New Records of Digenea (Platyhelminthes) in Labrid Fishes from the Algerian Coast

A study was conducted to investigate the biodiversity of Digenea (Metazoa, Platyhelminthes), intestinal mesoparasites infecting two teleost fish species of the family Labridae: Symphodus tinca (Linnaeus, 1758) and Xyrichtys novacula (Linnaeus, 1758). Between 2019 and 2022, the intestines of 243 Labridae specimens, belonging to these two species, were examined for the presence of Digenean parasites. Fish were collected from several localities along the Algiers coast, located in the southwestern Mediterranean Sea.

A detailed taxonomic and morpho-anatomical analysis of the recovered parasites led to the identification of four Digenean species: Proctoeces maculatus Looss, 1901; Gaevskajatrema perezi Mathias, 1926; Helicometra fasciata Rudolphi, 1819; and one unidentified species of the genus Helicometra (Helicometra sp.). These parasites were assigned to two families: Opecoelidae Ozaki, 1925 and Fellodistomidae Nicoll, 1909. Although previously recorded in other parts of the Mediterranean Sea, these species are reported here for the first time in teleost hosts from Algerian coastal waters.

These new records broaden our current understanding of the geographic distribution, host range, and biodiversity of Digenean parasites in North African marine ecosystems.

Our project, based at the Biodiversity and Environment: Interactions–Genomes (LBEIG), aims to significantly increase the number of Digeneans known from Algeria through an intensive survey of teleost fishes.