LAUSR

During a survey conducted in the Cuiaba and Paraguay Rivers in the Brazilian Pantanal wetland, in the states of Mato Grosso and Mato Grosso do Sul, we found branchiurans associated with Pseudoplatystoma reticulatum , Pseudoplatystoma corruscans, Salminus brasiliensis and Zungaro zungaro. These branchiurans correspond to Argulus chiropteroideus sp. n., Argulus multicolor , Argulus nattereri , Argulus pestifer , Dolops carvalhoi and Dolops longicauda . Besides the description of the new species, in this study we also provide important morphological notes for diagnosis of the other species. Specimens of Argulus chiropteroideus sp. n. were collected from skin of P. reticulatum and P. corruscans. They differ from A. multicolor and Argulus chicomendesi , in the shape of the postantennal spines, which is medially convex and has two lateral and one anterior stout tips in the new species, and for having three claviform, digitate spines on the base of the second maxillae (absent in A. multicolor ; three conical, short spines in A. chicomendesi ). A. chiropteroideus sp. n. do not have an anterior and a posterior spine on first two segments of first antenna, as well as no flagellum on the dorsal surface of the first two pairs of legs, structures present in A. multicolor and A. chicomendesi . The new species also differ from A. multicolor and A. chicomendesi , in the shape and number of sclerites that compound the support rods of the suction cup.