Digenea ) in Taraba major ( Vieillot ) ( Aves : Thamnophilidae ) from Argentina

Pojmanskia riosae (Digenea: Leucochloridiidae) and Lubens lubens (Digenea: Dicrocoeliidae) are described from the intestine and cloaca of the Chororo or Great Antshrike, Taraba major (Passeriformes: Thamnophilidae) from Formosa Province, Argentina. The finding of P. riosae constitutes the first record of the genus for South American birds and the first record in thamnophilid birds. The discovery of L. lubens in T. major represents a new host record and the first report of this species in Argentina. Moreover, Lubens phelpsi is synonymized with L. lubens .

On the other hand, the specimens here described have some resemblance to those of Leucochloridium parcum Travassos, 1922described by Travassos (1922, 1928) from Brazil, reported parasitizing passeriform birds, Psarocolius decumanus (Pallas) (as Ostinops d.) (Icteridae) and Tachyphonus cristatus brunneus (Spix) (Thraupidae).Leucochloridium parcum was transferred by Kagan (1952) to genus Urogonimus Monticelli, 1888 [as U. parcus (Travassos, 1922)], and by Pojmańska (1973) to genus Michajlovia Pojmańska, 1973[as M. parcum (Travassos, 1922)] when considering the genital pore in ventral position.Finally, Brasil et al. (1991) analyzed the type material and specimens found in Passer domesticus (L.) (Passeridae) from Brazil, and established the dorsal position of the genital pore, therefore retained this species in the genus Leucochloridium Carus, 1835.This species is similar to P. riosae by possessing the gonads arranged in triangle, vitelline follicles extending between the pharynx and the posterior testis, and the uterus with extracaecal loops in forebody.Nevertheless, differs by having a dorsal genital pore, a Laurer's canal opening in the excretory vesicle without forming a seminal receptacle, a cirrus sac spherical, and by lacking an external seminal vesicle.The absence of these characters allow us to conclude that the specimens found parasitizing T. major belong to P. riosae.
Pojmanskia riosae is a generalist parasite reported in a wide range of birds belonging to Cardinalidae, Cuculidae, Dendrocolaptidae, Polioptilidae, Sylviidae, Troglodytidae, Trogonidae and Tyrannidae.This finding allows us to increase the list of definitive host of this digenean, adding the family Thamnophilidae, and to enlarge the geographical distribution of genus Pojmanskia to Argentina.Gorgoderoidea Looss, 1899 Dicrocoeliidae Looss, 1899 Leipertrematinae Yamaguti, 1958Lubens Travassos, 1919 Lubens lubens (Braun, 1901) Shtrom, 1940 (Figure 5; Tables 1 and 2) Description: (based on 2 specimens) Body oval to elongate oval; tegument with small papillae.Oral sucker subterminal, rounded.Ventral sucker well developed, slightly larger than the oral sucker, situated in anterior third of the body.Pharynx, globular.Oesophagus short.Caeca long and wide, reaching posterior end of body.Genital pore median, at level of posterior border of pharynx.Cirrus sac small.Testes intercaecal, rounded, approximately equal in size, symmetrical.Ovary dextral, rounded, located behind testes and separated from them by loops of uterus.Seminal receptacle and Laurer's canal present.Mehlis' gland diffuse.Vitelline bands composed of numerous follicles occupying caecal and extracaecal regions from posterior border of ventral sucker or anterior margin of testes.Uterus occupying all available space of hindbody; eggs operculated.Excretory vesicle not seen.Excretory pore terminal.Considering the key provided by Pojmańska (2008), the specimens collected from the Great Antshrike are members of the genus Lubens by possessing a well developed ventral sucker, long caeca, testes located posterolateral to ventral sucker, ovary posterior to testes, vitellarium forming narrow bands, which usually begin at level of ventral sucker.The genus Lubens was considered as a subgenus of Eurytrema Looss, 1907 by Travassos (1919Travassos ( , 1944Travassos ( , 1945) ) and Bhalerao (1936).Shtrom (1940) raised it to full generic status, and afterwards was treated in this way by Denton and Byrd (1951), Skrjabin and Evranova (1952), Heyneman et al. (1960), Travassos et al. (1969), Yamaguti (1971) and Pojmańska (2008).
The specimens found parasitizing T. major are morphometrically similar to those described by Travassos (1944) for passeriform and gruiform birds, but are smaller than those reported in Harpagus diodon (Temm) (Falconiformes), and the specimens studied in Mexico by Lamothe-Argumedo (1979) from Ortalis poliocephala (Wagler) (as O. vetula p.) (Table 1).Heyneman et al. (1960) described a new species, Lubens phelpsi Heyneman, Brenes & Díaz Ungría, 1960, based on one specimen found parasitizing the Amazonian Umbrellabird, Cephalopterus ornatus Geof.(Cotingidae) from Venezuela.These authors considered valid all species synonymized with L. lubens by Travassos (1944), and characterized L. phelpsi by having the oral sucker slightly larger than the ventral sucker, a larger body, by parasitize other host species, and by possessing a different geographical distribution.However, the ventral sucker larger than the oral sucker also occurs in the type specimen of L. lubens from R. rupicola described by Braun (1901),

Table 1 .
Comparative morphometric data for Lubens lubens from Neotropical birds.Range of measurements obtained from itemized morphometric data for Laterallus melanophaius (Vieillot) in the table provided on page 75.yCalculated from original descriptions and in the specimens from Progne chalybea (Gmelin), H. diodon and Myiozetetes similis (Spix).The morphometric differences could be given by effect of the compression during fixation.This analysis allows us to conclude that L. phelpsi should be consider as a synonymous of L. lubens, because the morphometric characters proposed by the authors for its creation, are not sufficient to distinguish significantly both species.Moreover, L. lubens is a generalist parasite with a wide geographical distribution (see Table2).The finding of L. lubens in T. major increases the list of definitive host of this digenean and enlarges the geographical distribution of genus Lubens to Argentina.
* Range of measurements obtained from itemized morphometric data for each host species in the tables provided on pages 74-77.** Originally described as Lubens phelpsi Heyneman, Brenes & Díaz Ungría, 1960 j Measurements provided in the specific diagnosis, correspond to specimens from H. diodon.d

Table 2 .
List of definitive host species and countries of Lubens lubens in the American continent.