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Parasitología latinoamericana

On-line version ISSN 0717-7712

Parasitol. latinoam. vol.58 no.1-2 Santiago Jan. 2003 

Parasitol Latinoam 58: 78 - 79, 2003 FLAP


New host and locality records for Urotocus fusiformis
(Digenea: Leucochloridiidae) in
Pteroptochos tarnii,
a native bird of Patagonia (Argentina)



Urotocus fusiformis is reported parasitizing rectum of Pteroptochos tarnii (Rhinocryptidae) a native bird from Argentinian Patagonian cold temperate forest. Specimens were mounted "in toto" and morphometric data are given. Morphology and dimensions of these specimens conform to the original description. This is the first record for this host and for Argentina.

Key words: Urotocus fusiformis, Digenea, Pteroptochos tarnii, Patagonia, Argentina.


There are no parasitological records for birds inhabiting the Argentinian Patagonian cold temperate forest. The present communication is the first record of Urotocus fusiformis in the native bird, Pteroptochos tarnii (black-throated, huet-huet).

The bird belongs to Rhinocryptidae an endemic family from South America. This species is distributed in the mixed Austrocedrus-Notophagus forest of south Argentina and Chile. This bird has an earthling habitat, digs in the fallen vegetation of the forest, its diet is compound by arthropods and molluscs and nests in caves or in hole trunks1.


Three dead specimens of P. tarnii were found during summer 2002 in the surrounding forest of Gutiérrez (41º10' - 71º 24') and Mascardi (41º17' - 71º 38') lakes, in the National Park of Nahuel Huapí. Only one bird was parisitized with one hundred two specimens. The digeneans were removed from the rectum, transferred to 4% formaline, stained with hydrochloric carmine and mounted in Canada balsam. All measurements are given in micrometers (um) and based on 23 ovigerous specimens and 1 juvenile, mean ± standard deviation and range between brackets. Specimens were deposited in the Colección Nacional de Parasitología (MACN-Pa) Museo Argentino de Ciencias Naturales Bernardino Rivadavia, (Buenos Aires, Argentina) and in the Colección Parasitológica de la Universidad Nacional del Comahue (Bariloche, Argenti-na) No.: 161 (1-24).


Adult: The digenean present a fusiform body and measures 4,083 ± 465.8 (3,209-5,084) long by 709 ± 104.0 (511-852) wide, maximum width at equator. The oral sucker is terminal 60 ± 6.6 (48-72) long by 80 ± 7.0 (65-91) wide. The prepharynx is short 22 ± 5.3 (12-31) long and the pharynx is muscular, 39 ± 3.5 (34-48) long and 67 ± 5.0 (53-74) wide. The oesophagus is shorter than the pre-pharynx and measures 16 ± 4.8 (7-24) long. The caeca contains a dark substance and extends up to 339 ± 42.1 (240-480) from to posterior testis. The ventral sucker was not observed. The gonads are in tandem and located in the last fourth of the body. The testes are slightly oval, the anterior testis is 253 ± 48.1 (192-336) long by 285 ± 49.8 (211-384) wide and the posterior testis is 303 ± 47.3 (211-394) long by 295 ± 42.1 (221-336) wide. The cirrus sac is 107 ± 12.5 (84-139) long by 49 ± 3.1 (41-53) wide. The cirrus was measured everted only in 2 specimens and is 60-65 long. The genital pore is ventral and subterminal. The ovary is situated between testes and is wider than long, 191 ± 19.9 (163-230) long by 229 ± 33.7 (163-269) wide. The Mehlis gland is situated between ovary and posterior testis. The vitellaria is extracaecal and extends from caecal bifurcation up to posterior border of ovary. The metraterm is situated lateral to cirrus sac. The uterus is filled with eggs, and consists of an ascending portion with numerous coils which are greatly distended and occupied the space between caeca. The descending portion, which lays ventral to ascending portion has less extensive coils and is filled with dark brown eggs. The mature eggs are 26 ± 1.3 (24-29) long by 17 ± 1.2 (14-19) wide. The excretory pore is terminal.

Juvenile: The body measures 1,562 long by 142 wide. The diameter of oral sucker is 52.8 and for ventral sucker 55.2. The ventral sucker has a weak development and is situated 528 from the anterior extremity. The pre-pharynx measures 12 long and the pharynx 28.8 long by 43.2 wide.

The definitive host are represented by different birds species2, as Oporornis phi-ladelphia in North America3, and Passer domesticus in South America4.

The life-cycle of the genus includes a pulmonate snail as the only intermediate host. The sporocyst parasitizes the digestive gland, the cercariae does not leave the snail and encyst in situ. Faria Vaz and Ishiata5 cited the pulmonate snail Drymaeus papyraceus (Zonitidae) as intermediate host although they found two ovigerous adults. This record is considered doubtful.

A new monotipical genus Paraurotocus has been created6 but later has been synonimized with Urotocus because there are not real differences between them7. The last author stated that "a lack of ventral sucker in the former is doubtful". We agree with her as we observed the ventral sucker in the juvenile, which is less developed than the oral one. Morphology and dimensions of the Argentinian specimens of U. fusiformis conform to the original description3. This is the first record of U. fusiformis for P. tarnii, and for Argentina.


La presencia de Urotacus fusiformis en el recto de Pterptochos tarnii, un pájaro de la Patagonia Argentina, se describe por primera vez en este huésped y en este país


1.- CANEVARI M, CANEVARI P, CARRIZO G R et al. Nueva guía de aves argentinas, Tomo l. Fundación Acindar, Buenos Aires, 1991, 411 pp.         [ Links ]

2.- TIMON-DAVID J. Recherches experimentales sur le cycle evolutif d´un trematode du genre Urotocus Looss (Digenea, Leucochloridiidae). Ann de Parasitologie 1957; XXXll: 219-42.         [ Links ]

3.- MCINTOSH A. A new species of Trematode, Urotocus fusiformis n. sp., from the mourning warbler. J Parasitol 1935; 21: 55-6.         [ Links ]

4.- TRAVASSOS L, TEIXEIRA DE FREITAS J F, KOHN A. Trematódeos do Brasil. Mem Inst Oswaldo Cruz 1969; 67: 1-886.         [ Links ]

5.- FARIA VAZ J, ISHIATA G. Drymaeus papryraceus (Mawe, 1823) (Pulmonata - Gastropoda - Mollusca) huesped intermediario de Paraurotocus fusiformis (McIntosh, 1935) (Leucochloridiidae - Brachylae-moidea - Digenea - Trematoda). Com Soc Malac Urug 1981; 5: 419-21.         [ Links ]

6.- TRAVASSOS L, KOHN A. Lista dos gêneros incluídos na super-família Brachylaemoidea. Mem Inst Oswaldo Cruz 1966; 64: 11-25.         [ Links ]

7.- POJMANSKA T. Family Leucochloridiidae Poche, 1907. In DI Gibson, A Jones, RA Bray, Keys to the Trematoda, Volume 1, CABI Publishing, Walling-ford, 2002, p 47-51.         [ Links ]

Acknowledgments: To Park Ranger Gerardo Carreras from the Seccional Mascardi, Parque Nacional Nahuel Huapí for collecting the hosts.

* Departamento de Zoología, Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, Avda. Quintral 1250. 8400 Bariloche, Argentina. Fax: +54-2944-422111. E-mail:

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