Abstract
Purpose: To study the monogeneans gill parasites of Heterobranchus bidorsalis (Siluriformes, Clariidae) fish of economic interest in the Bagoue River. Methods: Fifty-five specimens of H. bidorsalis were caught with gillnets in the Bagoué River from August 2018 to January 2019. The monogeneans were individually isolated from the gill and transferred directly onto a slide in a drop of glycerin ammonium picrate mixture (GAP). Results: The new species differ from the previously described Quadriacanthus spp. mainly by the morphology of their sclerotised vagina: Quadriacanthus tanoyaoi sp. nov having a V-shaped, widely open vagina with a central protuberance, and Quadriacanthus bidorsalisi sp. nov having a pear-shaped vagina, composed of a tubular part with a ring near the aperture and a swollen portion. Q. tanoyaoi sp. nov and Q. bidorsalisi sp. nov are different in the shape of the dorsal and ventral anchors (more sturdy for Q. tanoyaoi), of the dorsal and ventral cuneus (triangular vs Y-shaped, respectively), and that of the vagina (V-shaped, widely open with a central protuberance vs pear-shaped, respectively). Conclusion: To date, only Quadriacanthus mandibulatus Francová & Řehulková, 2017 were recognised parasitizing from H. bidorsalis from the Nile River Basin (Sudan) and Lake Turkana (Kenya). The present study with the description of 2 new species expands the number to 3 species of monogeneans for this fish.