Trichodina heterodentaía (Ciliophora: Trichodinidae): a new parasite for Piar actus mesopotamicus (Pisces: Characidae)

摘要

Trichodinids are mobile peritrichous ciliated protozoa, and widely known as ectocommensals and/or parasites offish and other aquatic organisms. Little is known about the trichodinid fauna in Brazilian fish. This study reports Trichodina het-erodentataDuncan, 1977 as a new parasite for freshwater fish Piaractus mesopotamicus Holmberg, 1887. This is the first record of this trichodinid in southeastern Brazil. Fifty specimens impregnated with 2% silver nitrate and another fifty stained with Giemsa wereused for morphometry on the taxonomic characteristics. T. heterodentata in this study is medium size, with a disc-shaped body measuring 49.0 to 61.0 um, parasitizing the skin, fins and gills of pacu. Measurement comparisons between the present materialand other records from different countries are presented.