Morphological and Molecular Characterization of Hexostoma auxisi Palombi, 1943 (Polyopisthocotylea: Hexostomatidae) from Auxis rochei (Risso, 1810) (Teleostei: Scombridae) off Algerian Waters, Western Mediterranean.

Abstract

INTRODUCTION: Hexostoma auxisi Palombi, 1943 was originally described by Palombi (1943) from Auxis thazard off Italy, Mediterranean Sea. The original description of this species lacks morphological and morpho-metrical data. In addition, no published sequence of this species is available in molecular engines. MATERIALS AND METHODS: Specimens of Hexostoma auxisi were collected from the gills of Auxis rochei (Risso, 1810) off the Algerian coast, Western Mediterranean. Monogenean were stained with acetic carmine, measured and drawn. Furthermore, molecular study was conducted using partial fragment of the mitochondrial cytochrome c oxidase subunit 1 (cox1) of parasites and a tissue sample of the fish's gills on which the monogeneans were found. RESULTS: In this study, we provide morpho-anatomical and morpho-metrical data of Hexostoma auxisi. Our specimens are morphologically close to those described by Palombi (1943) off Italy, Mediterranean Sea. The morphological study was supported by a molecular analysis of cox1 gene that reveals that our sequence of H. auxisi is distinct from its congener H. thynni by 20.51%. CONLUSION: The present study allowed us to confirm the taxonomic status of Hexostoma auxisi which belongs to the genus Hexostoma and the family Hexostomatidae.