First report of Pseudochauhanea mexicana (Mazocraeidea, Chauhaneidae) and Scomberocotyle scomberomori (Mazocraeidea, Thoracocotylidae) in Sphyraena ensis (Perciformes, Sphyraenidae) from the northern Peru

First report of Pseudochauhanea mexicana (Mazocraeidea, Chauhaneidae) and Scombero-cotyle scomberomori (Mazocraeidea, Thoracocotylidae) on the Mexican barracuda Sphyraena ensis (Perciformes, Sphyraenidae) from the northern Peru. Sphyraena ensis is distributed in the Eastern Pacific from Mexico to Chile, including the Galapagos Islands. Despite the wide distribution of this fish, knowledge of the parasitic fauna of S. ensis is restricted to only three monogenean species. The objective of this study was to record and describe two monogenean species of S. ensis in northern Peru. During a parasitological study from May to October 2019, monogeneans were collected from the gills of 138 specimens of S. ensis from Caleta de Zorritos, Contralmirante Villar Province, Tumbes, on the north coast of Peru. Helminths were stained in carmine acetic acid, dehydrated in ethyl alcohol, diaphanized in clove oil and mounted in Canada balsam. To observe the sclerotized structures, several specimens were placed in Hoyer's medium. We identified the following monogeneans not previously reported in Peru: Pseudochauhanea mexicana and Scomberocotyle scomberomori. This is the first report of these two monogeneans in Peru, and the first report of P. mexicana in South America. Furthermore, S. ensis is reported as a new host of S. scomberomori.