New species of Raphidascaris (Sprentascaris) (Nematoda: Anisakidae) in Rineloricaria steinbachi (Actinopterygii: Loricariidae) from Northwest Argentina Author Ailán-Choke, Lorena Gisela Author Ramallo, Geraldine Author Davies, Dora text Zootaxa 2017 4231 1 129 136 journal article 37068 10.11646/zootaxa.4231.1.10 b9f12d8b-b4f5-47e6-9134-b24e93ea6d94 1175-5326 293599 8D663345-A7C6-4249-86E2-C79FE6D985C6 Key to species of the subgenus Sprentascaris parasitic in Neotropical freshwater fishes 1 Males with caudal alae and six pairs of postanal papillae.......................................................2 - Males without caudal alae and less than six pairs of postanal papillae.............................................3 2 Ventricular appendix/oesophageal length ratio in males and females is 1:0.16. Caudal alae well-developed. Vulva situated at 1.82–3.94 mm from anterior extremity, approximately at 1/3 of body length........................... R. ( S. ) mahnerti - Ventricular appendix/oesophageal length ratio in males is 1:0.34 and in females 1:0.36. Caudal alae rudimentary. Vulva at short distance below oesophagus, at 0.40–1.06 mm from anterior extremity............................... R. ( S. ) lanfrediae 3 Lateral alae well developed (broad). In males, three pairs of postanal papillae......................................4 - Lateral alae absent or rudimentary. In males, five pairs of postanal papillae........................................5 4 Symmetrical and equal lips. In males, 22 pairs of preanal papillae. In females, mature eggs embryonated, thin-shelled................................................................................................ R. ( S. ) marano - Dorsal lips smaller than ventrolateral ones. In males, 16 pairs of preanal papillae. In females, mature eggs embryonated with rough shell and membranous striations................................................. R. ( S. ) saltaensis sp. nov. 5 Narrow oesophagus. Rounded tail in both sexes. Posterior end of males with ventral cuticular ornamentation. Length of spic- ules 0.14 mm . Parasites of Pimelodidae fishes................................................... R. ( S. ) pimelodi - Oesophagus markedly broad. Pointed tail tip in both sexes. Males with smooth posterior ventral surface. Length of spicules between 0.15–0.25 mm .................................................................... R. ( S. ) hypostomi