Redescription of Haliotrematoides mediohamides (Monogenea: Dactylogyridae), a gill parasite of the Pacific porgy Calamus brachysomus (Perciformes: Sparidae) from the Eastern Pacific Ocean

Abstract The monogenean Haliotrematoides mediohamides Kritsky & Mendoza-Franco, 2009 (Monogenea: Dactylogyridae) is redescribed based on examination of the type specimen (paratypes) and newly collected specimens parasitizing the gills of the Pacific porgy, Calamus brachysomus (Lockington, 1880) (Perciformes: Sparidae) (type host), a neritic fish captured off the coastal zone of Puerto Pizarro, Tumbes, Peru. Even though this monogenean was described 12 years ago, that description did not report some of the unique morphological features of H. mediohamides and neither did it offer a whole-mount drawing of this species. The most important characteristics of H. mediohamides are: 1) a male copulatory organ with hook-shaped distal end, 2) a non-coiled vaginal duct, 3) numerous secretory gland-cells associated with the peduncle, 4) a chandelier-shaped extrinsic adductor muscles articulated with superficial roots of the anchors, 5) a single tadpole-shaped prostatic reservoir, and 6) a vas deferens anteriorly convoluted. In addition, the first whole-mount drawing of H. mediohamides, as well as morphometric data are provided. Haliotrematoides mediohamides represents the first record of Haliotrematoides in South America. Haliotrematoides mediohamides is the third dactylogyrid species recorded to infect C. brachysomus in Peru.