Molecular identification of Pseudoterranova cattani and P. decipiens E (Nematoda: Anisakidae) from fishes of the Austral region: morphological and ecological characterization

TIMI, J.T.; MATTIUCCI, S.; PAOLETTI, M.; LANFRANCHI, A.L.; ALARCOS, A.J.; GARBIN, L.; GEORGE-NASCIMENTO, M.; NASCETTI, G.

Viña del Mar

Simposio; VIII International Symposium of Fish Parasites (ISFV); 2011

Universidad de Antofagasta, Universidad Católica de la Ssma., Universidade Federal Rural Rio de Janeiro, Instituto Oswaldo Cruz, Universidad Nacional de Mar del Plata, etc.

Larvae of the genus Pseudoterranova constitute a risk for human health due the severe pathology they can cause when are consumed with raw or undercooked fish. Adults of the P. decipiens species complex are world-wide distributed parasites of otariids and phocids and comprise six sibling species morphologically very similar, especially at larval stage. Third-stage larvae of P. decipiens have been reported in several fish species in Argentina; however, there are still no studies dealing with their specific identification in this region. Here, we performed the first genetic and morphological characterization of larval Pseudoterranova from fish species caught off Argentine coasts (Acanthistius patachonicus, Paralichthys patagonicus and Pseudopercis semifasciata). Morphology of larvae was also compared with that of larvae obtained from Notothenia coriiceps from Antarctic waters. Genetic/molecular identification of larvae was performed by sequence analysis of the mtDNA cox-2 gene, in comparison with all species of the P. decipiens complex, including adult forms of P. cattani collected from Otaria flavescens from Argentina and Chile and P. decipiens E from Leptonychotes weddelli. Larvae from Argentine waters were identified as belonging to the species P. cattani, while those from N. coriiceps to the sibling P. decipiens E. Multivariate comparisons showed that larval morphometry was similar between specimens of P. cattani from Argentina, but significantly different from those of P. decipiens E, indicating therefore that larval forms are morphologically distinguishable across species. It is also confirmed that the life-cycle of the sibling species of P. decipiens complex involve mainly demersal and benthic organisms, but with a marked preference by large-bodied benthophagous fish.