DAO 125:93-100 (2017)  -  DOI: https://doi.org/10.3354/dao03136

Dawestrema cycloancistrium (Monogenea) from the head pores of arapaimas

Cláudia Portes Santos1,*, Maralina Torres da Silva2, František Moravec

1Laboratório de Avaliação e Promoção da Saúde Ambiental, Instituto Oswaldo Cruz - Fiocruz, 21040-360 Rio de Janeiro, RJ, Brazil
2Instituto Federal do Acre, 69911-030 Rio Branco, AC, Brazil
3Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, 370 05 Čské Budějovice, Czech Republic
*Corresponding author:

ABSTRACT: Arapaima gigas is one of the main cultured fish species in South America, and monogenean parasites of this species cause large economic losses to fish farmers. During surveys of the parasites of cultured arapaimas from Mexiana Island in the Amazon River Delta, Rio Branco, in northwestern Brazilian Amazonia, and Yurimaguas, Peru, the monogenean Dawestrema cycloancistrium was found in the gills of A. gigas as well as in previously unreported sites, i.e. the head pores and chambers. The aim of this study was to investigate the transmission route of this parasite and its geographical distribution as well as to describe its morphology as observed by light and confocal imaging. Phalloidin labeling confirmed the presence of 2 prostatic reservoirs and showed muscular branches of fibers supporting haptoral sclerites. In arapaimas, the head connects to the gill chambers via 2 perforated scales located at the dorsolateral sides of the distal part of the head. The scales connect to thin channels and chambers situated in the proximal part of the head. These chambers are filled with cephalic mucus, which flows out to the environment through terminal pores. Adults and egg masses of monogeneans were found on the gills and inside the head pores and cavities of fish along with cephalic mucus. This indicates a specialized method of parasite transmission from adult fish to fingerlings during parental care (holding offspring in the mouth) or via head secretions, providing evidence of a new adapted mechanism of dispersion.


KEY WORDS: Arapaima gigas · Pirarucu · Parasite · Freshwater fish · Monogenea · Amazonia · Brazil · Peru


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Cite this article as: Portes Santos C, da Silva MT, Moravec F (2017) Dawestrema cycloancistrium (Monogenea) from the head pores of arapaimas. Dis Aquat Org 125:93-100. https://doi.org/10.3354/dao03136

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