First report of Aplectana hylambatis (Nematoda: Cosmocercidae) in amphibians from the San Luis province, Argentina

The studies of helminth parasites in Argentine amphibians have focused on the Dry and Humid Chaco ecoregions; in the Dry Chaco the reports are from the Chaco and Formosa provinces. The aim of this work was to report the first record of Aplectana hylambatis (Baylis, 1927) Travassos, 1931 (Nematoda: Cosmocercidae) from San Luis province and the southernmost record for the Dry Chaco ecoregion. Specimens of Rhinella arenarum (Hensel, 1867) (n = 6), Leptodactylus mystacinus (Burmeister, 1861) (n = 13), and Odontophrynus cf. asper (n = 6) were analyzed. Specimens of A. hylambatis were collected from the large intestine of these hosts and were studied using light and scanning electron microscopy (SEM). In addition, relevant features are described, including the number and arrangement of caudal papillae, and of mamelon-like cuticular protuberances associated to the vulva. The morphological characteristics are compared and discussed in relation to those of specimens collected from other hosts in other localities of the country. The presence of A. hylambatis in localities of the Dry Chaco represents an expansion of the geographic range of this cosmocercid and the first record in L. mystacinus and O. cf. asper from Argentina.