The genus TrifurWilson, 1917 (Siphonostomatoida, Pennellidae) comprises relatively large and conspicuous parasitic copepods infecting the body surface and gills of several marine fishes. Variations in the gross morphology have been used to discriminate between the existing species of Trifur, however all previous descriptions of these species are brief, lacking many important characteristics, especially those of the head and trunk appendages, which usually were lost in the described specimens. In this paper, T. tortuosus is redescribed based on newly collected material from three species of fishes from Argentinean coasts. A detailed description of appendages morphology is given and the validity of T. merluccii Talice, 1936; T. puntaniger Thomé, 1963; T. physiculi Heegaard, 1962 and T. lotellae (Thomson, 1890) is herewith discussed.