were found on the spotback skate Atlantoraja castelnaui (Miranda Ribeiro, 1907), the smallnose fanskate Sympterygia bonapartii Müller & Henle, 1841, the bignose fanskate Sympterygia acuta Garman, 1877 and the zipper sand skate Psammobatis extenta (Gar-man, 1913) (Rajiformes: Arhynchobatidae). Additionally, specimens of B. corniger were found in the olfactory sacs of the Rio skate Rioraja agassizii (Müller & Henle, 1841) and attached to the pectoral fins of the Magellan skate Bathyraja magellanica (Philippi, 1902) and the smallthorn sand skate Psammobatis rudis Günther, 1870. A new species, Kroeyerina sudamericana sp. nov., is described and illustrated. The new species most closely resembles Kroeyerina nasuta Wilson, 1932, but can be distinguished from it by the different armature of the antennule, a proportionally shorter genital complex and the chela of the antenna which, when closed, leaves a gap between the corpus and claw, the latter having no spines. The new species represents the first record of Kroeyerina in South American marine waters. The present study also ex-tends the distribution range of B. corniger, previously known only from the Pacific, to include Atlantic waters, and records seven new host species, all of which are members of the Arhynchobatidae.Fil: Irigoitia, Manuel Marcial. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Cantatore, Delfina María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Incorvaia, Inés Silvia. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Timi, Juan Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin