Abstract Rhinella major is one of the component species of the Rhinella granulosa group and is distributed in the neotropical region of the South American continent, being found in anthropized environments. The occurrence of trypanosomes in anurans involves a yet unknown diversity of species and hosts. In the present study, we aimed to describe the first record of Trypanosoma sp. at R. major as a new host. Of the species captured, four were positive for trypomastigote forms of Trypanosoma sp. The morphometry of the trypomastigote forms revealed parasitemia by only one morphotype. There is a need for reports and studies of parasite-host relationships in anurans and a lack of records regarding hemoparasite diversity linked to the Rhinella granulosa group.

Abstract The present study describes Trypanosoma spp. infection and blood parameters in Pterygoplichthys pardalis from the Tapajós River basin in eastern Amazon (Brazil). Of 32 fish examined, 40.6% were infected by Trypanosoma spp., while a total of 112 trypomastigotes were found. Two Trypanosoma morphotypes were characterized and compared with species described in literature infecting other Loricariidae, and a similarity of 94% was found with one species described for another host. The plasma glucose and aspartate aminotransferase levels, hematocrit, number of total erythrocytes, mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC) in the infected and uninfected fish were similar, but hemoglobin was lower in fish infected with Trypanosoma spp. Hemoglobin levels declined with the abundance of the hemoparasites, but the condition factor was similar among fish infected and uninfected by Trypanosoma spp. This is the first study on the hemoparasitism by Trypanosoma spp. and blood parameters in P. pardalis.

Abstract The aim of the present study was to investigate the infracommunities of ectoparasitic crustaceans in Phractocephalus hemioliopterus Bloch and Schneider, 1801, a catfish from the lower Amazon River, in the state of Pará, eastern Amazon region, Brazil. From 12 hosts examined, a total of 45 specimens of crustacean ectoparasites from 5 species were found in the tegument, oral cavity or dorsal fins. The species were: Argulus multicolor, Argulus violaceus, Dolops nana, Dolops discoidalis, and Braga patagonica. Dolops discoidalis was the dominant ectoparasite, while D. nana had the highest mean intensity in the tegument, which was the most infested host site. This is the first record of A. multicolor, A. violaceus, D. nana and B. patagonica parasiting P. hemioliopterus.

Resumen El objetivo del presente estudio fue investigar las infracomunidades de crustáceos ectoparásitos en Phractocephalus hemioliopterus Bloch y Schneider, 1801, un bagre de la parte baja del río Amazonas, en el estado de Pará, en la Amazonía oriental, Brasil. A partir de 12 hospederos examinados, se encontraron un total de 45 ejemplares de crustáceos ectoparásitos de 5 especies en el tegumento, cavidad o aletas dorsales orales. Las especies fueron: Argulus multicolor, Argulus violaceus, Dolops nana, Dolops discoidalis y Braga patagonica. Dolops discoidalis fue el ectoparásito dominante, mientras que D. nana tuvo la intensidad media más alta en el tegumento, que fue el sitio más infestado. Este es el primer registro de A. multicolor, A. violaceus, D. nana y B. patagonica parasitando P. hemioliopterus.