Ichthyofilaria argentinensis Incorvaia, 1999 (Nematoda: Philometridae) is redescribed from type specimens and from parasites collected from the swim bladder of Argentine hakes Merluccius hubbsi Marini, 1933 caught at the Gulf of San Jorge (46°30'S, 66°30'W), Argentine Sea, in July, 1998. Sixteen out of 80 hakes (20%) were found to be parasitised by gravid females of this philometrid. After revision of both these nematodes and type material, the following differences from the original description of the species were observed: (a) cuticle with fine transverse striations, instead of smooth cuticle; (b) presence of cephalic papillae and a pair of amphids; (c) absence of swellings in the oesophagus; (d) oesophageal gland appendix very large and lobulate rather than small and vermiform, and (d) presence of vulva and vagina. The morphological features given in the redescription allow the confirmation of the identity of I. argentinensis as a valid species and to distinguish it from other members of the genus.
A new strigeid digenean, Strigea meridionalis sp. n., is described from the small intestine of the savanna hawk, Buteogallus meridionalis (Latham) (Aves: Accipitridae), from Formosa Province, Argentina. This species is characterised by the absence of a neck region in the hindbody, the presence of entire testes, a copulatory bursa with a membranous fold originated from the muscular ring (Ringnapf) and by the arrangement of vitelline follicles in the forebody. Other two strigeid species collected from the savanna hawk, Strigea elliptica (Brandes, 1888) and Strigea microbursa Pearson et Dubois, 1985, are described and illustrated. Strigea microbursa is reported for the first time from the Neotropical Region and B. meridionalis represents a new host record for S. elliptica. These findings allow us to increase the knowledge of these species, adding new metric and morphological data. A key to the species of the Neotropical Strigea Abildgaard, 1790 is presented including data on their geographical distribution.
Two new species of bothriocephalidean cestodes, Clestobothrium splendidum sp. n. from Merluccius australis (Hutton) and Clestobothrium cristinae sp. n. from Merluccius hubbsi Marini from the Patagonian shelf of Argentina, are described. Clestobothrium splendidum can be typified by the following characteristics: a medium-sized strobila composed of 410-528 proglottides that are much wider than long; 49-90 testes per mature proglottis, partially surrounding the ovary posteriorly; a transversely elongated genital pore situated anterior to spurious articulations; presence of a genital atrium; a globular cirrus-sac occupying 4-6% of mature proglottis width; a vagina with sphincter and three pairs of osmoregulatory canals on each side of the proglottis. Clestobothrium cristinae is characterised by its small size; 71-219 proglottides; 39-64 testes per mature proglottis, usually surrounding completely the ovary posteriorly; a rounded genital pore situated at the same level of spurious articulations; an oval cirrus-sac occupying 8-16% of mature proglottis width; and three pairs of osmoregulatory canals on each side of the proglottis. Clestobothrium cristinae shares with C. splendidum the type and distribution of microtriches, except for the central surface delimited by two lips. Additionally, type and voucher materials of Clestobothrium crassiceps (Rudolphi, 1819) from Merluccius merluccius were studied. A key to species is provided.
A new species Wardium paucispinosum (Eucestoda: Hymenolepididae) parasite from the intestine of Larus maculipennis (Lichtenstein) from Mar del Plata, Argentina is described. The distinctive features of the new species are: strobilar length 52.8 mm; 10 aploparaksoid rostellar hooks, 14 (12-17) pm long; ratio between cirrus pouch length and mature proglottid width (CPL/MPW) 0.38 (0.27-0.50); regular cylindrical evaginated cirrus, 90 x 10 pm, with distal end without spines and proximal and medium thirds covered with spines 7 pm long; simple tubular membranous vagina, 110 x 10 pm, without sclcrotised portions and sphincters; eggs fusiform, 77 x 44 pm. Besides, llymenolepis semiductilis Szidat, 1964, from the intestine of Larus dominicanus and L. maculipennis from Santa Fé, Argentina is transferred to the genus Wardium Mayhew, 1925, based on the presence and shape of the rostellar hooks.