Molecular characterization of larval anisakid nematodes from marine fishes of Madeira by a PCR-based approach, with evidence for a new species

One-hundred and fifteen anisakid larvae from 3 different fish hosts, Aphanopus carbo, Scomber japonicus, and Trachurus picturatus, caught in Madeiran waters, were identified by PCR-RFLP. Three distinct species were identified in A. carbo, namely Anisakis simplex sensu stricto, Anisakis pegreffii, and Anisakis ziphidarum; 5 in S. japonicus, i.e., A. simplex s.s., A. pegreffii, Anisakis physeteris, Anisakis typica, and A. ziphidarum; and 3 in T. picturatus, i.e., A. simplex s.s., A. pegreffii, and A. typica. Anisakis simplex s.s. was the most frequent species in both A. carbo and S. japonicus (54% and 23.5%, respectively). Anisakis pegreffii and A. physeteris occurred with a frequency of 20.6% in S. japonicus, whereas in T. picturatus the most frequent species was A. typica (41.9%), followed by A. simplex s.s. (32.3%). Furthermore, A. carbo and S. japonicus were infected by an apparently undescribed taxon, provisionally named Anisakis sp. A. Based on estimations of the genetic distance, this new taxon seems to be more similar to A. ziphidarum (0.0335) than to other species of the genus.