Tylodelphys brevis Drago & Lunaschi, 2008

Drago, Fabiana B., Lunaschi, Lía I. & Draghi, Regina, 2014, Digenean fauna in raptors from northeastern Argentina, with the description of a new species of Strigea (Digenea: Strigeidae), Zootaxa 3785 (2), pp. 258-270 : 266

Tylodelphys brevis Drago & Lunaschi, 2008

( Fig. 7 )

Host: Busarellus nigricollis (Latham) , black–collared hawk ( Accipitridae ).

Site of infection: intestine.

Voucher specimens: MLP 6715.

Distribution and hosts: Tylodelphys brevis was described by Drago & Lunaschi (2008) parasitizing Mycteria americana L. ( Ciconiidae ) from Argentina.

Measurements: Based on 3 specimens. Body indistinctly bipartite, 386–440 (409) long. Forebody 238–280 (260) long by 233–270 (258) wide. Hindbody 143–160 (149) long by 193–224 (210) wide. Ratio of forebody length to hindbody length 1:0.56–0.6 (0.58). Oral sucker round, subterminal, 55–58 (57) long by 57–60 (58) wide. Ventral sucker transversely elongate, pre-equatorial, 40–49 (44) long by 67–78 (73) wide. Suckers width ratio 1:0.9. Pharynx longitudinally elongate, immediately posterior to oral sucker, 52–55 (54) long by 25–26 (26) wide. Ratio of oral sucker width to pharynx width 1:0.4–0.5 (0.4). Pseudosuckers well developed, 63–71 (69) long by 48–67 (56) wide. Ratio of pseudosuckers length to body length 1:5.4–6.4 (6). Ratio of oral sucker length to pseudosuckers length 1:1.1–1.3 (1.2). Holdfast organ round to elliptical, immediately posterior to ventral sucker, 60–83 (71) long by 74–95 (85) wide. Ratio of holdfast organ length to body length 1:4.7–7.4 (6). Testes tandem, extended transversally occupying whole width of hindbody; anterior testis 19–23 (21) long by 65–68 (67) wide; posterior testis 41–49 (45) long by 193–198 (195) wide. Ovary ovoid, pretesticular, 36 long by 100 wide. Vitellarium in fore– and hindbody; in forebody extend from nearly midway between intestinal bifurcation and ventral sucker, in hindbody extending to posterior end. Uterus without eggs or with 1 large egg, 74 long by 60 wide. Ratio of egg length to body length 1:5.2.

Remarks: The specimens obtained from B. nigricollis agree well morphologically with those described from M. americana , but differ by being smaller (386–440 vs. 570–851), by having larger ventral sucker (40–49 x 67 –78 vs. 24– 36 x 27–54), and smaller eggs (74 x 60 vs. 83–102 × 45–64). This could be related to the degree of development, because only one specimen was gravid. Dubois (1978) described specimens of Tylodelphys sp. in B. nigricollis from Colombia, that differ from specimens here studied in size (760–900 vs. 386–440) and arrangement of vitelline follicles, which extend from the level of the intestinal bifurcation. The life cycles of Tylodelphys species include fishes and amphibians as second intermediate hosts. In Argentina, no full life cycle has been studied, nevertheless Szidat (1969) described four metacercariae of this genus parasitizing freshwater fishes from northeastern Argentina: Tylodelphylus jenynsiae Szidat, 1969 in the pericardial cavity from Jenynsia lineata (Jenyns) , Tylodelphylus sp. 1 in brain from Hoplias malabaricus (Bloch) , Tylodelphylus sp. 2 in the pericardial cavity from Gymnotus carapo L. and Tylodelphylus sp. 3 in the visceral cavity from Neofundulus paraguayensis (Eigenmann & Kennedy) . Unfortunately, it is not possible to compare them with our specimens because their descriptions are brief and their adults unknown.

According to Di Giacomo (2005), B. nigricollis from Formosa Province, mainly feeds on aquatic snails ( Pomacea sp.) and fishes ( Hoplias cf. malabaricus , Synbranchus marmoratus Bloch , Hoplosternum cf. littorale and Hoplerythrinus unitaeniatus (Spix & Agassiz) . Therefore, the presence of T. brevis in this raptor is associated with its fish–eating habits.

The finding of this diplostomid in B. nigricollis represents a new host record.

Figures

FIGURES 4 – 11. Digeneans from raptors. 4. Strigea proteolytica n. sp. from Buteogallus urubitinga, scale bar = 250 µm. 5. Strigea falconis brasiliana Szidat, 1929 from Caracara plancus, scale bar = 250 µm. 6. Neodiplostomum travassosi Dubois, 1937 from Buteogallus meridionalis, scale bar = 200 µm. 7. Tylodelphys brevis Drago & Lunaschi, 2008 from Busarellus nigricollis, scale bar = 100 µm. 8. Posthodiplostomum macrocotyle Dubois, 1937 from B. nigricollis, scale bar 200 µm. 9. Enlarged view of copulatory bursa of P. macrocotyle, scale bar 50 µm. 10. Spaniometra variolaris (Fuhrmann, 1904) from R. sociabilis, scale bar 500 µm. 11. Megalophallus deblocki Kostadinova, Vaucher & Gibson, 2006 from R. sociabilis, scale bar 100 µm. Abbreviations: B, body wall; Gc, genital cone; P, prepuce.