Ecological Data of Travassosnema travassosi travassosi (Dracunculoidea: Guyanemidae) from the Humour of the Eyes of Acestrorhynchus lacustris from Tibagi River, Paraná, Brazil

Vol. 97(1): 51-52, January 2002

Ângela Teresa Silva-Souza/⁺, Aurélia Saraiva*

Departamento de Biologia Animal e Vegetal, CCB, Universidade Estadual de Londrina, Caixa Postal 6001, 86051-990 Londrina, PR, Brasil *Departamento de Zoologia e Antropologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal

Data obtained between 1990 and 1995 provide, for the first time, ecological information of the parasitic nematode Travassosnema travassosi travassosi Costa, Moreira & Oliveira, 1991 from Acestrorhynchus lacustris (Characiformes: Acestrorhynchidae) collected in the Tibagi River, Sertanópolis, Paraná, Brazil. These nematode occurred with low prevalences (7.7% to 28.6%) and intensities (1 to 3) during almost the whole year. The observation of mature females throughout the year indicate that liberation of larvae can occur during all the year around. This is the first report on the occurrence of T. travassosi travassosi inside the eyes. These nematodes were mostly located in humour of the eyes (87% of cases), being less frequently detected in tissues behind the eyes (13% of cases).

Key words: Travassosnema travassosi travassosi - Nematoda - parasites - Acestrorhynchus lacustris - Tibagi River - Paraná - Brazil

The genus Travassosnema Costa Moreira & Oliveira 1991 (Dracunculoidea: Guyanemidae) is represented by medium sized nematodes with a rounded cephalic end, without a buccal capsule and with the oesophagus divided into an anterior muscular and a posterior glandular portions. The posterior glandular portion of oesophagus is provided with a long dorsal appendix extending posteriorly, a feature that makes this genus easily distinguishable from the genus Guyanema Petter, 1974 (Costa et al. 1991, Moravec 1998).

Two subspecies of the only species T. travassosi Costa Moreira & Oliveira, 1991 are known to occur in South American freshwater fishes, Acestrorhynchus lacustris Reinhardt, 1874 (Characiformes: Acestrorhynchidae) being the only known host of these parasites (Moravec 1998, Vicente & Pinto 1999). T. travassosi travassosi Costa Moreira & Oliveira, 1991 was detected in the tissues behind the eyes (orbits) from fishes from the Três Marias Reservoir on the São Francisco River, State of Minas Gerais, Brazil (Costa et al. 1991), while T. travassosi paranaensis Moravec Kohn & Fernandes, 1993 was detected in the abdominal cavity from fishes of the Paraná River near Guaíra, Brazil (Moravec et al. 1993). No data have been published on the prevalence and the intensity of infection of these nematodes.

During a study of helminth parasites of the eyes of A. lacustris conducted between 1990 and 1995 in the Tibagi River, Paraná, Brazil, the dracunculoid nematode T. travassosi travassosi was observed. Data related to ecological indexes of prevalence and intensity of infection of these parasites are evaluated in this paper.

MATERIALS AND METHODS

RESULTS

DISCUSSION

REFERENCES

Fig. 1 | Fig. 2 | Table

⁺Corresponding author. Fax: +55-43-371.4207. E-mail: ateresa@uel.br

Received 28 March 2001

Accepted 13 September 2001