New species of Guidus Ivanov, 2006 (Cestoda: Phyllobothriidea) from Bathyraja magellanica (Philippi) from the Patagonian Continental Shelf of Argentina

Specimens representing two new species of Guidus Ivanov, 2006 were collected from the Magellan skate (Bathyraja magellanica [Philippi]) in Patagonian Continental Shelf Argentina, Southwestern Atlantic Ocean. francoi sp. n. and magellanicus differ their congeners by a particular combination features, including type bothridia, worm length, number testes, distribution vitelline follicles. is distinguished G. having fewer proglottids, testes higher ratio between cirrus sac length proglottid width. The microthrix pattern described, based on specimens n., newly argentinense 2006. These three share presence wide aristate gladiate spinitriches proximal bothridial surface, narrow rim, filitriches distal surface. diagnosis revised to include several features exhibited (i.e., indentations stalks, follicles, eggs grouped cocoons). discovery B. increases batoids one three. specificity herein described reinforces tight association rays genera Bathyraja.