No abstract

The status of the trematode Aponurus laguncula Looss, 1907 in the western Mediterranean is re-assessed by means of a comparative morphological study and rDNA sequences based on newly collected material. A. laguncula (sensu stricto) is redescribed from Trachinus draco L. and a new cryptic species of the 'A. laguncula complex', Aponurus mulli n. sp., is described on the basis of abundant material from Mullus barbatus L. (type-host) and M. surmuletus L. off the Spanish Mediterranean coasts. The new species is differentiated from A. laguncula (sensu stricto) by its: significantly larger, elongate body, with maximum width at the level of the ventral sucker; shorter forebody; distinctly larger sinus-sac, seminal receptacle and seminal vesicle, with the latter also being more elongate; vesicular pars prostatica; more anteriorly located vitellarium, which consists of eight globular follicles; and distinctly smaller eggs, which are also smaller in relation to body size and have both their opercular and anopercular poles rounded. The variability and the allometric growth of the morphological characters in the new species were studied in detail, resulting in additional distinguishing features. Sequences of the large subunit rRNA (28S) gene (domains D1-D3) and ITS2 rRNA gene region for the new species have been submitted to GenBank in order to enhance future studies on species differentiation within the 'A. laguncula complex'.

Two frequently reported but poorly known hemiurid digeneans, Lecithochirium musculus (Looss, 1907) (Lecithochiriinae), from the stomach of Trachinus draco and Citharus linguatula, and Ectenurus lepidus Looss, 1907 (Dinurinae), from the stomach of Spicara maena, are redescribed based on material from off the Barcelona coast of the western Mediterranean. The two species are commented upon, and Lecithochirium israelense Fischthal, 1980 is considered a synonym of L. musculus. Records of the two species in the Mediterranean Basin and North East Atlantic region are summarised.

SUMMARY: The usefulness of fish parasite communities as bioindicators of environmental stress was tested on two benthic fish species, the red mullet (Mullus barbatus) and the spotted flounder (Citharus linguatula), during the spring of 2006 at two sites of the Catalan coast (northwestern Mediterranean): an anthropogenic-impacted area located close to the city of Barcelona, and a less polluted area close to Blanes (Girona). Gonadosomatic and hepatosomatic indices and condition factor were determined for the fishes caught. Prevalence, mean intensity, mean abundance and species richness of the parasites found in the survey were calculated for both species and locations, and the main histological alterations were recorded. Cysts of unknown aetiology and intestinal coccidians were reported only in red mullets from the area close to Barcelona, which were highly parasitized by the digenean Opecoeloides furcatus and the nematode Capillaria sp. However, a higher prevalence of Ichthyophonus sp. was reported in the spotted flounder from Blanes. Cysts of unknown aetiology, some nematodes and Ichthyophonus sp. may be associated with pollution.Keywords: bioindicators, Mediterranean, Mullus barbatus, Citharus linguatula, cysts of unknown etiology (CUEs), Ichthyophonus sp. RESUMEN: Parásitos e histopatología de Mullus barbatus y Citharus linguatula de dos zonas sometidas a diferente grado de contaminación del Mediterráneo noroccidental. -Se ha comparado la utilidad de las comunidades parasíticas de peces como bioindicadores de estrés ambiental en dos especies bentónicas de peces , el salmonete de fango Mullus barbatus y la solleta Citharus linguatula, durante la primavera de 2006 en dos lugares de la costa catalana (Mediterráneo NO): un área fuertemente impactada cerca de la ciudad de Barcelona, y una menos contaminada cerca de Blanes (Girona). Se determinó el índice gonadosomático, el índice hepatosomático y el factor de condición de los peces capturados. Se calculó la prevalencia, intensidad media, abundancia media y riqueza específica de los diferentes parásitos encontrados por especie y localidad, y se analizaron las principales alteraciones histológicas. Se han encontrado quistes de etiología desconocida y coccidios intestinales tan sólo en los ejemplares de M. barbatus de Barcelona, los cuales también estaban altamente parasitados por el digeneo Opecoeloides furcatus y el nematodo Capillaria sp. Se ha detectado Ichthyophonus sp. tan sólo en los ejemplares de C. linguatula, presentando una mayor prevalencia en los ejemplares de Blanes. Los quistes de etiología desconocida, algunos nematodos e Ichthyophonus sp. podrían estar relacionados con la contaminación.