A new species of Ameloblastella Kritsky, Mendoza-Franco & Scholz, 2000 (Monogenoidea: Dactylogyridae) from South American freshwater catfishes (Siluriformes: Pimelodidae).

Ameloblastella martinae n. sp. is described from the gills of the pimelodid catfishes (Siluriformes: Pimelodidae) Sorubim lima (Bloch & Schneider) (type-host) and Hemisorubim platyrhynchos (Valenciennes) in the Peruvian Amazonia, and on Pseudoplatystoma corruscans (Spix & Agassiz) and P.

The description of two new species of Chloromyxum from skates in the Argentine Sea reveals that a limited geographic host distribution causes phylogenetic lineage separation of myxozoans in Chondrichthyes.

During a survey on the myxosporean fauna of Rajiformes from the Atlantic coast of Argentina, in waters off Buenos Aires Province (34°-42°S; 53°-62°W), the gall bladders of 217 specimens belonging to seven species of skates, representatives of two families, were examined. As a result, three species of Chloromyxum Mingazzini, 1890, namely C. atlantoraji n.

Distribution of anisakid nematodes parasitizing rajiform skates under commercial exploitation in the Southwestern Atlantic.

In order to evaluate the infestation by anisakids present in elasmobranchs and their distribution in the Argentine Sea, this study was carried at a regional scale with the following aims: 1) to identify those anisakid species present in skates under exploitation; 2) to characterize quantitatively these infestations and 3) to determine those factors driving the variability in parasite burdens across skate species. A total of 351 skates, belonging to 3 species (218 Sympterygia bonapartii, 86 Zearaja chilensis and 47 Atlantoraja castelnaui) and from different localities of the Argentine Sea were examined for anisakids. Parasites were found in the stomach wall at high prevalence in some samples.