The presence of the sea leech, Stibarobdella macrothela (Schmarda, 1861) (Hirudinea, Piscicolidae), is marked in the south coast of Brazil, based on the single specimen with 67 mm (CT), collected in the intergill ventral region of a whaler shark, Carcharhinus brachyurus (Günther, 1870) (Chondrichtyes, Carcharhinidae), adult male with about 2 m (CT), being treated of the first registrations of S. macrothela in the Southwest Atlantic and the parasitic association with C. brachyurus.
Stibarobdella macrothela; Carcharhinus brachyurus; Hirudinea; Chondrichthyes; ectoparasitism