RESUMO
This study describes the morphology of Rhabdias elegans Gutierrez, 1945, isolated from the lungs of the toad Rhinella arenarum (Hensel, 1867) from Lomas de Tafi Tucumán, Argentina. This is the first record of R. elegans in R. arenarum from northwestern Argentina as previously described Rhabdias truncata is a species inquirendae. The distribution of R. elegans is extended since it was previously recorded in Buenos Aires, Chaco and Corrientes Provinces, Argentina. Our light microscopical study of morphological details of R. elegans revealed a few previously unreported structures in the apical region including position of the excretory pore and lateral sessile papillae in the tail. In addition, morphometric variability was observed on comparing present specimens and those described in previous studies. Our study made it possible to validate the occurrence of three Rhabdias species occurring in Argentina: R. elegans, R. füelleborni and R. cf. sphaerocephala. The information presented in this study represents an important contribution to the parasitological knowledge of R. arenarum from northwestern Argentina.